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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 know who else helped create the scientific method as well ?
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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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in the video about the testable hypothesis what is the freezing water 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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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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but why does salt water have 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 , 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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does the salt water freeze slower because of increased movement of water in the ocean or is it because the salt melts the 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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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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how dose the salt in the ocean 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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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 prediction and 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 , 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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is the reason also that the ocean is moving ?
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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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but why does the 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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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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is it because it would melt the ice until a certain 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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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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can you say the pond freezes faster because its smaller than 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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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 a hypothesis be 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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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 .
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could it also have something to do with the ocean has continual flow of water and a pond does n't ?
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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 , 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 .
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what is the difference between a prediction and an inference ?
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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 is a controlled 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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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 a hypothesis have to be 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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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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what is the history 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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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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should we today not discuss how life came to be from various perspectives to encourage the use 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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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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can the fresh water freeze faster because it is not moving ?
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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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and does the ocean not make any heat from eaves moving keeping it warm as if you are cold you move and you get warm , would that be why ocean water doesn not freeze as fast as a pond will as it 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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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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which freezes faster a lake or a sea ?
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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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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 .
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does n't the pond freeze over first because its not in constant motion ?
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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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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 .
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why is freud 's psychoanalysis considered unscientific ?
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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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please correct me if i 'm wrong ... what exactly is the difference between the hypothesis and the 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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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 pond freezes faster than the sea 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 , 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 .
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distilled water is basically pure water , 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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does the salt water freeze slower because of the density ?
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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 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 .
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what does sal means by a testable explanation ?
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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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i 'm not sure , but is n't it true that 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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does the scientific method include reproducible ?
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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 , 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 .
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also , what does sal mean by reproducible ?
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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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how long does it take for the whole pond to freeze and for how long will it stay frozen ?
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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 solution , such as a sugar solution , also have a lower freezing point than the distilled 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 , 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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the narrator says : `` the fresh water freezes at higher temperature than the salt water '' and i get confused , because is n't actually a lower temperature 0 degrees ?
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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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lol xd sal : now , what would be an example of a bad hypothesis or something that you could n't even necessarily consider as part 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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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 n't the salt water have a higher freezing point than the 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 prediction practically the same thing as the 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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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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will the pond freeze if theres very little 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 , 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 the salt keep the water from freezing ?
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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 does the salt water do to water to give it a separate 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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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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how could a little pond freeze over quicker than the ocean ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse .
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who comes up with ideas of options and who makes the final decision ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work .
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when is the frame considered to have artistic or historic value ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work .
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why is the frame so important ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work .
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how does the frame push and pull ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look .
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when was the first time artist started framing their art work ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that .
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the framer said that wyeth liked to pick a frame that matched a color in the painting , but a framer should not do that ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here .
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is that the real painting of andrew wyeth 's christina 's world ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here .
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how to decide if we should put glass on painting or not ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work .
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why not follow the traditions of the time period or the artist in choosing a frame ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues .
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if you were to put a horribly made , bland , wood frame on an absolutely dazzling masterpiece , would it make it as horrible-looking as the frame ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure .
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would the frames matter to the appearance of the paintings ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work .
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so the frame is also important ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that .
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does the color of the frame effect the painting ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back .
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do museums often choose to re-frame the works they receive ?
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( modern music ) - [ peter ] the frame shop here at the museum of modern art is actually unique . we do most of the framing for the collection , for exhibitions and traveling exhibitions . anything that is wood is made inside . we have a small woodworking shop . we have seven people working at the department but we produce a tremendous amount of work . in the case of cristina 's world , it ca n't be too modern . it has to fit with a certain context . ultimately the best frame is the one that does n't call attention to itself . the frame has a way of pushing and pulling . normally if you had a landscape , it would be what is called a cove , a frame that comes out and creates a window into the work . this works in reverse . this one the painting come forward and the frame goes back . the first thing i wanted to do was to understand why the frame was not working . what is it about the frame that could be improved upon ? it was not original to the work . framers talk about frames in terms of weight , not necessarily in terms of look . the frame could be too light , it could be too heavy . the frame that it had was a little bit light . a little ( mumbles ) even though it had a gold band on the inside . the gilded liner of the frame was actually touching the chimneys of the house . wyeth spent a great deal of time and effort coming all the way too the edge . so what 's important that we see the entire panel . this painting actually is floating . there are two frames in one here . it 's not damaging or causing any pressure . many of the frames that wyeth selected for his work were painted and he always wanted to pick a color from the painting and use that color in the frame . if the artist does it it 's one thing , but a framer should not be doing that . i picked what i thought would be a very natural wood and basically set the painting within the frame as a beautiful little jewel . the whole frames is made from one single piece of wood so that the grain just continues . we knew from the beginning that we were going to have a gold band . i decided to put a cove on the inside to separate the gilding . the next step is to design the panel . one element that would justify angling the panel to the outside is the roof of the house . then you have to decide how that panel is going to end . this is an abrupt stop . it has another angle to the back . the frame will appear almost floating on the wall because when you light it it 's going to cast a shadow behind it . after you make the frame then you start thinking about the different stains . once you put a stain on the panel you ca n't take it off and that 's where you come in . we 're making as many samples as possible using the exact same piece of wood . you can see the difference if you put them next to it . these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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these are very very minor variations that ultimately you do n't pay attention to , but in terms of the framing it 's rather important and it has a way of affecting how we see a painting . ( modern music )
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in the case of modern art , how much input would the artist typically have in the framing process ?
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what i have here are three numbers plotted on the number line . we have the number a , the number c , the number b . and then we have three -- ( laughs ) we have four inequalities , actually . four inequalities that involve absolute value . and what i want to do is figure out which is these inequalities are true , given where a , c and b are on the number line . and i encourage you to pause the video and try to think through it on your own . all right , let 's look at this first one . it says that , `` a is less than b . '' so if we look at a and we look at b , a is clearly to the left of b on the number line . so we know that this is true . even more we know that a is negative , it 's to the left of zero , while b is positive . which is , if one thing is negative and the other thing is positive , the negative thing is definitely going to be less than the positive thing . but even easier than that , a is to the left of b on the number line . if you 're to the left of something else on the number line you 're less than that other thing . because the number line , at least the way we 've constructed it , it increases from left to right . all right , the next statement , `` the absolute value of a is greater than the absolute value of b . '' well , let 's just think about where these are on the number line . so we 've already said a is three hash marks to the left of zero . that is a . so what is going to be the absolute value of a ? well , the absolute value of a is the distance that a is from zero . so the distance that a is from zero is one , two , three hash marks . so the absolute value of a is just going to be that same distance on the positive side . so the point that we marked as c is also the absolute value of a . so that is also the absolute value of a . the absolute value of a -- sorry , a is three to the left of zero . absolute value of a is going to be three to the right . it 's just a measure of , how many hash marks is it from zero ? well , it 's three hash marks from zero so we put it right over here . so is the absolute value of a greater than the absolute value of b ? or what 's the absolute value of b ? well , b is one , two , three , four , five , six , seven , eight hash marks to the right of zero . and so the absolute value of b is going to be on the eighth hash mark . because it 's eight hash marks to the right . so this is also the absolute value of b . and this is consistent with what we 've learned about absolute value . absolute value of a positive number is just going to be that number again . absolute value of a negative number is going to be the opposite of that number . and absolute value of zero is just going to be zero . so is the absolute value of a greater than the absolute value of b ? well , no . absolute value of a is to the left of the absolute value of b on our number line . it is less than the absolute value of b . so this is not true . all right , next statement . `` absolute value of a is less than the absolute value of c. '' well , we already know that the absolute value of a is the same value as c. so what 's the absolute value of c ? well , the absolute value of a positive number is just going to be that number . so this point right over here is also the absolute value of c. so we see that the absolute value of a is equal to the absolute value of c. it 's not less than . so we are going to mark that off . we could have written , `` absolute value of a is equal to absolute value of c. '' that would have been true . all right , last one . a is less than c. well , once again a is to the left of c on the number line . so that is true , because our number line is increasing as we go from left to right . if one number is to the left of another number , it is less than the other number . so a is indeed less than c. and we are done .
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all right , next statement . `` absolute value of a is less than the absolute value of c. '' well , we already know that the absolute value of a is the same value as c. so what 's the absolute value of c ? well , the absolute value of a positive number is just going to be that number .
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do we really have to represent the absolute value with the two lines ?
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what i have here are three numbers plotted on the number line . we have the number a , the number c , the number b . and then we have three -- ( laughs ) we have four inequalities , actually . four inequalities that involve absolute value . and what i want to do is figure out which is these inequalities are true , given where a , c and b are on the number line . and i encourage you to pause the video and try to think through it on your own . all right , let 's look at this first one . it says that , `` a is less than b . '' so if we look at a and we look at b , a is clearly to the left of b on the number line . so we know that this is true . even more we know that a is negative , it 's to the left of zero , while b is positive . which is , if one thing is negative and the other thing is positive , the negative thing is definitely going to be less than the positive thing . but even easier than that , a is to the left of b on the number line . if you 're to the left of something else on the number line you 're less than that other thing . because the number line , at least the way we 've constructed it , it increases from left to right . all right , the next statement , `` the absolute value of a is greater than the absolute value of b . '' well , let 's just think about where these are on the number line . so we 've already said a is three hash marks to the left of zero . that is a . so what is going to be the absolute value of a ? well , the absolute value of a is the distance that a is from zero . so the distance that a is from zero is one , two , three hash marks . so the absolute value of a is just going to be that same distance on the positive side . so the point that we marked as c is also the absolute value of a . so that is also the absolute value of a . the absolute value of a -- sorry , a is three to the left of zero . absolute value of a is going to be three to the right . it 's just a measure of , how many hash marks is it from zero ? well , it 's three hash marks from zero so we put it right over here . so is the absolute value of a greater than the absolute value of b ? or what 's the absolute value of b ? well , b is one , two , three , four , five , six , seven , eight hash marks to the right of zero . and so the absolute value of b is going to be on the eighth hash mark . because it 's eight hash marks to the right . so this is also the absolute value of b . and this is consistent with what we 've learned about absolute value . absolute value of a positive number is just going to be that number again . absolute value of a negative number is going to be the opposite of that number . and absolute value of zero is just going to be zero . so is the absolute value of a greater than the absolute value of b ? well , no . absolute value of a is to the left of the absolute value of b on our number line . it is less than the absolute value of b . so this is not true . all right , next statement . `` absolute value of a is less than the absolute value of c. '' well , we already know that the absolute value of a is the same value as c. so what 's the absolute value of c ? well , the absolute value of a positive number is just going to be that number . so this point right over here is also the absolute value of c. so we see that the absolute value of a is equal to the absolute value of c. it 's not less than . so we are going to mark that off . we could have written , `` absolute value of a is equal to absolute value of c. '' that would have been true . all right , last one . a is less than c. well , once again a is to the left of c on the number line . so that is true , because our number line is increasing as we go from left to right . if one number is to the left of another number , it is less than the other number . so a is indeed less than c. and we are done .
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what i have here are three numbers plotted on the number line . we have the number a , the number c , the number b . and then we have three -- ( laughs ) we have four inequalities , actually .
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did sal actually say `` the number `` b '' ?
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what i have here are three numbers plotted on the number line . we have the number a , the number c , the number b . and then we have three -- ( laughs ) we have four inequalities , actually . four inequalities that involve absolute value . and what i want to do is figure out which is these inequalities are true , given where a , c and b are on the number line . and i encourage you to pause the video and try to think through it on your own . all right , let 's look at this first one . it says that , `` a is less than b . '' so if we look at a and we look at b , a is clearly to the left of b on the number line . so we know that this is true . even more we know that a is negative , it 's to the left of zero , while b is positive . which is , if one thing is negative and the other thing is positive , the negative thing is definitely going to be less than the positive thing . but even easier than that , a is to the left of b on the number line . if you 're to the left of something else on the number line you 're less than that other thing . because the number line , at least the way we 've constructed it , it increases from left to right . all right , the next statement , `` the absolute value of a is greater than the absolute value of b . '' well , let 's just think about where these are on the number line . so we 've already said a is three hash marks to the left of zero . that is a . so what is going to be the absolute value of a ? well , the absolute value of a is the distance that a is from zero . so the distance that a is from zero is one , two , three hash marks . so the absolute value of a is just going to be that same distance on the positive side . so the point that we marked as c is also the absolute value of a . so that is also the absolute value of a . the absolute value of a -- sorry , a is three to the left of zero . absolute value of a is going to be three to the right . it 's just a measure of , how many hash marks is it from zero ? well , it 's three hash marks from zero so we put it right over here . so is the absolute value of a greater than the absolute value of b ? or what 's the absolute value of b ? well , b is one , two , three , four , five , six , seven , eight hash marks to the right of zero . and so the absolute value of b is going to be on the eighth hash mark . because it 's eight hash marks to the right . so this is also the absolute value of b . and this is consistent with what we 've learned about absolute value . absolute value of a positive number is just going to be that number again . absolute value of a negative number is going to be the opposite of that number . and absolute value of zero is just going to be zero . so is the absolute value of a greater than the absolute value of b ? well , no . absolute value of a is to the left of the absolute value of b on our number line . it is less than the absolute value of b . so this is not true . all right , next statement . `` absolute value of a is less than the absolute value of c. '' well , we already know that the absolute value of a is the same value as c. so what 's the absolute value of c ? well , the absolute value of a positive number is just going to be that number . so this point right over here is also the absolute value of c. so we see that the absolute value of a is equal to the absolute value of c. it 's not less than . so we are going to mark that off . we could have written , `` absolute value of a is equal to absolute value of c. '' that would have been true . all right , last one . a is less than c. well , once again a is to the left of c on the number line . so that is true , because our number line is increasing as we go from left to right . if one number is to the left of another number , it is less than the other number . so a is indeed less than c. and we are done .
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if you 're to the left of something else on the number line you 're less than that other thing . because the number line , at least the way we 've constructed it , it increases from left to right . all right , the next statement , `` the absolute value of a is greater than the absolute value of b . ''
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what does `` increases from left to right '' ?
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what i have here are three numbers plotted on the number line . we have the number a , the number c , the number b . and then we have three -- ( laughs ) we have four inequalities , actually . four inequalities that involve absolute value . and what i want to do is figure out which is these inequalities are true , given where a , c and b are on the number line . and i encourage you to pause the video and try to think through it on your own . all right , let 's look at this first one . it says that , `` a is less than b . '' so if we look at a and we look at b , a is clearly to the left of b on the number line . so we know that this is true . even more we know that a is negative , it 's to the left of zero , while b is positive . which is , if one thing is negative and the other thing is positive , the negative thing is definitely going to be less than the positive thing . but even easier than that , a is to the left of b on the number line . if you 're to the left of something else on the number line you 're less than that other thing . because the number line , at least the way we 've constructed it , it increases from left to right . all right , the next statement , `` the absolute value of a is greater than the absolute value of b . '' well , let 's just think about where these are on the number line . so we 've already said a is three hash marks to the left of zero . that is a . so what is going to be the absolute value of a ? well , the absolute value of a is the distance that a is from zero . so the distance that a is from zero is one , two , three hash marks . so the absolute value of a is just going to be that same distance on the positive side . so the point that we marked as c is also the absolute value of a . so that is also the absolute value of a . the absolute value of a -- sorry , a is three to the left of zero . absolute value of a is going to be three to the right . it 's just a measure of , how many hash marks is it from zero ? well , it 's three hash marks from zero so we put it right over here . so is the absolute value of a greater than the absolute value of b ? or what 's the absolute value of b ? well , b is one , two , three , four , five , six , seven , eight hash marks to the right of zero . and so the absolute value of b is going to be on the eighth hash mark . because it 's eight hash marks to the right . so this is also the absolute value of b . and this is consistent with what we 've learned about absolute value . absolute value of a positive number is just going to be that number again . absolute value of a negative number is going to be the opposite of that number . and absolute value of zero is just going to be zero . so is the absolute value of a greater than the absolute value of b ? well , no . absolute value of a is to the left of the absolute value of b on our number line . it is less than the absolute value of b . so this is not true . all right , next statement . `` absolute value of a is less than the absolute value of c. '' well , we already know that the absolute value of a is the same value as c. so what 's the absolute value of c ? well , the absolute value of a positive number is just going to be that number . so this point right over here is also the absolute value of c. so we see that the absolute value of a is equal to the absolute value of c. it 's not less than . so we are going to mark that off . we could have written , `` absolute value of a is equal to absolute value of c. '' that would have been true . all right , last one . a is less than c. well , once again a is to the left of c on the number line . so that is true , because our number line is increasing as we go from left to right . if one number is to the left of another number , it is less than the other number . so a is indeed less than c. and we are done .
