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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid .
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is the name of the first molecule 2-hydroxyl-2,3-dimethyl pentanol ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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how can we determine if a reaction is fast or slow to happen ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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when you start the last reaction mechanism , i know it is e1 elimination , but the first two were dehydration of alcohol , is there a specific name for this third reaction ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide .
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- the delta represents heat ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters .
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what 's the rate-determining step in the first example ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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why koh acts as base as well as nucleophile ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here .
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why does the alcohol group act like a base , when oxygen does not like to be positively charged ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction .
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why do you need to heat up the acids ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism .
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how is the 1 carbon a carbocation once the hydrogen is taken off ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values .
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what is the phosphoric acid used for if the reaction used sulfuric acid ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values .
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would the first 2 examples be e2 because the oxygen is accepting the proton from the sulfuric acid ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism .
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how the electrons are gon na make a double bond ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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where did the h+ come from ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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i have 2 questions : ) 1- do we need energy or anything to make the br take the electrons at e1 reaction or does it happen on it on ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism .
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2- after the methanol ( oxygen ) forms a bond with h from the beta carbon now it will have a positive charge , so then what would happen and now what is it called with the extra h ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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what is the difference between this e1 reaction and an e1 reaction that creates an alkene with a strong base ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion .
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will there be 2 products if there are 2 beta hydrogen ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values .
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in the reference to jay talking about the dehydration of the cyclohexanol , ( starting around 0 ) are all dehydration reactions e1 reactions when a strong acid is present ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene .
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the ethanol is removing the hydrogen because its a nucleopphile , why didnt it just go and attach to the positively charged carbon ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid .
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so are the first 2 examples dehydrations rxns and the last one is dehydrohalogenation ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion .
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how do we recognize alpha and beta groups ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values .
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when you said bronsted lowry acid ( which i do n't recall hear of from my teachers ) is that an electrophile ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond .
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in acidic conditions , like in the cyclohexane example , are you supposed to deprotonate before or after the elimination has occurred ?
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let 's look at the mechanism for an e1 elimination reaction , and we 'll start with our substrate , so on the left . let 's say we 're dealing with alkyl halide . so the carbon that 's bonded to our halogen would be the alpha carbon , and the carbon next to that carbon would be the beta carbon , so we need a beta hydrogen for this reaction . the first step of an e1 elimination mechanism is loss of our leaving group , so loss of leaving group , let me just write that in here really quickly , and in this case , the electrons would come off onto our leaving group in the first step of the mechanism . so we 're taking a bond away from this carbon , the one that i 've circled in red here , so that carbon is going from being sp3 hybridized to being sp2 hybridized . so now we have a carbocation , and we know that carbocations , sp2 hybridized carbons have planar geometry around them , so i 've attempted to show the planar geometry around this carbocation . so that 's the first step , loss of the leaving group to form a carbocation . in the second step , our base comes along and takes this proton , which leaves these electrons behind , and those electrons move in to form our alkene , so this is the second step of the mechanism , which is the base takes , or abstracts , a proton , so base takes a proton to form our alkene . and let me go ahead and highlight those electrons , so these electrons here in magenta moved in to form our double bond , and we form our product , we form our alkene . so the first step of the mechanism , the loss of the leaving group , this turns out to be the rate determining step , so this is the slowest step of the mechanism . so if you 're writing a rate law , the rate of this reaction would be equal to the rate constant k times the concentration of your substrate , so that 's what studies have shown , that these