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we could have written , `` absolute value of a is equal to absolute value of c. '' that would have been true . all right , last one . a is less than c. well , once again a is to the left of c on the number line .
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why does an absolute value , have the two lines ( one on the left and one on the right ) ?
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what i have here are three numbers plotted on the number line . we have the number a , the number c , the number b . and then we have three -- ( laughs ) we have four inequalities , actually . four inequalities that involve absolute value . and what i want to do is figure out which is these inequalities are true , given where a , c and b are on the number line . and i encourage you to pause the video and try to think through it on your own . all right , let 's look at this first one . it says that , `` a is less than b . '' so if we look at a and we look at b , a is clearly to the left of b on the number line . so we know that this is true . even more we know that a is negative , it 's to the left of zero , while b is positive . which is , if one thing is negative and the other thing is positive , the negative thing is definitely going to be less than the positive thing . but even easier than that , a is to the left of b on the number line . if you 're to the left of something else on the number line you 're less than that other thing . because the number line , at least the way we 've constructed it , it increases from left to right . all right , the next statement , `` the absolute value of a is greater than the absolute value of b . '' well , let 's just think about where these are on the number line . so we 've already said a is three hash marks to the left of zero . that is a . so what is going to be the absolute value of a ? well , the absolute value of a is the distance that a is from zero . so the distance that a is from zero is one , two , three hash marks . so the absolute value of a is just going to be that same distance on the positive side . so the point that we marked as c is also the absolute value of a . so that is also the absolute value of a . the absolute value of a -- sorry , a is three to the left of zero . absolute value of a is going to be three to the right . it 's just a measure of , how many hash marks is it from zero ? well , it 's three hash marks from zero so we put it right over here . so is the absolute value of a greater than the absolute value of b ? or what 's the absolute value of b ? well , b is one , two , three , four , five , six , seven , eight hash marks to the right of zero . and so the absolute value of b is going to be on the eighth hash mark . because it 's eight hash marks to the right . so this is also the absolute value of b . and this is consistent with what we 've learned about absolute value . absolute value of a positive number is just going to be that number again . absolute value of a negative number is going to be the opposite of that number . and absolute value of zero is just going to be zero . so is the absolute value of a greater than the absolute value of b ? well , no . absolute value of a is to the left of the absolute value of b on our number line . it is less than the absolute value of b . so this is not true . all right , next statement . `` absolute value of a is less than the absolute value of c. '' well , we already know that the absolute value of a is the same value as c. so what 's the absolute value of c ? well , the absolute value of a positive number is just going to be that number . so this point right over here is also the absolute value of c. so we see that the absolute value of a is equal to the absolute value of c. it 's not less than . so we are going to mark that off . we could have written , `` absolute value of a is equal to absolute value of c. '' that would have been true . all right , last one . a is less than c. well , once again a is to the left of c on the number line . so that is true , because our number line is increasing as we go from left to right . if one number is to the left of another number , it is less than the other number . so a is indeed less than c. and we are done .
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all right , next statement . `` absolute value of a is less than the absolute value of c. '' well , we already know that the absolute value of a is the same value as c. so what 's the absolute value of c ? well , the absolute value of a positive number is just going to be that number .
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what does absolute value mean ?
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to understand the labs of septic shock , let 's first go ahead and recall what septic shock is . so really briefly , remember , septic shock is an infective material that you see in blood vessels . white blood cells amount a response to the septic material . in amounting a response , they release all these different immune molecules that can cause damage to blood vessels and increase blood vessel diameter , and the permeability of blood vessels , and so on and so forth . what 's the first thing you think you would want to do in a patient who might have shock ? well first of all , we want to diagnose it , right ? so what can we do to diagnose shock ? well we have a couple of lab tests that we can use . the first thing you want to do is check what 's going on . a patient comes in who has fevers , chills , they 're sweating , they 're very flushed . you notice that their blood pressure is dropping . so you 're thinking , maybe septic shock . so the first thing you want to do is , aside from checking their temperature and checking their vital signs , is you want to check maybe they have an infection in their blood . maybe there 's infective material in their blood . so you can do that by getting blood cultures . because you want to grow out whatever is in the blood and see if it 's a fungus or bacteria or a virus . so blood cultures will allow you to figure out what organism is in the bloodstream . next , you should probably figure out how severe the shock is , and if it is in fact shock . are the organs damaged ? what 's going on ? you 'll get values such as lactic acid or serum lactate . serum lactate is important because it shows you tissue perfusion , when cells of the body are no longer getting oxygen . so these little orange boxes are cells . when these guys are not longer getting oxygen , they have to resort through another way to produce energy . that other way is anaerobic metabolism , metabolism without oxygen . a byproduct of that is lactate , or lactic acid . so measuring the levels of serum lactate will tell you just how oxygen-starved these cells are . next , you can also get an abg , or an arterial blood gas . that will tell you how much oxygen is in the blood . it will also tell you other things like the carbon dioxide , different blood gases . and then you 'll get some other lab tests that are maybe organ specific . so , for example , you might want to get a bun or a creatinine . these are specific tests for the kidney . i 'm only going to write down these tests for the kidney , but you might want to get the other tests for other organs as well . now , the lab values for the kidney are especially important because if the kidneys are deprived from oxygen for just a little while , they can actually be damaged . so they 're more readily injured by lack of oxygen . so these are good labs to get . now , once all these labs are in the work , the next logical step is to immediately treat this patient . treatment is associated with mortality . the sooner the patient is treated , the more likely it is that they will survive . so they 'll have decreased mortality if they 're treated more quickly . the treatment usually starts with just very broad spectrum antibiotics . broad spectrum antibiotics . now , why broad spectrum ? well , when you first treat sepsis , you 'll have drawn a blood culture , but you wo n't have the results back yet . so you 'll have to start with an antibiotic that can treat many different types of infections . gram-positives , gram-negatives . many different types of bacteria . if the patient does not really get better with broad-spectrum antibiotics , use of anti-fungals may also be indicated , because it could be a fungal infection . usually you start here . broad-spectrum antibiotics . then you 'll check the blood cultures afterwards . once those cultures return , the patient can be switched to a more tailored antiobiotic therapy to provide an antibiotic or an antimicrobial that the organism is susceptible to . now remember , not only is there an infection going on , but as a byproduct of this infection , the patient has a drop in blood pressure . so , treatment will also include iv fluids to restore blood pressure , as well as a medication called pressors . what pressors do is they help squeeze down blood vessels to allow an increase in systemic vascular resistance , or resistance of blood vessels , which helps restore the blood pressure as well . so , both of these will increase blood pressure . so treatment will likely take days to weeks . in the meantime , while the patient is recovering , what do you think the next logical step is ? you know , the patient has been diagnosed with septic shock , they 're being treated for it . so the next step is really to see how the progress of the patient is . what 's the progress of the infection ? to check the progress , you know , you might continue to get lactate , abg , bun and creatinine to monitor the patient , but you can also get other labs such as a crp or an esr . now crp stand for c-reactive protein and esr stands for erythrocyte sedimentation rate . really , the names of these are somewhat inconsequential . the main idea here is you can track inflammation . so these allow you to track inflammation . when a patient is first diagnosed with septic shock , these values are going to be very elevated . possibly up around 100 . each of these . just to give you an idea , the normal value of crp should be less than one milligram per deciliter , and the normal esr really depends on age . it will be probably below 20 or maybe 25 millimeters per hour . that 's the units of esr , erythrocyte sedimentation rate . so crp and esr , as i was saying , may be drastically elevated . so resolution of septic shock will show these values starting to go back down to normal , so searching for a down trend of these elevated lab values . so really that 's it with septic shock . it all makes sense based off of what 's going on . infective material in the bloodstream . let me make a couple final points . you 'll always want to start with blood cultures before you do antibiotic therapy . this is very important so that the organism in the patient 's bloodstream can be discovered . if broad-spectrum antibiotics are started before blood cultures are obtained , you know there will be antibiotics in the blood . so when a lab technician goes to culture it , those antibiotics might interfere with the growth of the blood cultures . so always blood cultures first , and then antibiotics . but also , another great thing to note is these should not be delayed . because remember , delay in treatment can lead to increased mortality . and last of all , in many hospitals you might hear the term , two large bore iv lines for iv fluid treatment . essentially , that 's establishing two lines in either arm in which fluids can get to the patient . they 'll be called large bore because they 'll be very large in diameter . these tubes will have a very large diameter . this allows for iv fluid to get to the patient quicker so that blood pressure can be increased very quickly . so remember the steps . diagnosis , treatment , and then tracking progression of septic shock .
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it will be probably below 20 or maybe 25 millimeters per hour . that 's the units of esr , erythrocyte sedimentation rate . so crp and esr , as i was saying , may be drastically elevated . so resolution of septic shock will show these values starting to go back down to normal , so searching for a down trend of these elevated lab values .
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why the esr is elevated ?
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to understand the labs of septic shock , let 's first go ahead and recall what septic shock is . so really briefly , remember , septic shock is an infective material that you see in blood vessels . white blood cells amount a response to the septic material . in amounting a response , they release all these different immune molecules that can cause damage to blood vessels and increase blood vessel diameter , and the permeability of blood vessels , and so on and so forth . what 's the first thing you think you would want to do in a patient who might have shock ? well first of all , we want to diagnose it , right ? so what can we do to diagnose shock ? well we have a couple of lab tests that we can use . the first thing you want to do is check what 's going on . a patient comes in who has fevers , chills , they 're sweating , they 're very flushed . you notice that their blood pressure is dropping . so you 're thinking , maybe septic shock . so the first thing you want to do is , aside from checking their temperature and checking their vital signs , is you want to check maybe they have an infection in their blood . maybe there 's infective material in their blood . so you can do that by getting blood cultures . because you want to grow out whatever is in the blood and see if it 's a fungus or bacteria or a virus . so blood cultures will allow you to figure out what organism is in the bloodstream . next , you should probably figure out how severe the shock is , and if it is in fact shock . are the organs damaged ? what 's going on ? you 'll get values such as lactic acid or serum lactate . serum lactate is important because it shows you tissue perfusion , when cells of the body are no longer getting oxygen . so these little orange boxes are cells . when these guys are not longer getting oxygen , they have to resort through another way to produce energy . that other way is anaerobic metabolism , metabolism without oxygen . a byproduct of that is lactate , or lactic acid . so measuring the levels of serum lactate will tell you just how oxygen-starved these cells are . next , you can also get an abg , or an arterial blood gas . that will tell you how much oxygen is in the blood . it will also tell you other things like the carbon dioxide , different blood gases . and then you 'll get some other lab tests that are maybe organ specific . so , for example , you might want to get a bun or a creatinine . these are specific tests for the kidney . i 'm only going to write down these tests for the kidney , but you might want to get the other tests for other organs as well . now , the lab values for the kidney are especially important because if the kidneys are deprived from oxygen for just a little while , they can actually be damaged . so they 're more readily injured by lack of oxygen . so these are good labs to get . now , once all these labs are in the work , the next logical step is to immediately treat this patient . treatment is associated with mortality . the sooner the patient is treated , the more likely it is that they will survive . so they 'll have decreased mortality if they 're treated more quickly . the treatment usually starts with just very broad spectrum antibiotics . broad spectrum antibiotics . now , why broad spectrum ? well , when you first treat sepsis , you 'll have drawn a blood culture , but you wo n't have the results back yet . so you 'll have to start with an antibiotic that can treat many different types of infections . gram-positives , gram-negatives . many different types of bacteria . if the patient does not really get better with broad-spectrum antibiotics , use of anti-fungals may also be indicated , because it could be a fungal infection . usually you start here . broad-spectrum antibiotics . then you 'll check the blood cultures afterwards . once those cultures return , the patient can be switched to a more tailored antiobiotic therapy to provide an antibiotic or an antimicrobial that the organism is susceptible to . now remember , not only is there an infection going on , but as a byproduct of this infection , the patient has a drop in blood pressure . so , treatment will also include iv fluids to restore blood pressure , as well as a medication called pressors . what pressors do is they help squeeze down blood vessels to allow an increase in systemic vascular resistance , or resistance of blood vessels , which helps restore the blood pressure as well . so , both of these will increase blood pressure . so treatment will likely take days to weeks . in the meantime , while the patient is recovering , what do you think the next logical step is ? you know , the patient has been diagnosed with septic shock , they 're being treated for it . so the next step is really to see how the progress of the patient is . what 's the progress of the infection ? to check the progress , you know , you might continue to get lactate , abg , bun and creatinine to monitor the patient , but you can also get other labs such as a crp or an esr . now crp stand for c-reactive protein and esr stands for erythrocyte sedimentation rate . really , the names of these are somewhat inconsequential . the main idea here is you can track inflammation . so these allow you to track inflammation . when a patient is first diagnosed with septic shock , these values are going to be very elevated . possibly up around 100 . each of these . just to give you an idea , the normal value of crp should be less than one milligram per deciliter , and the normal esr really depends on age . it will be probably below 20 or maybe 25 millimeters per hour . that 's the units of esr , erythrocyte sedimentation rate . so crp and esr , as i was saying , may be drastically elevated . so resolution of septic shock will show these values starting to go back down to normal , so searching for a down trend of these elevated lab values . so really that 's it with septic shock . it all makes sense based off of what 's going on . infective material in the bloodstream . let me make a couple final points . you 'll always want to start with blood cultures before you do antibiotic therapy . this is very important so that the organism in the patient 's bloodstream can be discovered . if broad-spectrum antibiotics are started before blood cultures are obtained , you know there will be antibiotics in the blood . so when a lab technician goes to culture it , those antibiotics might interfere with the growth of the blood cultures . so always blood cultures first , and then antibiotics . but also , another great thing to note is these should not be delayed . because remember , delay in treatment can lead to increased mortality . and last of all , in many hospitals you might hear the term , two large bore iv lines for iv fluid treatment . essentially , that 's establishing two lines in either arm in which fluids can get to the patient . they 'll be called large bore because they 'll be very large in diameter . these tubes will have a very large diameter . this allows for iv fluid to get to the patient quicker so that blood pressure can be increased very quickly . so remember the steps . diagnosis , treatment , and then tracking progression of septic shock .
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now , why broad spectrum ? well , when you first treat sepsis , you 'll have drawn a blood culture , but you wo n't have the results back yet . so you 'll have to start with an antibiotic that can treat many different types of infections .
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should n't you give the patients fluids and ionotrops first and circulatory and respiratory resuscitation ?
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to understand the labs of septic shock , let 's first go ahead and recall what septic shock is . so really briefly , remember , septic shock is an infective material that you see in blood vessels . white blood cells amount a response to the septic material . in amounting a response , they release all these different immune molecules that can cause damage to blood vessels and increase blood vessel diameter , and the permeability of blood vessels , and so on and so forth . what 's the first thing you think you would want to do in a patient who might have shock ? well first of all , we want to diagnose it , right ? so what can we do to diagnose shock ? well we have a couple of lab tests that we can use . the first thing you want to do is check what 's going on . a patient comes in who has fevers , chills , they 're sweating , they 're very flushed . you notice that their blood pressure is dropping . so you 're thinking , maybe septic shock . so the first thing you want to do is , aside from checking their temperature and checking their vital signs , is you want to check maybe they have an infection in their blood . maybe there 's infective material in their blood . so you can do that by getting blood cultures . because you want to grow out whatever is in the blood and see if it 's a fungus or bacteria or a virus . so blood cultures will allow you to figure out what organism is in the bloodstream . next , you should probably figure out how severe the shock is , and if it is in fact shock . are the organs damaged ? what 's going on ? you 'll get values such as lactic acid or serum lactate . serum lactate is important because it shows you tissue perfusion , when cells of the body are no longer getting oxygen . so these little orange boxes are cells . when these guys are not longer getting oxygen , they have to resort through another way to produce energy . that other way is anaerobic metabolism , metabolism without oxygen . a byproduct of that is lactate , or lactic acid . so measuring the levels of serum lactate will tell you just how oxygen-starved these cells are . next , you can also get an abg , or an arterial blood gas . that will tell you how much oxygen is in the blood . it will also tell you other things like the carbon dioxide , different blood gases . and then you 'll get some other lab tests that are maybe organ specific . so , for example , you might want to get a bun or a creatinine . these are specific tests for the kidney . i 'm only going to write down these tests for the kidney , but you might want to get the other tests for other organs as well . now , the lab values for the kidney are especially important because if the kidneys are deprived from oxygen for just a little while , they can actually be damaged . so they 're more readily injured by lack of oxygen . so these are good labs to get . now , once all these labs are in the work , the next logical step is to immediately treat this patient . treatment is associated with mortality . the sooner the patient is treated , the more likely it is that they will survive . so they 'll have decreased mortality if they 're treated more quickly . the treatment usually starts with just very broad spectrum antibiotics . broad spectrum antibiotics . now , why broad spectrum ? well , when you first treat sepsis , you 'll have drawn a blood culture , but you wo n't have the results back yet . so you 'll have to start with an antibiotic that can treat many different types of infections . gram-positives , gram-negatives . many different types of bacteria . if the patient does not really get better with broad-spectrum antibiotics , use of anti-fungals may also be indicated , because it could be a fungal infection . usually you start here . broad-spectrum antibiotics . then you 'll check the blood cultures afterwards . once those cultures return , the patient can be switched to a more tailored antiobiotic therapy to provide an antibiotic or an antimicrobial that the organism is susceptible to . now remember , not only is there an infection going on , but as a byproduct of this infection , the patient has a drop in blood pressure . so , treatment will also include iv fluids to restore blood pressure , as well as a medication called pressors . what pressors do is they help squeeze down blood vessels to allow an increase in systemic vascular resistance , or resistance of blood vessels , which helps restore the blood pressure as well . so , both of these will increase blood pressure . so treatment will likely take days to weeks . in the meantime , while the patient is recovering , what do you think the next logical step is ? you know , the patient has been diagnosed with septic shock , they 're being treated for it . so the next step is really to see how the progress of the patient is . what 's the progress of the infection ? to check the progress , you know , you might continue to get lactate , abg , bun and creatinine to monitor the patient , but you can also get other labs such as a crp or an esr . now crp stand for c-reactive protein and esr stands for erythrocyte sedimentation rate . really , the names of these are somewhat inconsequential . the main idea here is you can track inflammation . so these allow you to track inflammation . when a patient is first diagnosed with septic shock , these values are going to be very elevated . possibly up around 100 . each of these . just to give you an idea , the normal value of crp should be less than one milligram per deciliter , and the normal esr really depends on age . it will be probably below 20 or maybe 25 millimeters per hour . that 's the units of esr , erythrocyte sedimentation rate . so crp and esr , as i was saying , may be drastically elevated . so resolution of septic shock will show these values starting to go back down to normal , so searching for a down trend of these elevated lab values . so really that 's it with septic shock . it all makes sense based off of what 's going on . infective material in the bloodstream . let me make a couple final points . you 'll always want to start with blood cultures before you do antibiotic therapy . this is very important so that the organism in the patient 's bloodstream can be discovered . if broad-spectrum antibiotics are started before blood cultures are obtained , you know there will be antibiotics in the blood . so when a lab technician goes to culture it , those antibiotics might interfere with the growth of the blood cultures . so always blood cultures first , and then antibiotics . but also , another great thing to note is these should not be delayed . because remember , delay in treatment can lead to increased mortality . and last of all , in many hospitals you might hear the term , two large bore iv lines for iv fluid treatment . essentially , that 's establishing two lines in either arm in which fluids can get to the patient . they 'll be called large bore because they 'll be very large in diameter . these tubes will have a very large diameter . this allows for iv fluid to get to the patient quicker so that blood pressure can be increased very quickly . so remember the steps . diagnosis , treatment , and then tracking progression of septic shock .
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that other way is anaerobic metabolism , metabolism without oxygen . a byproduct of that is lactate , or lactic acid . so measuring the levels of serum lactate will tell you just how oxygen-starved these cells are .
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could drawing a lactic acid/lactate for lab be thrown off by a person that has exercised recently ?
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to understand the labs of septic shock , let 's first go ahead and recall what septic shock is . so really briefly , remember , septic shock is an infective material that you see in blood vessels . white blood cells amount a response to the septic material . in amounting a response , they release all these different immune molecules that can cause damage to blood vessels and increase blood vessel diameter , and the permeability of blood vessels , and so on and so forth . what 's the first thing you think you would want to do in a patient who might have shock ? well first of all , we want to diagnose it , right ? so what can we do to diagnose shock ? well we have a couple of lab tests that we can use . the first thing you want to do is check what 's going on . a patient comes in who has fevers , chills , they 're sweating , they 're very flushed . you notice that their blood pressure is dropping . so you 're thinking , maybe septic shock . so the first thing you want to do is , aside from checking their temperature and checking their vital signs , is you want to check maybe they have an infection in their blood . maybe there 's infective material in their blood . so you can do that by getting blood cultures . because you want to grow out whatever is in the blood and see if it 's a fungus or bacteria or a virus . so blood cultures will allow you to figure out what organism is in the bloodstream . next , you should probably figure out how severe the shock is , and if it is in fact shock . are the organs damaged ? what 's going on ? you 'll get values such as lactic acid or serum lactate . serum lactate is important because it shows you tissue perfusion , when cells of the body are no longer getting oxygen . so these little orange boxes are cells . when these guys are not longer getting oxygen , they have to resort through another way to produce energy . that other way is anaerobic metabolism , metabolism without oxygen . a byproduct of that is lactate , or lactic acid . so measuring the levels of serum lactate will tell you just how oxygen-starved these cells are . next , you can also get an abg , or an arterial blood gas . that will tell you how much oxygen is in the blood . it will also tell you other things like the carbon dioxide , different blood gases . and then you 'll get some other lab tests that are maybe organ specific . so , for example , you might want to get a bun or a creatinine . these are specific tests for the kidney . i 'm only going to write down these tests for the kidney , but you might want to get the other tests for other organs as well . now , the lab values for the kidney are especially important because if the kidneys are deprived from oxygen for just a little while , they can actually be damaged . so they 're more readily injured by lack of oxygen . so these are good labs to get . now , once all these labs are in the work , the next logical step is to immediately treat this patient . treatment is associated with mortality . the sooner the patient is treated , the more likely it is that they will survive . so they 'll have decreased mortality if they 're treated more quickly . the treatment usually starts with just very broad spectrum antibiotics . broad spectrum antibiotics . now , why broad spectrum ? well , when you first treat sepsis , you 'll have drawn a blood culture , but you wo n't have the results back yet . so you 'll have to start with an antibiotic that can treat many different types of infections . gram-positives , gram-negatives . many different types of bacteria . if the patient does not really get better with broad-spectrum antibiotics , use of anti-fungals may also be indicated , because it could be a fungal infection . usually you start here . broad-spectrum antibiotics . then you 'll check the blood cultures afterwards . once those cultures return , the patient can be switched to a more tailored antiobiotic therapy to provide an antibiotic or an antimicrobial that the organism is susceptible to . now remember , not only is there an infection going on , but as a byproduct of this infection , the patient has a drop in blood pressure . so , treatment will also include iv fluids to restore blood pressure , as well as a medication called pressors . what pressors do is they help squeeze down blood vessels to allow an increase in systemic vascular resistance , or resistance of blood vessels , which helps restore the blood pressure as well . so , both of these will increase blood pressure . so treatment will likely take days to weeks . in the meantime , while the patient is recovering , what do you think the next logical step is ? you know , the patient has been diagnosed with septic shock , they 're being treated for it . so the next step is really to see how the progress of the patient is . what 's the progress of the infection ? to check the progress , you know , you might continue to get lactate , abg , bun and creatinine to monitor the patient , but you can also get other labs such as a crp or an esr . now crp stand for c-reactive protein and esr stands for erythrocyte sedimentation rate . really , the names of these are somewhat inconsequential . the main idea here is you can track inflammation . so these allow you to track inflammation . when a patient is first diagnosed with septic shock , these values are going to be very elevated . possibly up around 100 . each of these . just to give you an idea , the normal value of crp should be less than one milligram per deciliter , and the normal esr really depends on age . it will be probably below 20 or maybe 25 millimeters per hour . that 's the units of esr , erythrocyte sedimentation rate . so crp and esr , as i was saying , may be drastically elevated . so resolution of septic shock will show these values starting to go back down to normal , so searching for a down trend of these elevated lab values . so really that 's it with septic shock . it all makes sense based off of what 's going on . infective material in the bloodstream . let me make a couple final points . you 'll always want to start with blood cultures before you do antibiotic therapy . this is very important so that the organism in the patient 's bloodstream can be discovered . if broad-spectrum antibiotics are started before blood cultures are obtained , you know there will be antibiotics in the blood . so when a lab technician goes to culture it , those antibiotics might interfere with the growth of the blood cultures . so always blood cultures first , and then antibiotics . but also , another great thing to note is these should not be delayed . because remember , delay in treatment can lead to increased mortality . and last of all , in many hospitals you might hear the term , two large bore iv lines for iv fluid treatment . essentially , that 's establishing two lines in either arm in which fluids can get to the patient . they 'll be called large bore because they 'll be very large in diameter . these tubes will have a very large diameter . this allows for iv fluid to get to the patient quicker so that blood pressure can be increased very quickly . so remember the steps . diagnosis , treatment , and then tracking progression of septic shock .
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that other way is anaerobic metabolism , metabolism without oxygen . a byproduct of that is lactate , or lactic acid . so measuring the levels of serum lactate will tell you just how oxygen-starved these cells are .
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if so , how long would they have from the time of exercise to the time that the lactic acid is drawn for lab for it to not have any effect ?
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to understand the labs of septic shock , let 's first go ahead and recall what septic shock is . so really briefly , remember , septic shock is an infective material that you see in blood vessels . white blood cells amount a response to the septic material . in amounting a response , they release all these different immune molecules that can cause damage to blood vessels and increase blood vessel diameter , and the permeability of blood vessels , and so on and so forth . what 's the first thing you think you would want to do in a patient who might have shock ? well first of all , we want to diagnose it , right ? so what can we do to diagnose shock ? well we have a couple of lab tests that we can use . the first thing you want to do is check what 's going on . a patient comes in who has fevers , chills , they 're sweating , they 're very flushed . you notice that their blood pressure is dropping . so you 're thinking , maybe septic shock . so the first thing you want to do is , aside from checking their temperature and checking their vital signs , is you want to check maybe they have an infection in their blood . maybe there 's infective material in their blood . so you can do that by getting blood cultures . because you want to grow out whatever is in the blood and see if it 's a fungus or bacteria or a virus . so blood cultures will allow you to figure out what organism is in the bloodstream . next , you should probably figure out how severe the shock is , and if it is in fact shock . are the organs damaged ? what 's going on ? you 'll get values such as lactic acid or serum lactate . serum lactate is important because it shows you tissue perfusion , when cells of the body are no longer getting oxygen . so these little orange boxes are cells . when these guys are not longer getting oxygen , they have to resort through another way to produce energy . that other way is anaerobic metabolism , metabolism without oxygen . a byproduct of that is lactate , or lactic acid . so measuring the levels of serum lactate will tell you just how oxygen-starved these cells are . next , you can also get an abg , or an arterial blood gas . that will tell you how much oxygen is in the blood . it will also tell you other things like the carbon dioxide , different blood gases . and then you 'll get some other lab tests that are maybe organ specific . so , for example , you might want to get a bun or a creatinine . these are specific tests for the kidney . i 'm only going to write down these tests for the kidney , but you might want to get the other tests for other organs as well . now , the lab values for the kidney are especially important because if the kidneys are deprived from oxygen for just a little while , they can actually be damaged . so they 're more readily injured by lack of oxygen . so these are good labs to get . now , once all these labs are in the work , the next logical step is to immediately treat this patient . treatment is associated with mortality . the sooner the patient is treated , the more likely it is that they will survive . so they 'll have decreased mortality if they 're treated more quickly . the treatment usually starts with just very broad spectrum antibiotics . broad spectrum antibiotics . now , why broad spectrum ? well , when you first treat sepsis , you 'll have drawn a blood culture , but you wo n't have the results back yet . so you 'll have to start with an antibiotic that can treat many different types of infections . gram-positives , gram-negatives . many different types of bacteria . if the patient does not really get better with broad-spectrum antibiotics , use of anti-fungals may also be indicated , because it could be a fungal infection . usually you start here . broad-spectrum antibiotics . then you 'll check the blood cultures afterwards . once those cultures return , the patient can be switched to a more tailored antiobiotic therapy to provide an antibiotic or an antimicrobial that the organism is susceptible to . now remember , not only is there an infection going on , but as a byproduct of this infection , the patient has a drop in blood pressure . so , treatment will also include iv fluids to restore blood pressure , as well as a medication called pressors . what pressors do is they help squeeze down blood vessels to allow an increase in systemic vascular resistance , or resistance of blood vessels , which helps restore the blood pressure as well . so , both of these will increase blood pressure . so treatment will likely take days to weeks . in the meantime , while the patient is recovering , what do you think the next logical step is ? you know , the patient has been diagnosed with septic shock , they 're being treated for it . so the next step is really to see how the progress of the patient is . what 's the progress of the infection ? to check the progress , you know , you might continue to get lactate , abg , bun and creatinine to monitor the patient , but you can also get other labs such as a crp or an esr . now crp stand for c-reactive protein and esr stands for erythrocyte sedimentation rate . really , the names of these are somewhat inconsequential . the main idea here is you can track inflammation . so these allow you to track inflammation . when a patient is first diagnosed with septic shock , these values are going to be very elevated . possibly up around 100 . each of these . just to give you an idea , the normal value of crp should be less than one milligram per deciliter , and the normal esr really depends on age . it will be probably below 20 or maybe 25 millimeters per hour . that 's the units of esr , erythrocyte sedimentation rate . so crp and esr , as i was saying , may be drastically elevated . so resolution of septic shock will show these values starting to go back down to normal , so searching for a down trend of these elevated lab values . so really that 's it with septic shock . it all makes sense based off of what 's going on . infective material in the bloodstream . let me make a couple final points . you 'll always want to start with blood cultures before you do antibiotic therapy . this is very important so that the organism in the patient 's bloodstream can be discovered . if broad-spectrum antibiotics are started before blood cultures are obtained , you know there will be antibiotics in the blood . so when a lab technician goes to culture it , those antibiotics might interfere with the growth of the blood cultures . so always blood cultures first , and then antibiotics . but also , another great thing to note is these should not be delayed . because remember , delay in treatment can lead to increased mortality . and last of all , in many hospitals you might hear the term , two large bore iv lines for iv fluid treatment . essentially , that 's establishing two lines in either arm in which fluids can get to the patient . they 'll be called large bore because they 'll be very large in diameter . these tubes will have a very large diameter . this allows for iv fluid to get to the patient quicker so that blood pressure can be increased very quickly . so remember the steps . diagnosis , treatment , and then tracking progression of septic shock .
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to understand the labs of septic shock , let 's first go ahead and recall what septic shock is . so really briefly , remember , septic shock is an infective material that you see in blood vessels . white blood cells amount a response to the septic material .
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what if someone with septic shock has that because of a virus ?