mechanisms depend on the concentration of only your substrate , this over here on the left , so it 's first order with respect to the substrate . and that 's because of this rate determining step . the loss of the leaving group is the rate determining step , and so the concentration of your substrate , your starting material , that 's what matters . your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction . so let 's talk about one more point here in the mechanism , and that is the formation of this carbocation . since we have a carbocation in this mechanism , we need to think about the possibility of rearrangements in the mechanism , and you need to think what would form , what substrate would form a stable carbocation , so something like a tertiary substrate forming a tertiary carbocation would be favorable for an e1 mechanism . here we have a tertiary alkyl halides , and let 's say this tertiary alkyl halide undergoes an e1 elimination reaction . so the carbon that 's bonded to the iodine must be our alpha carbon , and then we would have three beta carbons , so that 's a beta carbon , that 's a beta carbon , and that 's a beta carbon . so the first step in an e1 mechanism is loss of our leaving group , so if i draw the lone pairs of electrons in here on iodine , i know that these electrons in this bond would come off onto iodine to form the iodide anion , so let me draw that in here , so we would make the iodide anion , and let me highlight our electron , so the electrons in this bond come off onto the iodine to form the iodide anion . and this is an excellent leaving group . iodide is an excellent leaving group , and you know that by looking at pka values . the iodide anion is the conjugate base of a very strong acid , hi , with a approximate pka value of negative 11 , so hi is very good at donating a proton , which must mean that the conjugate base is very stable , so the iodide anion is an excellent leaving group . so if we lose the iodide anion , that means we 're gon na have a carbocation , so we lost a bond to this carbon in red , so we 're gon na form a carbocation , let me go ahead and draw that in , so this is a planar carbocation , and so the carbon , let me go ahead and highlight it here , the carbon in red has a plus one formal charge , it lost a bond . so that 's the first step of an e1 elimination mechanism . the second step of an e1 elimination mechanism is the base comes along , and it takes a proton from a beta carbon , so our base in this case would be ethanol , so let me go ahead and draw in lone pairs of electrons on the oxygen , so notice we 're also heating this reaction , so the ethanol is gon na function as a base , so ethanol 's not a strong base , but it can take a proton , so let me go ahead and draw in a proton right here , and a lone pair of electrons on the oxygen is going to take this proton , and the electrons would move into here to form our alkene , so let me go ahead and draw our product , let me put that in here , and let me highlight some electrons , so the electrons in blue moved in here to form our double bond . so a couple of points about this reaction , one point is , when you 're looking at sn1 mechanisms , the first step is loss of a leaving group to form your carbocation , so when you get to this carbocation , you might think , well , why is ethanol acting as a base here ? why could n't it act as a nucleophile ? and the answer is , the ethanol certainly can act as a nucleophile , and it would attack the positively-charged carbon , and you would definitely get a substitution product for this reaction as well , so if ethanol acts as a nucleophile , you 're gon na get a substitution reaction , an sn1 mechanism . if the ethanol acts as a base , you 're gon na get an e1 elimination mechanism , so here , we 're just gon na focus on the elimination product , and we wo n't worry about the substitution product , but we will talk about this stuff in a later video , 'cause that would definitely happen . alright , something else i wan na talk about is we had three beta carbons over here , and if i look at these three beta carbons , and i just picked one of them , i just said that this carbon right here , let me highlight it , i just took a proton from this carbon , but it does n't matter which of those carbons that we take a proton off because of symmetry , let me go ahead and draw this in over here , so this is my carbocation , let 's say , and let 's say we took a proton from this carbon , so our weak base comes along , and takes a proton from here , and these electrons have moved into here , that would give us the same product , right ? so this would be , let me go and highlight those electrons , so these electrons in dark blue would move in to form our double bond , but this is the same as that product . alcohols can also react via an e1 mechanism . the carbon that 's bonded to the oh would be the alpha carbon , and the carbon next to that would be the beta carbon , so reacting an alcohol with sulfuric acid and heating up your reaction mixture will give you an alkene , and sometimes , phosphoric acid is used instead of sulfuric acid . so we saw the first step of an e1 mechanism was loss of a leaving group , but if that happens here , if these electrons come off onto the oxygen , that would form hydroxide as your leaving group , and the hydroxide anion is a poor leaving group , and we know that by looking at pka values . down here is the hydroxide anion , it is the conjugate base to water , but water is not a great asset , and we know that from the pka value here , so water is not great at donating a proton , which means that the hydroxide anion is not that stable , and since the hydroxide anion is not that stable , it 's not a great leaving group . so let 's go ahead and take off this arrow here , because the first step is not loss of a leaving group , the first step is a proton transfer . we have a strong acid here , sulfuric acid , and the alcohol will act as a base and take a proton from sulfuric acid . and that would form water as your leaving group , and water is a much better leaving group than the hydroxide anion , and again , we know that by pka values . water is the conjugate base to the hydronium ion , h3o+ , which is much better at donating a proton , the pka value is much , much lower . and that means that water is stable , so the first step , the first step when you are doing an e1 mechanism with an alcohol is to protonate the oh group . so here 's our alcohol , and the carbon bonded to the oh is our alpha carbon , and then these carbons next to the alpha carbon would all be beta carbons . we just saw the first step is a proton transfer , a lone pair of electrons on the oxygen take a proton from sulfuric acid , so we transfer a proton , and let 's go ahead and draw in what we would have now , so there 'd be a plus-one formal charge on the oxygen , so let 's highlight our electrons in magenta , these electrons took this proton to form this bond , and now we have water as a leaving group , let me just fix this hydrogen here really fast , and these electrons can come off onto our oxygen , so that gives us water as our leaving group , and let me go ahead and draw in the water molecule here , and let me highlight electrons , the electrons in light blue , in this bond , came off onto the oxygen , which forms water , and we know water is a good leaving group . we took a bond away from this carbon in red , so that carbon would now be a carbocation , so let me draw in our carbocation here , so the carbon in red is now positively charged , so let me draw in a plus-one formal charge on that carbon , the next step of our mechanism , we know a weak base comes along and takes a proton , one of the protons on one of the beta carbons over here , so let 's just say it 's this one , and i 'm just gon na draw in a generic base , so a generic base right here , which is gon na take this proton , and then these electrons are gon na move in to form our product , so let me draw our product in here , and let me highlight those electrons . so the electrons in , let 's use green this time , the electrons in green moved in here to form our double bond , to form our alkene . so i just put a generic base , let me go ahead and talk about the base for a second here . i just put in a generic base , sometimes you might see water acting as a base , sometimes you might see hso4- , right , the conjugate base to sulfuric acid acting as the base , different textbooks give you different things , i do n't think it really matters , but one of those acting as a weak base , it 's probably water , takes this proton to form your alkene . sometimes this reaction is called a dehydration reaction since we lost water in the process .
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your base ca n't do anything until you lose your leaving group . and so , since the base does not participate in the rate determining step , it participates in the second step , the concentration of the base has no effect on the rate of the reaction , so it 's the concentration of the substrate only , and since it 's only dependent on the concentration of the substrate , that 's where the one comes from in e1 , so i 'm gon na go ahead and write this out here , so in e1 mechanism , the one comes from the fact this is a unimolecular , a unimolecular rate law here , and the e comes from the fact that this is an elimination reaction , so when you see e1 , that 's what you 're thinking about , it 's an elimination reaction , and it 's unimolecular , the overall rate of the reaction only depends on the concentration of your substrate , so if you increase , let 's say you have , let 's say this was your substrate right here , and you increase the concentration of your substrate , let me just write this down , so if you increase the concentration of your substrate by a factor of two , you would also increase the rate of reaction by a factor of two , so it 's first order with respect to the substrate , so this is some general chemistry here . if you increase the concentration of your base by a factor of two , you would have no effect on the overall rate of the reaction .
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is there a general rule that tells when to deprotonate in acidic/basic conditions ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass .
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does the pond freeze first because the pond has more surface area in relation to its volume ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water .
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is the reason for the ocean freezing not as fast as the pond ( because the ocean has salt in it ) , the the same reason why people put salt on the road to melt the snow ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world .
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how do you use the scientific method ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world .
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or rather , is the scientific method the only valid way to explain things ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment .
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wait , since salt water has a lower freezing point , is that why people pour salt on snowy/icy road ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water .
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why does salt lower the freezing point ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water .
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would another reason for freezing be the relative size of the pond and the ocean ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , the next part that i will do is the experiment . experiment . and there you go .
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is it better to use the scientific method to conduct an experiment than conducting an experiment without the scientific method ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't .
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would n't the ocean be affected by the iceberg near the water ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice .
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would the motion of the waves make it harder to freeze because essentially freezing is making the molecules slow down , but while the waves move , it would be harder to do so ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster .
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because the ocean has such powerful currents propelling it , would n't they crack the ice or something ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't .
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but salt and water mix if the water is to be evaporated the salt will be left behind so how come when the water freezes the salt is still there why ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world .