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to understand the labs of septic shock , let 's first go ahead and recall what septic shock is . so really briefly , remember , septic shock is an infective material that you see in blood vessels . white blood cells amount a response to the septic material . in amounting a response , they release all these different immune molecules that can cause damage to blood vessels and increase blood vessel diameter , and the permeability of blood vessels , and so on and so forth . what 's the first thing you think you would want to do in a patient who might have shock ? well first of all , we want to diagnose it , right ? so what can we do to diagnose shock ? well we have a couple of lab tests that we can use . the first thing you want to do is check what 's going on . a patient comes in who has fevers , chills , they 're sweating , they 're very flushed . you notice that their blood pressure is dropping . so you 're thinking , maybe septic shock . so the first thing you want to do is , aside from checking their temperature and checking their vital signs , is you want to check maybe they have an infection in their blood . maybe there 's infective material in their blood . so you can do that by getting blood cultures . because you want to grow out whatever is in the blood and see if it 's a fungus or bacteria or a virus . so blood cultures will allow you to figure out what organism is in the bloodstream . next , you should probably figure out how severe the shock is , and if it is in fact shock . are the organs damaged ? what 's going on ? you 'll get values such as lactic acid or serum lactate . serum lactate is important because it shows you tissue perfusion , when cells of the body are no longer getting oxygen . so these little orange boxes are cells . when these guys are not longer getting oxygen , they have to resort through another way to produce energy . that other way is anaerobic metabolism , metabolism without oxygen . a byproduct of that is lactate , or lactic acid . so measuring the levels of serum lactate will tell you just how oxygen-starved these cells are . next , you can also get an abg , or an arterial blood gas . that will tell you how much oxygen is in the blood . it will also tell you other things like the carbon dioxide , different blood gases . and then you 'll get some other lab tests that are maybe organ specific . so , for example , you might want to get a bun or a creatinine . these are specific tests for the kidney . i 'm only going to write down these tests for the kidney , but you might want to get the other tests for other organs as well . now , the lab values for the kidney are especially important because if the kidneys are deprived from oxygen for just a little while , they can actually be damaged . so they 're more readily injured by lack of oxygen . so these are good labs to get . now , once all these labs are in the work , the next logical step is to immediately treat this patient . treatment is associated with mortality . the sooner the patient is treated , the more likely it is that they will survive . so they 'll have decreased mortality if they 're treated more quickly . the treatment usually starts with just very broad spectrum antibiotics . broad spectrum antibiotics . now , why broad spectrum ? well , when you first treat sepsis , you 'll have drawn a blood culture , but you wo n't have the results back yet . so you 'll have to start with an antibiotic that can treat many different types of infections . gram-positives , gram-negatives . many different types of bacteria . if the patient does not really get better with broad-spectrum antibiotics , use of anti-fungals may also be indicated , because it could be a fungal infection . usually you start here . broad-spectrum antibiotics . then you 'll check the blood cultures afterwards . once those cultures return , the patient can be switched to a more tailored antiobiotic therapy to provide an antibiotic or an antimicrobial that the organism is susceptible to . now remember , not only is there an infection going on , but as a byproduct of this infection , the patient has a drop in blood pressure . so , treatment will also include iv fluids to restore blood pressure , as well as a medication called pressors . what pressors do is they help squeeze down blood vessels to allow an increase in systemic vascular resistance , or resistance of blood vessels , which helps restore the blood pressure as well . so , both of these will increase blood pressure . so treatment will likely take days to weeks . in the meantime , while the patient is recovering , what do you think the next logical step is ? you know , the patient has been diagnosed with septic shock , they 're being treated for it . so the next step is really to see how the progress of the patient is . what 's the progress of the infection ? to check the progress , you know , you might continue to get lactate , abg , bun and creatinine to monitor the patient , but you can also get other labs such as a crp or an esr . now crp stand for c-reactive protein and esr stands for erythrocyte sedimentation rate . really , the names of these are somewhat inconsequential . the main idea here is you can track inflammation . so these allow you to track inflammation . when a patient is first diagnosed with septic shock , these values are going to be very elevated . possibly up around 100 . each of these . just to give you an idea , the normal value of crp should be less than one milligram per deciliter , and the normal esr really depends on age . it will be probably below 20 or maybe 25 millimeters per hour . that 's the units of esr , erythrocyte sedimentation rate . so crp and esr , as i was saying , may be drastically elevated . so resolution of septic shock will show these values starting to go back down to normal , so searching for a down trend of these elevated lab values . so really that 's it with septic shock . it all makes sense based off of what 's going on . infective material in the bloodstream . let me make a couple final points . you 'll always want to start with blood cultures before you do antibiotic therapy . this is very important so that the organism in the patient 's bloodstream can be discovered . if broad-spectrum antibiotics are started before blood cultures are obtained , you know there will be antibiotics in the blood . so when a lab technician goes to culture it , those antibiotics might interfere with the growth of the blood cultures . so always blood cultures first , and then antibiotics . but also , another great thing to note is these should not be delayed . because remember , delay in treatment can lead to increased mortality . and last of all , in many hospitals you might hear the term , two large bore iv lines for iv fluid treatment . essentially , that 's establishing two lines in either arm in which fluids can get to the patient . they 'll be called large bore because they 'll be very large in diameter . these tubes will have a very large diameter . this allows for iv fluid to get to the patient quicker so that blood pressure can be increased very quickly . so remember the steps . diagnosis , treatment , and then tracking progression of septic shock .
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now remember , not only is there an infection going on , but as a byproduct of this infection , the patient has a drop in blood pressure . so , treatment will also include iv fluids to restore blood pressure , as well as a medication called pressors . what pressors do is they help squeeze down blood vessels to allow an increase in systemic vascular resistance , or resistance of blood vessels , which helps restore the blood pressure as well .
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would n't hypertonic fluids have this advantage of pulling those fluids from extracellular space to vascular bed , thus improving oxygenation , apart from just hypovolemia treatment ?
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to understand the labs of septic shock , let 's first go ahead and recall what septic shock is . so really briefly , remember , septic shock is an infective material that you see in blood vessels . white blood cells amount a response to the septic material . in amounting a response , they release all these different immune molecules that can cause damage to blood vessels and increase blood vessel diameter , and the permeability of blood vessels , and so on and so forth . what 's the first thing you think you would want to do in a patient who might have shock ? well first of all , we want to diagnose it , right ? so what can we do to diagnose shock ? well we have a couple of lab tests that we can use . the first thing you want to do is check what 's going on . a patient comes in who has fevers , chills , they 're sweating , they 're very flushed . you notice that their blood pressure is dropping . so you 're thinking , maybe septic shock . so the first thing you want to do is , aside from checking their temperature and checking their vital signs , is you want to check maybe they have an infection in their blood . maybe there 's infective material in their blood . so you can do that by getting blood cultures . because you want to grow out whatever is in the blood and see if it 's a fungus or bacteria or a virus . so blood cultures will allow you to figure out what organism is in the bloodstream . next , you should probably figure out how severe the shock is , and if it is in fact shock . are the organs damaged ? what 's going on ? you 'll get values such as lactic acid or serum lactate . serum lactate is important because it shows you tissue perfusion , when cells of the body are no longer getting oxygen . so these little orange boxes are cells . when these guys are not longer getting oxygen , they have to resort through another way to produce energy . that other way is anaerobic metabolism , metabolism without oxygen . a byproduct of that is lactate , or lactic acid . so measuring the levels of serum lactate will tell you just how oxygen-starved these cells are . next , you can also get an abg , or an arterial blood gas . that will tell you how much oxygen is in the blood . it will also tell you other things like the carbon dioxide , different blood gases . and then you 'll get some other lab tests that are maybe organ specific . so , for example , you might want to get a bun or a creatinine . these are specific tests for the kidney . i 'm only going to write down these tests for the kidney , but you might want to get the other tests for other organs as well . now , the lab values for the kidney are especially important because if the kidneys are deprived from oxygen for just a little while , they can actually be damaged . so they 're more readily injured by lack of oxygen . so these are good labs to get . now , once all these labs are in the work , the next logical step is to immediately treat this patient . treatment is associated with mortality . the sooner the patient is treated , the more likely it is that they will survive . so they 'll have decreased mortality if they 're treated more quickly . the treatment usually starts with just very broad spectrum antibiotics . broad spectrum antibiotics . now , why broad spectrum ? well , when you first treat sepsis , you 'll have drawn a blood culture , but you wo n't have the results back yet . so you 'll have to start with an antibiotic that can treat many different types of infections . gram-positives , gram-negatives . many different types of bacteria . if the patient does not really get better with broad-spectrum antibiotics , use of anti-fungals may also be indicated , because it could be a fungal infection . usually you start here . broad-spectrum antibiotics . then you 'll check the blood cultures afterwards . once those cultures return , the patient can be switched to a more tailored antiobiotic therapy to provide an antibiotic or an antimicrobial that the organism is susceptible to . now remember , not only is there an infection going on , but as a byproduct of this infection , the patient has a drop in blood pressure . so , treatment will also include iv fluids to restore blood pressure , as well as a medication called pressors . what pressors do is they help squeeze down blood vessels to allow an increase in systemic vascular resistance , or resistance of blood vessels , which helps restore the blood pressure as well . so , both of these will increase blood pressure . so treatment will likely take days to weeks . in the meantime , while the patient is recovering , what do you think the next logical step is ? you know , the patient has been diagnosed with septic shock , they 're being treated for it . so the next step is really to see how the progress of the patient is . what 's the progress of the infection ? to check the progress , you know , you might continue to get lactate , abg , bun and creatinine to monitor the patient , but you can also get other labs such as a crp or an esr . now crp stand for c-reactive protein and esr stands for erythrocyte sedimentation rate . really , the names of these are somewhat inconsequential . the main idea here is you can track inflammation . so these allow you to track inflammation . when a patient is first diagnosed with septic shock , these values are going to be very elevated . possibly up around 100 . each of these . just to give you an idea , the normal value of crp should be less than one milligram per deciliter , and the normal esr really depends on age . it will be probably below 20 or maybe 25 millimeters per hour . that 's the units of esr , erythrocyte sedimentation rate . so crp and esr , as i was saying , may be drastically elevated . so resolution of septic shock will show these values starting to go back down to normal , so searching for a down trend of these elevated lab values . so really that 's it with septic shock . it all makes sense based off of what 's going on . infective material in the bloodstream . let me make a couple final points . you 'll always want to start with blood cultures before you do antibiotic therapy . this is very important so that the organism in the patient 's bloodstream can be discovered . if broad-spectrum antibiotics are started before blood cultures are obtained , you know there will be antibiotics in the blood . so when a lab technician goes to culture it , those antibiotics might interfere with the growth of the blood cultures . so always blood cultures first , and then antibiotics . but also , another great thing to note is these should not be delayed . because remember , delay in treatment can lead to increased mortality . and last of all , in many hospitals you might hear the term , two large bore iv lines for iv fluid treatment . essentially , that 's establishing two lines in either arm in which fluids can get to the patient . they 'll be called large bore because they 'll be very large in diameter . these tubes will have a very large diameter . this allows for iv fluid to get to the patient quicker so that blood pressure can be increased very quickly . so remember the steps . diagnosis , treatment , and then tracking progression of septic shock .
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in amounting a response , they release all these different immune molecules that can cause damage to blood vessels and increase blood vessel diameter , and the permeability of blood vessels , and so on and so forth . what 's the first thing you think you would want to do in a patient who might have shock ? well first of all , we want to diagnose it , right ?
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would a patient experience any lasting mental/psychological problems ?
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to understand the labs of septic shock , let 's first go ahead and recall what septic shock is . so really briefly , remember , septic shock is an infective material that you see in blood vessels . white blood cells amount a response to the septic material . in amounting a response , they release all these different immune molecules that can cause damage to blood vessels and increase blood vessel diameter , and the permeability of blood vessels , and so on and so forth . what 's the first thing you think you would want to do in a patient who might have shock ? well first of all , we want to diagnose it , right ? so what can we do to diagnose shock ? well we have a couple of lab tests that we can use . the first thing you want to do is check what 's going on . a patient comes in who has fevers , chills , they 're sweating , they 're very flushed . you notice that their blood pressure is dropping . so you 're thinking , maybe septic shock . so the first thing you want to do is , aside from checking their temperature and checking their vital signs , is you want to check maybe they have an infection in their blood . maybe there 's infective material in their blood . so you can do that by getting blood cultures . because you want to grow out whatever is in the blood and see if it 's a fungus or bacteria or a virus . so blood cultures will allow you to figure out what organism is in the bloodstream . next , you should probably figure out how severe the shock is , and if it is in fact shock . are the organs damaged ? what 's going on ? you 'll get values such as lactic acid or serum lactate . serum lactate is important because it shows you tissue perfusion , when cells of the body are no longer getting oxygen . so these little orange boxes are cells . when these guys are not longer getting oxygen , they have to resort through another way to produce energy . that other way is anaerobic metabolism , metabolism without oxygen . a byproduct of that is lactate , or lactic acid . so measuring the levels of serum lactate will tell you just how oxygen-starved these cells are . next , you can also get an abg , or an arterial blood gas . that will tell you how much oxygen is in the blood . it will also tell you other things like the carbon dioxide , different blood gases . and then you 'll get some other lab tests that are maybe organ specific . so , for example , you might want to get a bun or a creatinine . these are specific tests for the kidney . i 'm only going to write down these tests for the kidney , but you might want to get the other tests for other organs as well . now , the lab values for the kidney are especially important because if the kidneys are deprived from oxygen for just a little while , they can actually be damaged . so they 're more readily injured by lack of oxygen . so these are good labs to get . now , once all these labs are in the work , the next logical step is to immediately treat this patient . treatment is associated with mortality . the sooner the patient is treated , the more likely it is that they will survive . so they 'll have decreased mortality if they 're treated more quickly . the treatment usually starts with just very broad spectrum antibiotics . broad spectrum antibiotics . now , why broad spectrum ? well , when you first treat sepsis , you 'll have drawn a blood culture , but you wo n't have the results back yet . so you 'll have to start with an antibiotic that can treat many different types of infections . gram-positives , gram-negatives . many different types of bacteria . if the patient does not really get better with broad-spectrum antibiotics , use of anti-fungals may also be indicated , because it could be a fungal infection . usually you start here . broad-spectrum antibiotics . then you 'll check the blood cultures afterwards . once those cultures return , the patient can be switched to a more tailored antiobiotic therapy to provide an antibiotic or an antimicrobial that the organism is susceptible to . now remember , not only is there an infection going on , but as a byproduct of this infection , the patient has a drop in blood pressure . so , treatment will also include iv fluids to restore blood pressure , as well as a medication called pressors . what pressors do is they help squeeze down blood vessels to allow an increase in systemic vascular resistance , or resistance of blood vessels , which helps restore the blood pressure as well . so , both of these will increase blood pressure . so treatment will likely take days to weeks . in the meantime , while the patient is recovering , what do you think the next logical step is ? you know , the patient has been diagnosed with septic shock , they 're being treated for it . so the next step is really to see how the progress of the patient is . what 's the progress of the infection ? to check the progress , you know , you might continue to get lactate , abg , bun and creatinine to monitor the patient , but you can also get other labs such as a crp or an esr . now crp stand for c-reactive protein and esr stands for erythrocyte sedimentation rate . really , the names of these are somewhat inconsequential . the main idea here is you can track inflammation . so these allow you to track inflammation . when a patient is first diagnosed with septic shock , these values are going to be very elevated . possibly up around 100 . each of these . just to give you an idea , the normal value of crp should be less than one milligram per deciliter , and the normal esr really depends on age . it will be probably below 20 or maybe 25 millimeters per hour . that 's the units of esr , erythrocyte sedimentation rate . so crp and esr , as i was saying , may be drastically elevated . so resolution of septic shock will show these values starting to go back down to normal , so searching for a down trend of these elevated lab values . so really that 's it with septic shock . it all makes sense based off of what 's going on . infective material in the bloodstream . let me make a couple final points . you 'll always want to start with blood cultures before you do antibiotic therapy . this is very important so that the organism in the patient 's bloodstream can be discovered . if broad-spectrum antibiotics are started before blood cultures are obtained , you know there will be antibiotics in the blood . so when a lab technician goes to culture it , those antibiotics might interfere with the growth of the blood cultures . so always blood cultures first , and then antibiotics . but also , another great thing to note is these should not be delayed . because remember , delay in treatment can lead to increased mortality . and last of all , in many hospitals you might hear the term , two large bore iv lines for iv fluid treatment . essentially , that 's establishing two lines in either arm in which fluids can get to the patient . they 'll be called large bore because they 'll be very large in diameter . these tubes will have a very large diameter . this allows for iv fluid to get to the patient quicker so that blood pressure can be increased very quickly . so remember the steps . diagnosis , treatment , and then tracking progression of septic shock .
|
to understand the labs of septic shock , let 's first go ahead and recall what septic shock is . so really briefly , remember , septic shock is an infective material that you see in blood vessels . white blood cells amount a response to the septic material .
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would some infections be more likely to cause septic shock ?
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to understand the labs of septic shock , let 's first go ahead and recall what septic shock is . so really briefly , remember , septic shock is an infective material that you see in blood vessels . white blood cells amount a response to the septic material . in amounting a response , they release all these different immune molecules that can cause damage to blood vessels and increase blood vessel diameter , and the permeability of blood vessels , and so on and so forth . what 's the first thing you think you would want to do in a patient who might have shock ? well first of all , we want to diagnose it , right ? so what can we do to diagnose shock ? well we have a couple of lab tests that we can use . the first thing you want to do is check what 's going on . a patient comes in who has fevers , chills , they 're sweating , they 're very flushed . you notice that their blood pressure is dropping . so you 're thinking , maybe septic shock . so the first thing you want to do is , aside from checking their temperature and checking their vital signs , is you want to check maybe they have an infection in their blood . maybe there 's infective material in their blood . so you can do that by getting blood cultures . because you want to grow out whatever is in the blood and see if it 's a fungus or bacteria or a virus . so blood cultures will allow you to figure out what organism is in the bloodstream . next , you should probably figure out how severe the shock is , and if it is in fact shock . are the organs damaged ? what 's going on ? you 'll get values such as lactic acid or serum lactate . serum lactate is important because it shows you tissue perfusion , when cells of the body are no longer getting oxygen . so these little orange boxes are cells . when these guys are not longer getting oxygen , they have to resort through another way to produce energy . that other way is anaerobic metabolism , metabolism without oxygen . a byproduct of that is lactate , or lactic acid . so measuring the levels of serum lactate will tell you just how oxygen-starved these cells are . next , you can also get an abg , or an arterial blood gas . that will tell you how much oxygen is in the blood . it will also tell you other things like the carbon dioxide , different blood gases . and then you 'll get some other lab tests that are maybe organ specific . so , for example , you might want to get a bun or a creatinine . these are specific tests for the kidney . i 'm only going to write down these tests for the kidney , but you might want to get the other tests for other organs as well . now , the lab values for the kidney are especially important because if the kidneys are deprived from oxygen for just a little while , they can actually be damaged . so they 're more readily injured by lack of oxygen . so these are good labs to get . now , once all these labs are in the work , the next logical step is to immediately treat this patient . treatment is associated with mortality . the sooner the patient is treated , the more likely it is that they will survive . so they 'll have decreased mortality if they 're treated more quickly . the treatment usually starts with just very broad spectrum antibiotics . broad spectrum antibiotics . now , why broad spectrum ? well , when you first treat sepsis , you 'll have drawn a blood culture , but you wo n't have the results back yet . so you 'll have to start with an antibiotic that can treat many different types of infections . gram-positives , gram-negatives . many different types of bacteria . if the patient does not really get better with broad-spectrum antibiotics , use of anti-fungals may also be indicated , because it could be a fungal infection . usually you start here . broad-spectrum antibiotics . then you 'll check the blood cultures afterwards . once those cultures return , the patient can be switched to a more tailored antiobiotic therapy to provide an antibiotic or an antimicrobial that the organism is susceptible to . now remember , not only is there an infection going on , but as a byproduct of this infection , the patient has a drop in blood pressure . so , treatment will also include iv fluids to restore blood pressure , as well as a medication called pressors . what pressors do is they help squeeze down blood vessels to allow an increase in systemic vascular resistance , or resistance of blood vessels , which helps restore the blood pressure as well . so , both of these will increase blood pressure . so treatment will likely take days to weeks . in the meantime , while the patient is recovering , what do you think the next logical step is ? you know , the patient has been diagnosed with septic shock , they 're being treated for it . so the next step is really to see how the progress of the patient is . what 's the progress of the infection ? to check the progress , you know , you might continue to get lactate , abg , bun and creatinine to monitor the patient , but you can also get other labs such as a crp or an esr . now crp stand for c-reactive protein and esr stands for erythrocyte sedimentation rate . really , the names of these are somewhat inconsequential . the main idea here is you can track inflammation . so these allow you to track inflammation . when a patient is first diagnosed with septic shock , these values are going to be very elevated . possibly up around 100 . each of these . just to give you an idea , the normal value of crp should be less than one milligram per deciliter , and the normal esr really depends on age . it will be probably below 20 or maybe 25 millimeters per hour . that 's the units of esr , erythrocyte sedimentation rate . so crp and esr , as i was saying , may be drastically elevated . so resolution of septic shock will show these values starting to go back down to normal , so searching for a down trend of these elevated lab values . so really that 's it with septic shock . it all makes sense based off of what 's going on . infective material in the bloodstream . let me make a couple final points . you 'll always want to start with blood cultures before you do antibiotic therapy . this is very important so that the organism in the patient 's bloodstream can be discovered . if broad-spectrum antibiotics are started before blood cultures are obtained , you know there will be antibiotics in the blood . so when a lab technician goes to culture it , those antibiotics might interfere with the growth of the blood cultures . so always blood cultures first , and then antibiotics . but also , another great thing to note is these should not be delayed . because remember , delay in treatment can lead to increased mortality . and last of all , in many hospitals you might hear the term , two large bore iv lines for iv fluid treatment . essentially , that 's establishing two lines in either arm in which fluids can get to the patient . they 'll be called large bore because they 'll be very large in diameter . these tubes will have a very large diameter . this allows for iv fluid to get to the patient quicker so that blood pressure can be increased very quickly . so remember the steps . diagnosis , treatment , and then tracking progression of septic shock .
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because remember , delay in treatment can lead to increased mortality . and last of all , in many hospitals you might hear the term , two large bore iv lines for iv fluid treatment . essentially , that 's establishing two lines in either arm in which fluids can get to the patient .
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then circulation would be addressed ( iv , meds etc ) ?
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( elegant music ) - [ beth ] we 're here in the maya galleries at the metropolitan museum of art , looking at a lintel of carved stone that would have been the horizontal piece over a doorway . - [ james ] the sculptor who carved this , actually carved the underside of the lintel , to be seen as you enter the temple or palace . you would have to look up , and the sculpture is carved in such low relief that you probably would have had to use a torchlight in order to make the figures appear . - [ beth ] this was not a building that anyone could have walked through . - [ james ] no , the maya palaces are very restricted in access , by different patios and courtyards and staircases . this would have been seen by a very important group of individuals . - [ beth ] and it features a very important royal figure . - [ james ] in the hieroglyphs above his head , he 's named as chel te ' chan k'inich , otherwise known as shield jaguar iv . the penultimate and last important ruler of of a kingdom at yaxchilan . - [ beth ] here we are during the classic period , and it 's coming to a close . - [ james ] shield jaguar iv was the last ruler to erect a lot of monuments in the area around yaxchilan . - [ beth ] here he is receiving important tribute , from the leader of a subservient city state . - [ james ] this lintel probably comes from a site we know as la pasadita , which is across the river from yaxchilan in modern day guatemala . the central figure handing gifts to the king is known as tiloom , an important subsidiary lord , in the yaxchilan kingdom . - [ beth ] in his left hand he is offering a fabulous headdress decorated with quetzal feathers , with jade , this very precious stone , and in his right hand likely some food or perhaps some incense . - [ james ] these are typical gifts in scenes of tribute , from these local lords to their over lords . - [ beth ] it looks to me as though tiloom is almost as well dressed as the king of yaxchilan . - [ james ] he 's very important , and that 's made clear by the artist in his central position in the composition , but also in his posture and size . he almost appears to be a little bit larger than the ruler himself . - [ beth ] he 's wearing a jade necklace with this pectoral decorated with a head . he 's got on a fabulous headdress himself of kilt . - [ james ] the garment that he 's wearing is very high quality , and you see this in yaxchilan courts , that the most important people wore this type of brocaded woven garment . - [ beth ] there 's another figure behind him , and we 're not quite sure who this figure is . - [ james ] he 's not named in the hieroglyphic text , but he holds a fan composed of quetzal feathers . he 's also part of this tribute event . - [ beth ] this is such an unusual relief because so much of the pigment survives giving us a good idea of how brightly painted these relief sculptures were . - [ james ] the red orange pigment is iron based , and the blue pigment is composed of indigo dye , mixed with minerals . - [ beth ] that blueish green was an important color , just like jade was an important stone for the maya . - [ james ] blue green was associated with jade , but also with water , and with agricultural fertility . - [ beth ] the stuff of life . - [ james ] the stuff of life . - [ beth ] i 'm struck by how naturalistically shield jaguar iv is represented . he 's seated in a cross legged position . he leans forward . it seems almost as if we can hear him speaking . - [ james ] yeah , he 's leaning forward . he 's probably addressing , or thanking the party in front of him for the gifts that they are bringing . - [ beth ] and below his throne we see a basket with some seeded fruit . also likely part of the offering . - [ james ] we often see maya lords surrounding themselves with tribute goods that often included foods like fruit or beans , even alcoholic beverages . - [ beth ] there 's something else that makes this particular carving so special , and that 's that we know the name of the artist . - [ james ] the only culture in the ancient americas in which artists signed their works was the classic maya , and this particular lintel was signed by its sculptor . his name was chakalte ' and he made at least three or four monuments during the reigns of bird jaguar iv , and shield jaguar iv at yaxchilan . - [ beth ] we get a sense of how important artists were at the maya court . - [ james ] absolutely , and the hypothesis would be that shield jaguar sent chakalte ' across the river to la pasadita to have tiloom project himself onto the lintel of a building they were constructing . - [ beth ] let 's talk for one moment about shield jaguar iv . he 's wearing this beaded necklace , but also a nose ornament . - [ james ] the large necklace that he 's wearing is known as a bar pectoral , which is a horizontal long tubular bead made of jade , and the nose ring is also probably a jade tube that is attached to the septum of the king . - [ beth ] we also see that he 's wearing bracelets . he 's heavily adorned . - [ james ] he is heavily adorned in jade and quetzal feathers which all share this blue green precious color , but a detail that is unusual to this lintel is that the throne itself is decorated with a lot of what look to be representations of jade beads and pendants . ( elegant music )
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( elegant music ) - [ beth ] we 're here in the maya galleries at the metropolitan museum of art , looking at a lintel of carved stone that would have been the horizontal piece over a doorway . - [ james ] the sculptor who carved this , actually carved the underside of the lintel , to be seen as you enter the temple or palace . you would have to look up , and the sculpture is carved in such low relief that you probably would have had to use a torchlight in order to make the figures appear .
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what is the name of the temple this lintel was found ?
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when i first started thinking about this video , i realized that asthma is going to be hard to talk about because so many people have it , everybody knows at least a little bit about it , so it might be hard to get really to the bottom of what really is asthma . so , to do this , let 's go all the way back from the beginning . let 's just start by talking about the lungs , and what they look like and what they do . so , we have here your big trachea , and they branch off into your left and right bronchi . those are the two main stems of the lungs . and from there , they keep branching off like branches on a tree , and they get smaller and smaller . there are countless levels . i 'm gon na just try to draw a few levels here for us . so they keep branching off like this , you get the idea . when we inspire , or when we breathe in , inhaling , it 's kind of like a vacuum cleaner sucking air in . and these are all the tubes that are connected to it . so this is like the big hose . if you can imagine your vacuum breaks down into little hoses , that 's basically what it looks like . so in our lungs oxygen goes in , when we breathe in . o2 is oxygen , two oxygens . and then on the reverse side when we breathe out , we breathe out carbon dioxide , which is the symbol as co2 , one carbon and two oxygens . now asthma is classified as an obstructive disease where air is blocked on the way out , breathing out co2 . but we 'll get to that later exactly where that happens . for now if we are just looking at the set of tubes , otherwise known as our airway , and anywhere we go , if we take a cut like this across any of the tubes and we look at it up the tube , or we look at what is called a cross section of it , then it 's going to look something like this . so we have a round shape for the outside of the tube . and then we have an opening . and in the middle here we call it the lumen . the lumen is just the inside of any tube . this is where air actually goes through . and here in the walls of the airway , we have connective tissue , we have glands , we have all kinds of things . but i want to talk about this smooth muscle layer here that 's around in the wall of the airway . so since it 's a muscle , then it can have force and change the shape of things around it . so in asthma , what we care about is that the smooth muscles can actually constrict this airway . so to see what that looks like , let me draw this again here . again , if this is the outside of the wall , then a person who has active asthma happening at the moment , their airway 's going to be smaller , the lumen is going to be smaller , maybe about , let 's say this big . and what has happened , is that the smooth muscle around it is contracting hard and is clamping down on that lumen . to make matters even worse , when our body 's inflamed , it secretes fluid . so into the lumen , which is usually supposed to be open and dry , we have extra fluid . so when the opening is already smaller , it 's being flooded by mucous and fluid . and this whole picture together is what asthma looks like in our airways . now i just showed you one tube here , because we cut it once here . but imagine this process is happening in all these vacuum tubes , all these little levels . so the air is really having trouble moving . actually , if you could imagine a vacuum . let me just draw one here . this is the very primitive model of our vacuum . and if you could imagine that this machine has a lot of power sucking air in , but when it 's coming out , it 's a passive process , so there 's no power pushing the air out . so even though this constriction here will make it harder to suck air in , but at least it has a motor behind it , as opposed to when the air 's coming out , it just has to passively leave through the smaller straws . so that makes it harder on the exhale . we 'll come back to what that sounds like when we listen with the stethoscope . but first , let 's talk about what causes this process . why would your airway suddenly clamp down like that ? why would our body allow it , and what triggers it ? so i promise that every time i talk about lungs , the first thing i will always say is , smoking . smoking can be a huge trigger for asthma . does n't even have to be firsthand smoke , it can be secondhand . in fact , kids who have asthma , they 're exposed to parents who smoke in the house . even parents who are smoking outside , but then wear the same clothes inside the house . that can trigger asthma , because these smoke particles are billions and billions of little things that do n't belong in the lungs , and when they 're in there , this process can happen . also because we live in a time where there 's so much machinery around us , this is a car if you can tell ... so car exhaust and pollution in general in the cities can be a huge trigger for asthma . also people whose jobs expose them to things like asbestos , or other things they can inhale can be a trigger . i 'm just gon na start writing cause i ca n't draw fast enough . we have paint , remember that everybody has different triggers . people who have asthma do n't react the same way to the same things . and this one , i think , is really sad . some people can be triggered by food . you can be allergic to foods . or things in beer or wine , can trigger asthma in some people . now another trigger can be as common as stress . our body reacts to stress in a variety of ways . it can increase inflammation , which asthma is basically an inflammatory process . so this one i think is interesting . a common drug that most of us have probably taken , can be be a trigger in up to 30 percent of adults who take this drug , and that is aspirin . helps with your headaches , but sometimes causes your asthma to flare up . and lastly , babies who are completely different creatures from adults , they can have gi reflux , or what we call heartburn , where the things in their stomach go back up the esophagus . since they are so small , their system is so close together , it can go up the esophagus and into the trachea . so they can be triggered by gi reflux . as you can see , this reaches almost every aspect of life , this is probably why so many people have asthma , and it 's so different in everyone . so going back to our kind of clinical , medical way of thinking of asthma , if you are going to listen to a person breathe through your stethoscope , and this person has asthma , what might that sound like ? let me draw a stethoscope . are we gon na listen to these lungs ? now keep in mind , as i said earlier , there is fluid in here as well , so these smooth muscles constrict , but there 's also fluid and mucous getting secreted into these tubes as part of our body 's way of dealing with inflammation . so air and fluid together , what do they form ? they form air bubbles . so as these air bubbles pop and reform , and we 're trying to breathe through them , that 's why we would listen . we hear a high-pitched noise that 's referred to as wheezing . now wheezing is very characteristic of obstructive diseases , like asthma . wheezing basically sounds like a tiny little whistle , so when they inhale and then exhale , on the exhale you hear high-pitched noise all over the lung fields . now i 'm going to draw an imaginary line that divides our lung here . so the trachea , this is called the upper airway , and down here are the smaller airways . a wheezing in asthma is a small airway disease . it is a small airway disease that happens on the expiration , or when you breathe out . now if there 's noise on the inspiration , that 's usually caused by a foreign body , or some other kind of process that makes the upper airway constrict . that does n't really happen with asthma unless it 's super severe , and this person is just dying for breath . so usually asthma you can get an air in , and it 's on the expiration that we have a problem and you hear the wheezing . because again , the vacuum is sucking in air in the inspiration , so it 's going okay . but when you breathe out , passively , the restriction really causes a problem . so remember : asthma , wheezing , small airway disease . now this next part ... i do n't have asthma , so i always feel like i 'm not such a good judge on what it really feels like to have asthma . but we can imagine that if this person has trouble breathing out , breathing out is just as important as breathing in , if you ca n't do either it 's a very scary process . and this person coming in will be complaining of shortness of breath , so shortness-of-breath . sob is a very commonly used way to describe the symptom of ca n't catch your breath , panting , shortness of breath . now depending on how severe their attack is in the moment , a lot of people have rescue inhalers . when they 're panicking and ca n't breathe , this rescue inhaler can deliver some emergency drugs to open up that airway . and it 's such an important intervention for people who have asthma to not only breathe , but to feel like they can breathe , to help with the panic and just the discomfort of not being able to get a breath in and out . now lastly , i just want to mention that asthma , just from observation , seems to be related to two other diseases . there 's asthma , there 's eczema , which is a disease of the skin . you have excessively dry patches of skin that , again , flares up . it can be red-angry or dry and peely , a skin disease . and then the third , we have allergies , or some people call it allergic rhinitis , which is more proper for ( mumbling ) your nose , rhinitis . but most people are just calling it allergies . and these three things , for some reason seem to be good friends , in that a person who has one , is likely to have the other two . we do n't really do n't know why . we 're still studying why that relationship exists , but it does , especially in children . so this in a nutshell from a thousand miles above , is what asthma looks like , what it is . so just a few key words to remember . we have airway constriction , in the small airway that causes shortness of breath and sounds like wheezing on a stethoscope .
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sob is a very commonly used way to describe the symptom of ca n't catch your breath , panting , shortness of breath . now depending on how severe their attack is in the moment , a lot of people have rescue inhalers . when they 're panicking and ca n't breathe , this rescue inhaler can deliver some emergency drugs to open up that airway .
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can people die of asthma if they do n't have access to rescue inhalers ?