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or rather , is the scientific method the only valid way to explain things ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , the next part that i will do is the experiment . experiment . and there you go .
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would n't it have been better to take water from the regions that sal was testing ( the lake and the ocean ) and then conduct the experiment ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world .
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who created the scientific method ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice .
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could the ocean being bigger than the pond another reason ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point .
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what is the difference between a theory and a hypothesis ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world .
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is a mathematical formula necessary in the scientific method ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , the next part that i will do is the experiment . experiment . and there you go .
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can you be scientific without a mathematical expression of your experiment ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis .
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why does the fresh water freeze faster than the salt water ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else .
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would that work or it does definitely does have to be a different temperature for the same effect ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ?
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where can you naturally find freshwater ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis .
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why does fresh water freeze faster then salt water does ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world .
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does `` scientific method '' mean the steps of doing something but it is more scientific and the results are more exact ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world .
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do you always have to do experiments by using the scientific method ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't .
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how would you get the salt out of the oceanic water ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't .
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can i say that the pond froze faster because it does n't have a large amount of water unlike the ocean ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does .
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can you explain how to use a compound microscope ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment .
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what is the freezing point of salt water ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again .
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why do ponds freeze faster than swamps ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment .
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does the ocean conveyor belt affect the temperature of the salt water that then has an impact on freezing the water to make ice ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice .
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the ocean has a high concentration of salt right ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment .
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does salt water freeze at a lower freezing point because salt is a mineral and mineral water is hard to freeze ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point .
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should n't the hypothesis be in an if , then statement ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again .
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do oceans not freeze over fast because of the salt ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world .
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why we use scientific method ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation .
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does the pond freeze because the ocean is warmer than the pond ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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you control for the material of the glass . you control for how much water there is . but , then you test it .
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does how much water have anything to do with why the freshwater pond froze first ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world .
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would the scientific method be able to prove that the scientific method works ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world .
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is the function of lipids closer to carbohydrates or protein ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point .
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does anyone know if this hypothesis is actually correct ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , the next part that i will do is the experiment . experiment . and there you go .
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what are variables in an experiment ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water .
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besides the salt does the move meant of the sea change the freezing rate ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis .
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is it also because the water from the ocean is moving , while the water in the pond is still ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water .
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does n't the freezing of pond depends on the area ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't .
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does the ocean freeze slower because it 's moving water ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water .
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why does saltwater has a lower freezing point than freshwater ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world .
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would it be helpful to memorize all the steps of the scientific method ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water .
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why is saltwater has lower freezing point than freshwater ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again .
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why saltwater freeze longer than freshwater ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point .
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is n't the hypothesis the same as a prediction ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . ''
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how did hassan ibn al - haytham ( alhazen ) make that quote ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment .
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so salt water has a lower freezing point ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out .
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does n't a lot of science attempt to detect phenomenon that ca n't be observed directly ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass .
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does the volume change how its affected by the surface area ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point .
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should n't there be a step before you make your hypothesis of research ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world .
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how is the scientific method used in everyday life ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again .
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does the pond freeze first because of its volume ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method .
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as shown in the picture , why does the pond freezes from the sides and not from the center ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy .
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if the fairy does n't fit the scientific method , how can we prove the fairy theory is true or not ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world .
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do i have to refer to steps of the scientific method each time i come up with a hypothesis ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment .
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why does salt water have lower freezing point than freshwater ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment .
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does salt water help to freeze the water ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world .
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can you use the scientific method for everything ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment .
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was the celsius measurement of temperature built around the freezing/boiling point of water ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water .
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so , if the salt in ocean lowers the freezing point , where does ice land come from ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't .
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why does hot water freeze quicker ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't .
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so , if the pond/distilled water does n't freeze at 0 celsius , that does n't mean your testable explanation is wrong , right ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't .
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because it could freeze at a higher temperature than salt water , but does n't freeze at 0 celsius ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't .
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i know , that pond water may freeze at 0 celsius , depending where you are , but what if ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment .
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1 why does salt water has a lower freezing point than fresh water ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice .
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does the currents in the ocean have an effect on how long it takes for the ocean to freeze ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't .