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when i first started thinking about this video , i realized that asthma is going to be hard to talk about because so many people have it , everybody knows at least a little bit about it , so it might be hard to get really to the bottom of what really is asthma . so , to do this , let 's go all the way back from the beginning . let 's just start by talking about the lungs , and what they look like and what they do . so , we have here your big trachea , and they branch off into your left and right bronchi . those are the two main stems of the lungs . and from there , they keep branching off like branches on a tree , and they get smaller and smaller . there are countless levels . i 'm gon na just try to draw a few levels here for us . so they keep branching off like this , you get the idea . when we inspire , or when we breathe in , inhaling , it 's kind of like a vacuum cleaner sucking air in . and these are all the tubes that are connected to it . so this is like the big hose . if you can imagine your vacuum breaks down into little hoses , that 's basically what it looks like . so in our lungs oxygen goes in , when we breathe in . o2 is oxygen , two oxygens . and then on the reverse side when we breathe out , we breathe out carbon dioxide , which is the symbol as co2 , one carbon and two oxygens . now asthma is classified as an obstructive disease where air is blocked on the way out , breathing out co2 . but we 'll get to that later exactly where that happens . for now if we are just looking at the set of tubes , otherwise known as our airway , and anywhere we go , if we take a cut like this across any of the tubes and we look at it up the tube , or we look at what is called a cross section of it , then it 's going to look something like this . so we have a round shape for the outside of the tube . and then we have an opening . and in the middle here we call it the lumen . the lumen is just the inside of any tube . this is where air actually goes through . and here in the walls of the airway , we have connective tissue , we have glands , we have all kinds of things . but i want to talk about this smooth muscle layer here that 's around in the wall of the airway . so since it 's a muscle , then it can have force and change the shape of things around it . so in asthma , what we care about is that the smooth muscles can actually constrict this airway . so to see what that looks like , let me draw this again here . again , if this is the outside of the wall , then a person who has active asthma happening at the moment , their airway 's going to be smaller , the lumen is going to be smaller , maybe about , let 's say this big . and what has happened , is that the smooth muscle around it is contracting hard and is clamping down on that lumen . to make matters even worse , when our body 's inflamed , it secretes fluid . so into the lumen , which is usually supposed to be open and dry , we have extra fluid . so when the opening is already smaller , it 's being flooded by mucous and fluid . and this whole picture together is what asthma looks like in our airways . now i just showed you one tube here , because we cut it once here . but imagine this process is happening in all these vacuum tubes , all these little levels . so the air is really having trouble moving . actually , if you could imagine a vacuum . let me just draw one here . this is the very primitive model of our vacuum . and if you could imagine that this machine has a lot of power sucking air in , but when it 's coming out , it 's a passive process , so there 's no power pushing the air out . so even though this constriction here will make it harder to suck air in , but at least it has a motor behind it , as opposed to when the air 's coming out , it just has to passively leave through the smaller straws . so that makes it harder on the exhale . we 'll come back to what that sounds like when we listen with the stethoscope . but first , let 's talk about what causes this process . why would your airway suddenly clamp down like that ? why would our body allow it , and what triggers it ? so i promise that every time i talk about lungs , the first thing i will always say is , smoking . smoking can be a huge trigger for asthma . does n't even have to be firsthand smoke , it can be secondhand . in fact , kids who have asthma , they 're exposed to parents who smoke in the house . even parents who are smoking outside , but then wear the same clothes inside the house . that can trigger asthma , because these smoke particles are billions and billions of little things that do n't belong in the lungs , and when they 're in there , this process can happen . also because we live in a time where there 's so much machinery around us , this is a car if you can tell ... so car exhaust and pollution in general in the cities can be a huge trigger for asthma . also people whose jobs expose them to things like asbestos , or other things they can inhale can be a trigger . i 'm just gon na start writing cause i ca n't draw fast enough . we have paint , remember that everybody has different triggers . people who have asthma do n't react the same way to the same things . and this one , i think , is really sad . some people can be triggered by food . you can be allergic to foods . or things in beer or wine , can trigger asthma in some people . now another trigger can be as common as stress . our body reacts to stress in a variety of ways . it can increase inflammation , which asthma is basically an inflammatory process . so this one i think is interesting . a common drug that most of us have probably taken , can be be a trigger in up to 30 percent of adults who take this drug , and that is aspirin . helps with your headaches , but sometimes causes your asthma to flare up . and lastly , babies who are completely different creatures from adults , they can have gi reflux , or what we call heartburn , where the things in their stomach go back up the esophagus . since they are so small , their system is so close together , it can go up the esophagus and into the trachea . so they can be triggered by gi reflux . as you can see , this reaches almost every aspect of life , this is probably why so many people have asthma , and it 's so different in everyone . so going back to our kind of clinical , medical way of thinking of asthma , if you are going to listen to a person breathe through your stethoscope , and this person has asthma , what might that sound like ? let me draw a stethoscope . are we gon na listen to these lungs ? now keep in mind , as i said earlier , there is fluid in here as well , so these smooth muscles constrict , but there 's also fluid and mucous getting secreted into these tubes as part of our body 's way of dealing with inflammation . so air and fluid together , what do they form ? they form air bubbles . so as these air bubbles pop and reform , and we 're trying to breathe through them , that 's why we would listen . we hear a high-pitched noise that 's referred to as wheezing . now wheezing is very characteristic of obstructive diseases , like asthma . wheezing basically sounds like a tiny little whistle , so when they inhale and then exhale , on the exhale you hear high-pitched noise all over the lung fields . now i 'm going to draw an imaginary line that divides our lung here . so the trachea , this is called the upper airway , and down here are the smaller airways . a wheezing in asthma is a small airway disease . it is a small airway disease that happens on the expiration , or when you breathe out . now if there 's noise on the inspiration , that 's usually caused by a foreign body , or some other kind of process that makes the upper airway constrict . that does n't really happen with asthma unless it 's super severe , and this person is just dying for breath . so usually asthma you can get an air in , and it 's on the expiration that we have a problem and you hear the wheezing . because again , the vacuum is sucking in air in the inspiration , so it 's going okay . but when you breathe out , passively , the restriction really causes a problem . so remember : asthma , wheezing , small airway disease . now this next part ... i do n't have asthma , so i always feel like i 'm not such a good judge on what it really feels like to have asthma . but we can imagine that if this person has trouble breathing out , breathing out is just as important as breathing in , if you ca n't do either it 's a very scary process . and this person coming in will be complaining of shortness of breath , so shortness-of-breath . sob is a very commonly used way to describe the symptom of ca n't catch your breath , panting , shortness of breath . now depending on how severe their attack is in the moment , a lot of people have rescue inhalers . when they 're panicking and ca n't breathe , this rescue inhaler can deliver some emergency drugs to open up that airway . and it 's such an important intervention for people who have asthma to not only breathe , but to feel like they can breathe , to help with the panic and just the discomfort of not being able to get a breath in and out . now lastly , i just want to mention that asthma , just from observation , seems to be related to two other diseases . there 's asthma , there 's eczema , which is a disease of the skin . you have excessively dry patches of skin that , again , flares up . it can be red-angry or dry and peely , a skin disease . and then the third , we have allergies , or some people call it allergic rhinitis , which is more proper for ( mumbling ) your nose , rhinitis . but most people are just calling it allergies . and these three things , for some reason seem to be good friends , in that a person who has one , is likely to have the other two . we do n't really do n't know why . we 're still studying why that relationship exists , but it does , especially in children . so this in a nutshell from a thousand miles above , is what asthma looks like , what it is . so just a few key words to remember . we have airway constriction , in the small airway that causes shortness of breath and sounds like wheezing on a stethoscope .
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but when you breathe out , passively , the restriction really causes a problem . so remember : asthma , wheezing , small airway disease . now this next part ...
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can you get rid of asthma ?
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when i first started thinking about this video , i realized that asthma is going to be hard to talk about because so many people have it , everybody knows at least a little bit about it , so it might be hard to get really to the bottom of what really is asthma . so , to do this , let 's go all the way back from the beginning . let 's just start by talking about the lungs , and what they look like and what they do . so , we have here your big trachea , and they branch off into your left and right bronchi . those are the two main stems of the lungs . and from there , they keep branching off like branches on a tree , and they get smaller and smaller . there are countless levels . i 'm gon na just try to draw a few levels here for us . so they keep branching off like this , you get the idea . when we inspire , or when we breathe in , inhaling , it 's kind of like a vacuum cleaner sucking air in . and these are all the tubes that are connected to it . so this is like the big hose . if you can imagine your vacuum breaks down into little hoses , that 's basically what it looks like . so in our lungs oxygen goes in , when we breathe in . o2 is oxygen , two oxygens . and then on the reverse side when we breathe out , we breathe out carbon dioxide , which is the symbol as co2 , one carbon and two oxygens . now asthma is classified as an obstructive disease where air is blocked on the way out , breathing out co2 . but we 'll get to that later exactly where that happens . for now if we are just looking at the set of tubes , otherwise known as our airway , and anywhere we go , if we take a cut like this across any of the tubes and we look at it up the tube , or we look at what is called a cross section of it , then it 's going to look something like this . so we have a round shape for the outside of the tube . and then we have an opening . and in the middle here we call it the lumen . the lumen is just the inside of any tube . this is where air actually goes through . and here in the walls of the airway , we have connective tissue , we have glands , we have all kinds of things . but i want to talk about this smooth muscle layer here that 's around in the wall of the airway . so since it 's a muscle , then it can have force and change the shape of things around it . so in asthma , what we care about is that the smooth muscles can actually constrict this airway . so to see what that looks like , let me draw this again here . again , if this is the outside of the wall , then a person who has active asthma happening at the moment , their airway 's going to be smaller , the lumen is going to be smaller , maybe about , let 's say this big . and what has happened , is that the smooth muscle around it is contracting hard and is clamping down on that lumen . to make matters even worse , when our body 's inflamed , it secretes fluid . so into the lumen , which is usually supposed to be open and dry , we have extra fluid . so when the opening is already smaller , it 's being flooded by mucous and fluid . and this whole picture together is what asthma looks like in our airways . now i just showed you one tube here , because we cut it once here . but imagine this process is happening in all these vacuum tubes , all these little levels . so the air is really having trouble moving . actually , if you could imagine a vacuum . let me just draw one here . this is the very primitive model of our vacuum . and if you could imagine that this machine has a lot of power sucking air in , but when it 's coming out , it 's a passive process , so there 's no power pushing the air out . so even though this constriction here will make it harder to suck air in , but at least it has a motor behind it , as opposed to when the air 's coming out , it just has to passively leave through the smaller straws . so that makes it harder on the exhale . we 'll come back to what that sounds like when we listen with the stethoscope . but first , let 's talk about what causes this process . why would your airway suddenly clamp down like that ? why would our body allow it , and what triggers it ? so i promise that every time i talk about lungs , the first thing i will always say is , smoking . smoking can be a huge trigger for asthma . does n't even have to be firsthand smoke , it can be secondhand . in fact , kids who have asthma , they 're exposed to parents who smoke in the house . even parents who are smoking outside , but then wear the same clothes inside the house . that can trigger asthma , because these smoke particles are billions and billions of little things that do n't belong in the lungs , and when they 're in there , this process can happen . also because we live in a time where there 's so much machinery around us , this is a car if you can tell ... so car exhaust and pollution in general in the cities can be a huge trigger for asthma . also people whose jobs expose them to things like asbestos , or other things they can inhale can be a trigger . i 'm just gon na start writing cause i ca n't draw fast enough . we have paint , remember that everybody has different triggers . people who have asthma do n't react the same way to the same things . and this one , i think , is really sad . some people can be triggered by food . you can be allergic to foods . or things in beer or wine , can trigger asthma in some people . now another trigger can be as common as stress . our body reacts to stress in a variety of ways . it can increase inflammation , which asthma is basically an inflammatory process . so this one i think is interesting . a common drug that most of us have probably taken , can be be a trigger in up to 30 percent of adults who take this drug , and that is aspirin . helps with your headaches , but sometimes causes your asthma to flare up . and lastly , babies who are completely different creatures from adults , they can have gi reflux , or what we call heartburn , where the things in their stomach go back up the esophagus . since they are so small , their system is so close together , it can go up the esophagus and into the trachea . so they can be triggered by gi reflux . as you can see , this reaches almost every aspect of life , this is probably why so many people have asthma , and it 's so different in everyone . so going back to our kind of clinical , medical way of thinking of asthma , if you are going to listen to a person breathe through your stethoscope , and this person has asthma , what might that sound like ? let me draw a stethoscope . are we gon na listen to these lungs ? now keep in mind , as i said earlier , there is fluid in here as well , so these smooth muscles constrict , but there 's also fluid and mucous getting secreted into these tubes as part of our body 's way of dealing with inflammation . so air and fluid together , what do they form ? they form air bubbles . so as these air bubbles pop and reform , and we 're trying to breathe through them , that 's why we would listen . we hear a high-pitched noise that 's referred to as wheezing . now wheezing is very characteristic of obstructive diseases , like asthma . wheezing basically sounds like a tiny little whistle , so when they inhale and then exhale , on the exhale you hear high-pitched noise all over the lung fields . now i 'm going to draw an imaginary line that divides our lung here . so the trachea , this is called the upper airway , and down here are the smaller airways . a wheezing in asthma is a small airway disease . it is a small airway disease that happens on the expiration , or when you breathe out . now if there 's noise on the inspiration , that 's usually caused by a foreign body , or some other kind of process that makes the upper airway constrict . that does n't really happen with asthma unless it 's super severe , and this person is just dying for breath . so usually asthma you can get an air in , and it 's on the expiration that we have a problem and you hear the wheezing . because again , the vacuum is sucking in air in the inspiration , so it 's going okay . but when you breathe out , passively , the restriction really causes a problem . so remember : asthma , wheezing , small airway disease . now this next part ... i do n't have asthma , so i always feel like i 'm not such a good judge on what it really feels like to have asthma . but we can imagine that if this person has trouble breathing out , breathing out is just as important as breathing in , if you ca n't do either it 's a very scary process . and this person coming in will be complaining of shortness of breath , so shortness-of-breath . sob is a very commonly used way to describe the symptom of ca n't catch your breath , panting , shortness of breath . now depending on how severe their attack is in the moment , a lot of people have rescue inhalers . when they 're panicking and ca n't breathe , this rescue inhaler can deliver some emergency drugs to open up that airway . and it 's such an important intervention for people who have asthma to not only breathe , but to feel like they can breathe , to help with the panic and just the discomfort of not being able to get a breath in and out . now lastly , i just want to mention that asthma , just from observation , seems to be related to two other diseases . there 's asthma , there 's eczema , which is a disease of the skin . you have excessively dry patches of skin that , again , flares up . it can be red-angry or dry and peely , a skin disease . and then the third , we have allergies , or some people call it allergic rhinitis , which is more proper for ( mumbling ) your nose , rhinitis . but most people are just calling it allergies . and these three things , for some reason seem to be good friends , in that a person who has one , is likely to have the other two . we do n't really do n't know why . we 're still studying why that relationship exists , but it does , especially in children . so this in a nutshell from a thousand miles above , is what asthma looks like , what it is . so just a few key words to remember . we have airway constriction , in the small airway that causes shortness of breath and sounds like wheezing on a stethoscope .
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but when you breathe out , passively , the restriction really causes a problem . so remember : asthma , wheezing , small airway disease . now this next part ...
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and how do you know if you have asthma ?
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when i first started thinking about this video , i realized that asthma is going to be hard to talk about because so many people have it , everybody knows at least a little bit about it , so it might be hard to get really to the bottom of what really is asthma . so , to do this , let 's go all the way back from the beginning . let 's just start by talking about the lungs , and what they look like and what they do . so , we have here your big trachea , and they branch off into your left and right bronchi . those are the two main stems of the lungs . and from there , they keep branching off like branches on a tree , and they get smaller and smaller . there are countless levels . i 'm gon na just try to draw a few levels here for us . so they keep branching off like this , you get the idea . when we inspire , or when we breathe in , inhaling , it 's kind of like a vacuum cleaner sucking air in . and these are all the tubes that are connected to it . so this is like the big hose . if you can imagine your vacuum breaks down into little hoses , that 's basically what it looks like . so in our lungs oxygen goes in , when we breathe in . o2 is oxygen , two oxygens . and then on the reverse side when we breathe out , we breathe out carbon dioxide , which is the symbol as co2 , one carbon and two oxygens . now asthma is classified as an obstructive disease where air is blocked on the way out , breathing out co2 . but we 'll get to that later exactly where that happens . for now if we are just looking at the set of tubes , otherwise known as our airway , and anywhere we go , if we take a cut like this across any of the tubes and we look at it up the tube , or we look at what is called a cross section of it , then it 's going to look something like this . so we have a round shape for the outside of the tube . and then we have an opening . and in the middle here we call it the lumen . the lumen is just the inside of any tube . this is where air actually goes through . and here in the walls of the airway , we have connective tissue , we have glands , we have all kinds of things . but i want to talk about this smooth muscle layer here that 's around in the wall of the airway . so since it 's a muscle , then it can have force and change the shape of things around it . so in asthma , what we care about is that the smooth muscles can actually constrict this airway . so to see what that looks like , let me draw this again here . again , if this is the outside of the wall , then a person who has active asthma happening at the moment , their airway 's going to be smaller , the lumen is going to be smaller , maybe about , let 's say this big . and what has happened , is that the smooth muscle around it is contracting hard and is clamping down on that lumen . to make matters even worse , when our body 's inflamed , it secretes fluid . so into the lumen , which is usually supposed to be open and dry , we have extra fluid . so when the opening is already smaller , it 's being flooded by mucous and fluid . and this whole picture together is what asthma looks like in our airways . now i just showed you one tube here , because we cut it once here . but imagine this process is happening in all these vacuum tubes , all these little levels . so the air is really having trouble moving . actually , if you could imagine a vacuum . let me just draw one here . this is the very primitive model of our vacuum . and if you could imagine that this machine has a lot of power sucking air in , but when it 's coming out , it 's a passive process , so there 's no power pushing the air out . so even though this constriction here will make it harder to suck air in , but at least it has a motor behind it , as opposed to when the air 's coming out , it just has to passively leave through the smaller straws . so that makes it harder on the exhale . we 'll come back to what that sounds like when we listen with the stethoscope . but first , let 's talk about what causes this process . why would your airway suddenly clamp down like that ? why would our body allow it , and what triggers it ? so i promise that every time i talk about lungs , the first thing i will always say is , smoking . smoking can be a huge trigger for asthma . does n't even have to be firsthand smoke , it can be secondhand . in fact , kids who have asthma , they 're exposed to parents who smoke in the house . even parents who are smoking outside , but then wear the same clothes inside the house . that can trigger asthma , because these smoke particles are billions and billions of little things that do n't belong in the lungs , and when they 're in there , this process can happen . also because we live in a time where there 's so much machinery around us , this is a car if you can tell ... so car exhaust and pollution in general in the cities can be a huge trigger for asthma . also people whose jobs expose them to things like asbestos , or other things they can inhale can be a trigger . i 'm just gon na start writing cause i ca n't draw fast enough . we have paint , remember that everybody has different triggers . people who have asthma do n't react the same way to the same things . and this one , i think , is really sad . some people can be triggered by food . you can be allergic to foods . or things in beer or wine , can trigger asthma in some people . now another trigger can be as common as stress . our body reacts to stress in a variety of ways . it can increase inflammation , which asthma is basically an inflammatory process . so this one i think is interesting . a common drug that most of us have probably taken , can be be a trigger in up to 30 percent of adults who take this drug , and that is aspirin . helps with your headaches , but sometimes causes your asthma to flare up . and lastly , babies who are completely different creatures from adults , they can have gi reflux , or what we call heartburn , where the things in their stomach go back up the esophagus . since they are so small , their system is so close together , it can go up the esophagus and into the trachea . so they can be triggered by gi reflux . as you can see , this reaches almost every aspect of life , this is probably why so many people have asthma , and it 's so different in everyone . so going back to our kind of clinical , medical way of thinking of asthma , if you are going to listen to a person breathe through your stethoscope , and this person has asthma , what might that sound like ? let me draw a stethoscope . are we gon na listen to these lungs ? now keep in mind , as i said earlier , there is fluid in here as well , so these smooth muscles constrict , but there 's also fluid and mucous getting secreted into these tubes as part of our body 's way of dealing with inflammation . so air and fluid together , what do they form ? they form air bubbles . so as these air bubbles pop and reform , and we 're trying to breathe through them , that 's why we would listen . we hear a high-pitched noise that 's referred to as wheezing . now wheezing is very characteristic of obstructive diseases , like asthma . wheezing basically sounds like a tiny little whistle , so when they inhale and then exhale , on the exhale you hear high-pitched noise all over the lung fields . now i 'm going to draw an imaginary line that divides our lung here . so the trachea , this is called the upper airway , and down here are the smaller airways . a wheezing in asthma is a small airway disease . it is a small airway disease that happens on the expiration , or when you breathe out . now if there 's noise on the inspiration , that 's usually caused by a foreign body , or some other kind of process that makes the upper airway constrict . that does n't really happen with asthma unless it 's super severe , and this person is just dying for breath . so usually asthma you can get an air in , and it 's on the expiration that we have a problem and you hear the wheezing . because again , the vacuum is sucking in air in the inspiration , so it 's going okay . but when you breathe out , passively , the restriction really causes a problem . so remember : asthma , wheezing , small airway disease . now this next part ... i do n't have asthma , so i always feel like i 'm not such a good judge on what it really feels like to have asthma . but we can imagine that if this person has trouble breathing out , breathing out is just as important as breathing in , if you ca n't do either it 's a very scary process . and this person coming in will be complaining of shortness of breath , so shortness-of-breath . sob is a very commonly used way to describe the symptom of ca n't catch your breath , panting , shortness of breath . now depending on how severe their attack is in the moment , a lot of people have rescue inhalers . when they 're panicking and ca n't breathe , this rescue inhaler can deliver some emergency drugs to open up that airway . and it 's such an important intervention for people who have asthma to not only breathe , but to feel like they can breathe , to help with the panic and just the discomfort of not being able to get a breath in and out . now lastly , i just want to mention that asthma , just from observation , seems to be related to two other diseases . there 's asthma , there 's eczema , which is a disease of the skin . you have excessively dry patches of skin that , again , flares up . it can be red-angry or dry and peely , a skin disease . and then the third , we have allergies , or some people call it allergic rhinitis , which is more proper for ( mumbling ) your nose , rhinitis . but most people are just calling it allergies . and these three things , for some reason seem to be good friends , in that a person who has one , is likely to have the other two . we do n't really do n't know why . we 're still studying why that relationship exists , but it does , especially in children . so this in a nutshell from a thousand miles above , is what asthma looks like , what it is . so just a few key words to remember . we have airway constriction , in the small airway that causes shortness of breath and sounds like wheezing on a stethoscope .
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now this next part ... i do n't have asthma , so i always feel like i 'm not such a good judge on what it really feels like to have asthma . but we can imagine that if this person has trouble breathing out , breathing out is just as important as breathing in , if you ca n't do either it 's a very scary process .
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can you get asthma after you are born like when you are ten or eight ?
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when i first started thinking about this video , i realized that asthma is going to be hard to talk about because so many people have it , everybody knows at least a little bit about it , so it might be hard to get really to the bottom of what really is asthma . so , to do this , let 's go all the way back from the beginning . let 's just start by talking about the lungs , and what they look like and what they do . so , we have here your big trachea , and they branch off into your left and right bronchi . those are the two main stems of the lungs . and from there , they keep branching off like branches on a tree , and they get smaller and smaller . there are countless levels . i 'm gon na just try to draw a few levels here for us . so they keep branching off like this , you get the idea . when we inspire , or when we breathe in , inhaling , it 's kind of like a vacuum cleaner sucking air in . and these are all the tubes that are connected to it . so this is like the big hose . if you can imagine your vacuum breaks down into little hoses , that 's basically what it looks like . so in our lungs oxygen goes in , when we breathe in . o2 is oxygen , two oxygens . and then on the reverse side when we breathe out , we breathe out carbon dioxide , which is the symbol as co2 , one carbon and two oxygens . now asthma is classified as an obstructive disease where air is blocked on the way out , breathing out co2 . but we 'll get to that later exactly where that happens . for now if we are just looking at the set of tubes , otherwise known as our airway , and anywhere we go , if we take a cut like this across any of the tubes and we look at it up the tube , or we look at what is called a cross section of it , then it 's going to look something like this . so we have a round shape for the outside of the tube . and then we have an opening . and in the middle here we call it the lumen . the lumen is just the inside of any tube . this is where air actually goes through . and here in the walls of the airway , we have connective tissue , we have glands , we have all kinds of things . but i want to talk about this smooth muscle layer here that 's around in the wall of the airway . so since it 's a muscle , then it can have force and change the shape of things around it . so in asthma , what we care about is that the smooth muscles can actually constrict this airway . so to see what that looks like , let me draw this again here . again , if this is the outside of the wall , then a person who has active asthma happening at the moment , their airway 's going to be smaller , the lumen is going to be smaller , maybe about , let 's say this big . and what has happened , is that the smooth muscle around it is contracting hard and is clamping down on that lumen . to make matters even worse , when our body 's inflamed , it secretes fluid . so into the lumen , which is usually supposed to be open and dry , we have extra fluid . so when the opening is already smaller , it 's being flooded by mucous and fluid . and this whole picture together is what asthma looks like in our airways . now i just showed you one tube here , because we cut it once here . but imagine this process is happening in all these vacuum tubes , all these little levels . so the air is really having trouble moving . actually , if you could imagine a vacuum . let me just draw one here . this is the very primitive model of our vacuum . and if you could imagine that this machine has a lot of power sucking air in , but when it 's coming out , it 's a passive process , so there 's no power pushing the air out . so even though this constriction here will make it harder to suck air in , but at least it has a motor behind it , as opposed to when the air 's coming out , it just has to passively leave through the smaller straws . so that makes it harder on the exhale . we 'll come back to what that sounds like when we listen with the stethoscope . but first , let 's talk about what causes this process . why would your airway suddenly clamp down like that ? why would our body allow it , and what triggers it ? so i promise that every time i talk about lungs , the first thing i will always say is , smoking . smoking can be a huge trigger for asthma . does n't even have to be firsthand smoke , it can be secondhand . in fact , kids who have asthma , they 're exposed to parents who smoke in the house . even parents who are smoking outside , but then wear the same clothes inside the house . that can trigger asthma , because these smoke particles are billions and billions of little things that do n't belong in the lungs , and when they 're in there , this process can happen . also because we live in a time where there 's so much machinery around us , this is a car if you can tell ... so car exhaust and pollution in general in the cities can be a huge trigger for asthma . also people whose jobs expose them to things like asbestos , or other things they can inhale can be a trigger . i 'm just gon na start writing cause i ca n't draw fast enough . we have paint , remember that everybody has different triggers . people who have asthma do n't react the same way to the same things . and this one , i think , is really sad . some people can be triggered by food . you can be allergic to foods . or things in beer or wine , can trigger asthma in some people . now another trigger can be as common as stress . our body reacts to stress in a variety of ways . it can increase inflammation , which asthma is basically an inflammatory process . so this one i think is interesting . a common drug that most of us have probably taken , can be be a trigger in up to 30 percent of adults who take this drug , and that is aspirin . helps with your headaches , but sometimes causes your asthma to flare up . and lastly , babies who are completely different creatures from adults , they can have gi reflux , or what we call heartburn , where the things in their stomach go back up the esophagus . since they are so small , their system is so close together , it can go up the esophagus and into the trachea . so they can be triggered by gi reflux . as you can see , this reaches almost every aspect of life , this is probably why so many people have asthma , and it 's so different in everyone . so going back to our kind of clinical , medical way of thinking of asthma , if you are going to listen to a person breathe through your stethoscope , and this person has asthma , what might that sound like ? let me draw a stethoscope . are we gon na listen to these lungs ? now keep in mind , as i said earlier , there is fluid in here as well , so these smooth muscles constrict , but there 's also fluid and mucous getting secreted into these tubes as part of our body 's way of dealing with inflammation . so air and fluid together , what do they form ? they form air bubbles . so as these air bubbles pop and reform , and we 're trying to breathe through them , that 's why we would listen . we hear a high-pitched noise that 's referred to as wheezing . now wheezing is very characteristic of obstructive diseases , like asthma . wheezing basically sounds like a tiny little whistle , so when they inhale and then exhale , on the exhale you hear high-pitched noise all over the lung fields . now i 'm going to draw an imaginary line that divides our lung here . so the trachea , this is called the upper airway , and down here are the smaller airways . a wheezing in asthma is a small airway disease . it is a small airway disease that happens on the expiration , or when you breathe out . now if there 's noise on the inspiration , that 's usually caused by a foreign body , or some other kind of process that makes the upper airway constrict . that does n't really happen with asthma unless it 's super severe , and this person is just dying for breath . so usually asthma you can get an air in , and it 's on the expiration that we have a problem and you hear the wheezing . because again , the vacuum is sucking in air in the inspiration , so it 's going okay . but when you breathe out , passively , the restriction really causes a problem . so remember : asthma , wheezing , small airway disease . now this next part ... i do n't have asthma , so i always feel like i 'm not such a good judge on what it really feels like to have asthma . but we can imagine that if this person has trouble breathing out , breathing out is just as important as breathing in , if you ca n't do either it 's a very scary process . and this person coming in will be complaining of shortness of breath , so shortness-of-breath . sob is a very commonly used way to describe the symptom of ca n't catch your breath , panting , shortness of breath . now depending on how severe their attack is in the moment , a lot of people have rescue inhalers . when they 're panicking and ca n't breathe , this rescue inhaler can deliver some emergency drugs to open up that airway . and it 's such an important intervention for people who have asthma to not only breathe , but to feel like they can breathe , to help with the panic and just the discomfort of not being able to get a breath in and out . now lastly , i just want to mention that asthma , just from observation , seems to be related to two other diseases . there 's asthma , there 's eczema , which is a disease of the skin . you have excessively dry patches of skin that , again , flares up . it can be red-angry or dry and peely , a skin disease . and then the third , we have allergies , or some people call it allergic rhinitis , which is more proper for ( mumbling ) your nose , rhinitis . but most people are just calling it allergies . and these three things , for some reason seem to be good friends , in that a person who has one , is likely to have the other two . we do n't really do n't know why . we 're still studying why that relationship exists , but it does , especially in children . so this in a nutshell from a thousand miles above , is what asthma looks like , what it is . so just a few key words to remember . we have airway constriction , in the small airway that causes shortness of breath and sounds like wheezing on a stethoscope .
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sob is a very commonly used way to describe the symptom of ca n't catch your breath , panting , shortness of breath . now depending on how severe their attack is in the moment , a lot of people have rescue inhalers . when they 're panicking and ca n't breathe , this rescue inhaler can deliver some emergency drugs to open up that airway .
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what kind of drugs do inhalers give ?