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no i thought it was the current in the water that keeps the molecules moving and therefore that makes it harder to freeze ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't .
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what does the salt actually do at molecular level ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water .
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does saltwater actually freeze at a lower point than freshwater ?
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let 's explore the scientific method . which at first might seem a bit intimidating , but when we walk through it , you 'll see that it 's actually almost a common-sense way of looking at the world and making progress in our understanding of the world and feeling good about that progress of our understanding of the world . so , let 's just use a tangible example here , and we 'll walk through what we could consider the steps of the scientific method , and you 'll see different steps articulated in different ways , but they all boil down to the same thing . you observe something about reality , and you say , well , let me try to come up with a reason for why that observation happens , and then you try to test that explanation . it 's very important that you come up with explanations that you can test , and then you can see if they 're true , and then based on whether they 're true , you keep iterating . if it 's not true , you come up with another explanation . if it is true , but it does n't explain everything , well once again , you try to explain more of it . so , as a tangible example , let 's say that you live in , in i do n't know , northern canada or something , and let 's say that you live near the beach , but there 's also a pond near your house , and you notice that the pond , it tends to freeze over sooner in the winter than the ocean does . it does that faster and even does it at higher temperatures than when the ocean seems to freeze over . so , you could view that as your observation . so , the first step is you 're making an observation . observation . in our particular case is that the pond freezes over at higher temperatures than the ocean does , and it freezes over sooner in the winter . well , the next question that you might wan na , or the next step you could view as a scientific method . it does n't have to be this regimented , but this is a structured way of thinking about it . well , ask yourself a question . ask a question . why does , so in this particular question , or in this particular scenario , why does the pond tend to freeze over faster and at higher temperatures than the ocean does ? well , you then try to answer that question , and this is a key part of the scientific method , is what you do in this third step , is that you try to create an explanation , but what 's key is that it is a testable explanation . so , you try to create a testable explanation . testable explanation , and this is kind of the core , one of the core pillars of the scientific method , and this testable explanation is called your hypotypothesis . your hypothesis . and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water . than fresh water . so , this , right over here , this would be a good hypothesis . it does n't matter whether the hypothesis is actually true or not . we have n't actually run the experiment , but it 's a good one , because we can construct an experiment that tests this very well . now , what would be an example of a bad hypothesis or of something that you could n't even necessarily consider as part of the scientific method ? well , you could say that there is a fairy that blesses that blesses , let 's say that performs magic , performs magic on the pond to freeze it faster . freeze it faster . and , the reason why this is n't so good is that this is not so testable , because it 's depending on this fairy , and you do n't know how to convince the fairy to try to do it again . you have n't seen the fairy . you have n't observed the fairy . it 's not based on any observation , and so this one right over here , this would not be a good hypothesis for the scientific method , so we would wan na rule that one out . so , let 's go back to our testable explanation , our hypothesis . salt water has a lower freezing point than fresh water . well , the next step would be to make a prediction based on that , and this is the part where we 're really designing an experiment . so , you could just view all of this as designing . let me do this in a different color . where we wan na design an experiment . design an experiment . and in that experiments lets say , and let 's see , the next two steps i will put as part of this experimental . whoops . i messed up . let me , i did my undo step . so , the next part that i will do is the experiment . experiment . and there you go . so , the first thing is , we 'll say i take , you know , there 's all sorts of things that are going on outside . the ocean has waves . you know , maybe there are boats going by that might potentially break up the ice . so , i just wan na isolate that one variable that i care about , whether something is salt water or not , and i want a control for everything else . so , i want a control for whether there 's waves or not or whether there 's wind or any other possible explanation for why the pond freezes over faster . so , what i do , in a very controlled environment i take two cups . i take two cups . that 's one cup and two cups , and i put water in those cups . i put water in those cups . now , let 's say i start with distilled water , but then this one stays , the first one right over here stays distilled , and distilled means that through evaporation i 've taken out all of the impurities of that water , and in the second one i take that distilled water , and i throw a bunch of salt in it . so , this one is fresh , very fresh , and in fact , far fresher than you would find in a pond . it 's distilled water . and then this is over here , this is salt water . so , you would n't see the salt , but just for our visuals , you depict it . then we would make a prediction , and we could even view this as step 4 , our prediction . we predict that the fresh water will freeze at a higher temperature than the salt water . so , our prediction , let 's say the fresh freezes at zero degrees celsius , but salt does n't . salt water does n't . salt water does n't . so , what you then do is that you test your prediction . so , then you test it . and how would you test it ? well , you could have a very accurate freezer that is exactly at zero degrees celsius , and you put both of these cups into it , and you wan na make sure that they 're identical and everything where you control for everything else . you control for the surface area . you control for the material of the glass . you control for how much water there is . but , then you test it . then you see what happened from your test . leave it in overnight , and if you see that the fresh water has frozen over , so it 's frozen over , but the salt water has n't , well then that seems to validate your testable explanation . that salt water has a lower freezing point than fresh water , and if it did n't freeze , well it 's like , okay , well maybe that , or if there is n't a difference , maybe either both of them did n't freeze or both of them did freeze , then you might say , well , okay , that was n't a good explanation . i have to find another explanation for why the ocean seems to freeze at a lower temperature . or , you might say , well that 's part of the explanation , but that by itself does n't explain it , or you might now wan na ask even further questions about , well , when does salt water freeze , and what else is it dependent on ? do the waves have an impact ? does the wind have an impact ? so , then you can go into the process of iterating and refining . so , you then refine , refine , refine and iterate on the process . when i 'm talking about iterate , you 're doing it over again , but then , based on the things that you 've learned . so , you might come up with a more refined testable explanation , or you might come up with more experiments that could get you a better understanding of the difference between fresh and salt water , or you might try to come up with experiments for why exactly , what is it about the salt that makes this water harder to freeze ? so , that 's essentially the essence of the scientific method , and i wan na emphasize this is n't some , you know , bizarre thing . this is logical reasoning . make a testable explanation for something that you 're observing in the world , and then you test it , and you see if your explanation seems to hold up based on the data from your test . and then whether or not it holds up , you then keep going , and you keep refining . and you keep learning more about the world , and the reason why this is better than just saying , oh well , look , okay , i see the pond has frozen over and the ocean has n't , it must be the salt water , and you know , i just feel good about that , is that you ca n't feel good about that . there 's a million different reasons , and you should n't just go on your gut , 'cause at some point , your gut might be right 90 % of the time , but that 10 % that it 's wrong , you 're going to be passing on knowledge or assumptions about the world that are n't true , and then other people are going to build on that , and then all of our knowledge is going to be built on kind of a shaky foundation , and so the scientific method ensures that our foundation is strong . and i 'll leave you with the gentleman who 's often considered to be the father , or one of the fathers of the scientific method . he lived in cairo , and in what is now egypt , nearly 1,000 or roughly 1,000 years ago . and he was a famous astronomer and phycisist and mathematician . and his quote is a pretty powerful one , 'cause i think it even stands today : `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , ... '' let me start over , just so i can get the dramatic effect right . `` the duty of the man who investigates the writings of scientists , if learning the truth is his goal , is to make himself an enemy of all that he reads , and ... attack it from every side . he should also suspect himself as he performs his critical examination of it , so that he may avoid falling into either prejudice or leniency . '' hasan ibn al-haytham , and his latinized name is alhazen . so , he 's saying be skeptical , and not just skeptical of what other people write and read , but even of yourself . and another aspect of the scientific method which is super important is , if someone says they made a hypothesis and they tested and they got a result , in order for that to be a good test and in order for that to be a good hypothesis , that experiment has to be reproducible . someone ca n't say , oh it 's only , you know , a certain time that only happens once every 100 years and not , that that 's why it happened that day . it has to be reproducible , and reproducible is key , because then another skeptical scientist like yourself can say , let me see if i can reproduce it . let me not just believe it , because that person looks like they 're smart , and they said that it is true .
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and so , in this particular case , a testable explanation could be that , well the ocean is made up of salt water , and this pond is fresh water , so your testable explanation could be salt water , salt water has lower freezing point . has lower freezing , freezing point . lower freezing point , so it takes colder temperatures to freeze it than fresh water .
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can surface area has a relation to freezing point ?
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