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when i first started thinking about this video , i realized that asthma is going to be hard to talk about because so many people have it , everybody knows at least a little bit about it , so it might be hard to get really to the bottom of what really is asthma . so , to do this , let 's go all the way back from the beginning . let 's just start by talking about the lungs , and what they look like and what they do . so , we have here your big trachea , and they branch off into your left and right bronchi . those are the two main stems of the lungs . and from there , they keep branching off like branches on a tree , and they get smaller and smaller . there are countless levels . i 'm gon na just try to draw a few levels here for us . so they keep branching off like this , you get the idea . when we inspire , or when we breathe in , inhaling , it 's kind of like a vacuum cleaner sucking air in . and these are all the tubes that are connected to it . so this is like the big hose . if you can imagine your vacuum breaks down into little hoses , that 's basically what it looks like . so in our lungs oxygen goes in , when we breathe in . o2 is oxygen , two oxygens . and then on the reverse side when we breathe out , we breathe out carbon dioxide , which is the symbol as co2 , one carbon and two oxygens . now asthma is classified as an obstructive disease where air is blocked on the way out , breathing out co2 . but we 'll get to that later exactly where that happens . for now if we are just looking at the set of tubes , otherwise known as our airway , and anywhere we go , if we take a cut like this across any of the tubes and we look at it up the tube , or we look at what is called a cross section of it , then it 's going to look something like this . so we have a round shape for the outside of the tube . and then we have an opening . and in the middle here we call it the lumen . the lumen is just the inside of any tube . this is where air actually goes through . and here in the walls of the airway , we have connective tissue , we have glands , we have all kinds of things . but i want to talk about this smooth muscle layer here that 's around in the wall of the airway . so since it 's a muscle , then it can have force and change the shape of things around it . so in asthma , what we care about is that the smooth muscles can actually constrict this airway . so to see what that looks like , let me draw this again here . again , if this is the outside of the wall , then a person who has active asthma happening at the moment , their airway 's going to be smaller , the lumen is going to be smaller , maybe about , let 's say this big . and what has happened , is that the smooth muscle around it is contracting hard and is clamping down on that lumen . to make matters even worse , when our body 's inflamed , it secretes fluid . so into the lumen , which is usually supposed to be open and dry , we have extra fluid . so when the opening is already smaller , it 's being flooded by mucous and fluid . and this whole picture together is what asthma looks like in our airways . now i just showed you one tube here , because we cut it once here . but imagine this process is happening in all these vacuum tubes , all these little levels . so the air is really having trouble moving . actually , if you could imagine a vacuum . let me just draw one here . this is the very primitive model of our vacuum . and if you could imagine that this machine has a lot of power sucking air in , but when it 's coming out , it 's a passive process , so there 's no power pushing the air out . so even though this constriction here will make it harder to suck air in , but at least it has a motor behind it , as opposed to when the air 's coming out , it just has to passively leave through the smaller straws . so that makes it harder on the exhale . we 'll come back to what that sounds like when we listen with the stethoscope . but first , let 's talk about what causes this process . why would your airway suddenly clamp down like that ? why would our body allow it , and what triggers it ? so i promise that every time i talk about lungs , the first thing i will always say is , smoking . smoking can be a huge trigger for asthma . does n't even have to be firsthand smoke , it can be secondhand . in fact , kids who have asthma , they 're exposed to parents who smoke in the house . even parents who are smoking outside , but then wear the same clothes inside the house . that can trigger asthma , because these smoke particles are billions and billions of little things that do n't belong in the lungs , and when they 're in there , this process can happen . also because we live in a time where there 's so much machinery around us , this is a car if you can tell ... so car exhaust and pollution in general in the cities can be a huge trigger for asthma . also people whose jobs expose them to things like asbestos , or other things they can inhale can be a trigger . i 'm just gon na start writing cause i ca n't draw fast enough . we have paint , remember that everybody has different triggers . people who have asthma do n't react the same way to the same things . and this one , i think , is really sad . some people can be triggered by food . you can be allergic to foods . or things in beer or wine , can trigger asthma in some people . now another trigger can be as common as stress . our body reacts to stress in a variety of ways . it can increase inflammation , which asthma is basically an inflammatory process . so this one i think is interesting . a common drug that most of us have probably taken , can be be a trigger in up to 30 percent of adults who take this drug , and that is aspirin . helps with your headaches , but sometimes causes your asthma to flare up . and lastly , babies who are completely different creatures from adults , they can have gi reflux , or what we call heartburn , where the things in their stomach go back up the esophagus . since they are so small , their system is so close together , it can go up the esophagus and into the trachea . so they can be triggered by gi reflux . as you can see , this reaches almost every aspect of life , this is probably why so many people have asthma , and it 's so different in everyone . so going back to our kind of clinical , medical way of thinking of asthma , if you are going to listen to a person breathe through your stethoscope , and this person has asthma , what might that sound like ? let me draw a stethoscope . are we gon na listen to these lungs ? now keep in mind , as i said earlier , there is fluid in here as well , so these smooth muscles constrict , but there 's also fluid and mucous getting secreted into these tubes as part of our body 's way of dealing with inflammation . so air and fluid together , what do they form ? they form air bubbles . so as these air bubbles pop and reform , and we 're trying to breathe through them , that 's why we would listen . we hear a high-pitched noise that 's referred to as wheezing . now wheezing is very characteristic of obstructive diseases , like asthma . wheezing basically sounds like a tiny little whistle , so when they inhale and then exhale , on the exhale you hear high-pitched noise all over the lung fields . now i 'm going to draw an imaginary line that divides our lung here . so the trachea , this is called the upper airway , and down here are the smaller airways . a wheezing in asthma is a small airway disease . it is a small airway disease that happens on the expiration , or when you breathe out . now if there 's noise on the inspiration , that 's usually caused by a foreign body , or some other kind of process that makes the upper airway constrict . that does n't really happen with asthma unless it 's super severe , and this person is just dying for breath . so usually asthma you can get an air in , and it 's on the expiration that we have a problem and you hear the wheezing . because again , the vacuum is sucking in air in the inspiration , so it 's going okay . but when you breathe out , passively , the restriction really causes a problem . so remember : asthma , wheezing , small airway disease . now this next part ... i do n't have asthma , so i always feel like i 'm not such a good judge on what it really feels like to have asthma . but we can imagine that if this person has trouble breathing out , breathing out is just as important as breathing in , if you ca n't do either it 's a very scary process . and this person coming in will be complaining of shortness of breath , so shortness-of-breath . sob is a very commonly used way to describe the symptom of ca n't catch your breath , panting , shortness of breath . now depending on how severe their attack is in the moment , a lot of people have rescue inhalers . when they 're panicking and ca n't breathe , this rescue inhaler can deliver some emergency drugs to open up that airway . and it 's such an important intervention for people who have asthma to not only breathe , but to feel like they can breathe , to help with the panic and just the discomfort of not being able to get a breath in and out . now lastly , i just want to mention that asthma , just from observation , seems to be related to two other diseases . there 's asthma , there 's eczema , which is a disease of the skin . you have excessively dry patches of skin that , again , flares up . it can be red-angry or dry and peely , a skin disease . and then the third , we have allergies , or some people call it allergic rhinitis , which is more proper for ( mumbling ) your nose , rhinitis . but most people are just calling it allergies . and these three things , for some reason seem to be good friends , in that a person who has one , is likely to have the other two . we do n't really do n't know why . we 're still studying why that relationship exists , but it does , especially in children . so this in a nutshell from a thousand miles above , is what asthma looks like , what it is . so just a few key words to remember . we have airway constriction , in the small airway that causes shortness of breath and sounds like wheezing on a stethoscope .
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but when you breathe out , passively , the restriction really causes a problem . so remember : asthma , wheezing , small airway disease . now this next part ...
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what is the most common age to devolve asthma ?
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when i first started thinking about this video , i realized that asthma is going to be hard to talk about because so many people have it , everybody knows at least a little bit about it , so it might be hard to get really to the bottom of what really is asthma . so , to do this , let 's go all the way back from the beginning . let 's just start by talking about the lungs , and what they look like and what they do . so , we have here your big trachea , and they branch off into your left and right bronchi . those are the two main stems of the lungs . and from there , they keep branching off like branches on a tree , and they get smaller and smaller . there are countless levels . i 'm gon na just try to draw a few levels here for us . so they keep branching off like this , you get the idea . when we inspire , or when we breathe in , inhaling , it 's kind of like a vacuum cleaner sucking air in . and these are all the tubes that are connected to it . so this is like the big hose . if you can imagine your vacuum breaks down into little hoses , that 's basically what it looks like . so in our lungs oxygen goes in , when we breathe in . o2 is oxygen , two oxygens . and then on the reverse side when we breathe out , we breathe out carbon dioxide , which is the symbol as co2 , one carbon and two oxygens . now asthma is classified as an obstructive disease where air is blocked on the way out , breathing out co2 . but we 'll get to that later exactly where that happens . for now if we are just looking at the set of tubes , otherwise known as our airway , and anywhere we go , if we take a cut like this across any of the tubes and we look at it up the tube , or we look at what is called a cross section of it , then it 's going to look something like this . so we have a round shape for the outside of the tube . and then we have an opening . and in the middle here we call it the lumen . the lumen is just the inside of any tube . this is where air actually goes through . and here in the walls of the airway , we have connective tissue , we have glands , we have all kinds of things . but i want to talk about this smooth muscle layer here that 's around in the wall of the airway . so since it 's a muscle , then it can have force and change the shape of things around it . so in asthma , what we care about is that the smooth muscles can actually constrict this airway . so to see what that looks like , let me draw this again here . again , if this is the outside of the wall , then a person who has active asthma happening at the moment , their airway 's going to be smaller , the lumen is going to be smaller , maybe about , let 's say this big . and what has happened , is that the smooth muscle around it is contracting hard and is clamping down on that lumen . to make matters even worse , when our body 's inflamed , it secretes fluid . so into the lumen , which is usually supposed to be open and dry , we have extra fluid . so when the opening is already smaller , it 's being flooded by mucous and fluid . and this whole picture together is what asthma looks like in our airways . now i just showed you one tube here , because we cut it once here . but imagine this process is happening in all these vacuum tubes , all these little levels . so the air is really having trouble moving . actually , if you could imagine a vacuum . let me just draw one here . this is the very primitive model of our vacuum . and if you could imagine that this machine has a lot of power sucking air in , but when it 's coming out , it 's a passive process , so there 's no power pushing the air out . so even though this constriction here will make it harder to suck air in , but at least it has a motor behind it , as opposed to when the air 's coming out , it just has to passively leave through the smaller straws . so that makes it harder on the exhale . we 'll come back to what that sounds like when we listen with the stethoscope . but first , let 's talk about what causes this process . why would your airway suddenly clamp down like that ? why would our body allow it , and what triggers it ? so i promise that every time i talk about lungs , the first thing i will always say is , smoking . smoking can be a huge trigger for asthma . does n't even have to be firsthand smoke , it can be secondhand . in fact , kids who have asthma , they 're exposed to parents who smoke in the house . even parents who are smoking outside , but then wear the same clothes inside the house . that can trigger asthma , because these smoke particles are billions and billions of little things that do n't belong in the lungs , and when they 're in there , this process can happen . also because we live in a time where there 's so much machinery around us , this is a car if you can tell ... so car exhaust and pollution in general in the cities can be a huge trigger for asthma . also people whose jobs expose them to things like asbestos , or other things they can inhale can be a trigger . i 'm just gon na start writing cause i ca n't draw fast enough . we have paint , remember that everybody has different triggers . people who have asthma do n't react the same way to the same things . and this one , i think , is really sad . some people can be triggered by food . you can be allergic to foods . or things in beer or wine , can trigger asthma in some people . now another trigger can be as common as stress . our body reacts to stress in a variety of ways . it can increase inflammation , which asthma is basically an inflammatory process . so this one i think is interesting . a common drug that most of us have probably taken , can be be a trigger in up to 30 percent of adults who take this drug , and that is aspirin . helps with your headaches , but sometimes causes your asthma to flare up . and lastly , babies who are completely different creatures from adults , they can have gi reflux , or what we call heartburn , where the things in their stomach go back up the esophagus . since they are so small , their system is so close together , it can go up the esophagus and into the trachea . so they can be triggered by gi reflux . as you can see , this reaches almost every aspect of life , this is probably why so many people have asthma , and it 's so different in everyone . so going back to our kind of clinical , medical way of thinking of asthma , if you are going to listen to a person breathe through your stethoscope , and this person has asthma , what might that sound like ? let me draw a stethoscope . are we gon na listen to these lungs ? now keep in mind , as i said earlier , there is fluid in here as well , so these smooth muscles constrict , but there 's also fluid and mucous getting secreted into these tubes as part of our body 's way of dealing with inflammation . so air and fluid together , what do they form ? they form air bubbles . so as these air bubbles pop and reform , and we 're trying to breathe through them , that 's why we would listen . we hear a high-pitched noise that 's referred to as wheezing . now wheezing is very characteristic of obstructive diseases , like asthma . wheezing basically sounds like a tiny little whistle , so when they inhale and then exhale , on the exhale you hear high-pitched noise all over the lung fields . now i 'm going to draw an imaginary line that divides our lung here . so the trachea , this is called the upper airway , and down here are the smaller airways . a wheezing in asthma is a small airway disease . it is a small airway disease that happens on the expiration , or when you breathe out . now if there 's noise on the inspiration , that 's usually caused by a foreign body , or some other kind of process that makes the upper airway constrict . that does n't really happen with asthma unless it 's super severe , and this person is just dying for breath . so usually asthma you can get an air in , and it 's on the expiration that we have a problem and you hear the wheezing . because again , the vacuum is sucking in air in the inspiration , so it 's going okay . but when you breathe out , passively , the restriction really causes a problem . so remember : asthma , wheezing , small airway disease . now this next part ... i do n't have asthma , so i always feel like i 'm not such a good judge on what it really feels like to have asthma . but we can imagine that if this person has trouble breathing out , breathing out is just as important as breathing in , if you ca n't do either it 's a very scary process . and this person coming in will be complaining of shortness of breath , so shortness-of-breath . sob is a very commonly used way to describe the symptom of ca n't catch your breath , panting , shortness of breath . now depending on how severe their attack is in the moment , a lot of people have rescue inhalers . when they 're panicking and ca n't breathe , this rescue inhaler can deliver some emergency drugs to open up that airway . and it 's such an important intervention for people who have asthma to not only breathe , but to feel like they can breathe , to help with the panic and just the discomfort of not being able to get a breath in and out . now lastly , i just want to mention that asthma , just from observation , seems to be related to two other diseases . there 's asthma , there 's eczema , which is a disease of the skin . you have excessively dry patches of skin that , again , flares up . it can be red-angry or dry and peely , a skin disease . and then the third , we have allergies , or some people call it allergic rhinitis , which is more proper for ( mumbling ) your nose , rhinitis . but most people are just calling it allergies . and these three things , for some reason seem to be good friends , in that a person who has one , is likely to have the other two . we do n't really do n't know why . we 're still studying why that relationship exists , but it does , especially in children . so this in a nutshell from a thousand miles above , is what asthma looks like , what it is . so just a few key words to remember . we have airway constriction , in the small airway that causes shortness of breath and sounds like wheezing on a stethoscope .
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and this person coming in will be complaining of shortness of breath , so shortness-of-breath . sob is a very commonly used way to describe the symptom of ca n't catch your breath , panting , shortness of breath . now depending on how severe their attack is in the moment , a lot of people have rescue inhalers .
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is athsma cronical or is it just as you are a kid , and is athsma only where it is separate from a sickness or can it be a symptom ?
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when i first started thinking about this video , i realized that asthma is going to be hard to talk about because so many people have it , everybody knows at least a little bit about it , so it might be hard to get really to the bottom of what really is asthma . so , to do this , let 's go all the way back from the beginning . let 's just start by talking about the lungs , and what they look like and what they do . so , we have here your big trachea , and they branch off into your left and right bronchi . those are the two main stems of the lungs . and from there , they keep branching off like branches on a tree , and they get smaller and smaller . there are countless levels . i 'm gon na just try to draw a few levels here for us . so they keep branching off like this , you get the idea . when we inspire , or when we breathe in , inhaling , it 's kind of like a vacuum cleaner sucking air in . and these are all the tubes that are connected to it . so this is like the big hose . if you can imagine your vacuum breaks down into little hoses , that 's basically what it looks like . so in our lungs oxygen goes in , when we breathe in . o2 is oxygen , two oxygens . and then on the reverse side when we breathe out , we breathe out carbon dioxide , which is the symbol as co2 , one carbon and two oxygens . now asthma is classified as an obstructive disease where air is blocked on the way out , breathing out co2 . but we 'll get to that later exactly where that happens . for now if we are just looking at the set of tubes , otherwise known as our airway , and anywhere we go , if we take a cut like this across any of the tubes and we look at it up the tube , or we look at what is called a cross section of it , then it 's going to look something like this . so we have a round shape for the outside of the tube . and then we have an opening . and in the middle here we call it the lumen . the lumen is just the inside of any tube . this is where air actually goes through . and here in the walls of the airway , we have connective tissue , we have glands , we have all kinds of things . but i want to talk about this smooth muscle layer here that 's around in the wall of the airway . so since it 's a muscle , then it can have force and change the shape of things around it . so in asthma , what we care about is that the smooth muscles can actually constrict this airway . so to see what that looks like , let me draw this again here . again , if this is the outside of the wall , then a person who has active asthma happening at the moment , their airway 's going to be smaller , the lumen is going to be smaller , maybe about , let 's say this big . and what has happened , is that the smooth muscle around it is contracting hard and is clamping down on that lumen . to make matters even worse , when our body 's inflamed , it secretes fluid . so into the lumen , which is usually supposed to be open and dry , we have extra fluid . so when the opening is already smaller , it 's being flooded by mucous and fluid . and this whole picture together is what asthma looks like in our airways . now i just showed you one tube here , because we cut it once here . but imagine this process is happening in all these vacuum tubes , all these little levels . so the air is really having trouble moving . actually , if you could imagine a vacuum . let me just draw one here . this is the very primitive model of our vacuum . and if you could imagine that this machine has a lot of power sucking air in , but when it 's coming out , it 's a passive process , so there 's no power pushing the air out . so even though this constriction here will make it harder to suck air in , but at least it has a motor behind it , as opposed to when the air 's coming out , it just has to passively leave through the smaller straws . so that makes it harder on the exhale . we 'll come back to what that sounds like when we listen with the stethoscope . but first , let 's talk about what causes this process . why would your airway suddenly clamp down like that ? why would our body allow it , and what triggers it ? so i promise that every time i talk about lungs , the first thing i will always say is , smoking . smoking can be a huge trigger for asthma . does n't even have to be firsthand smoke , it can be secondhand . in fact , kids who have asthma , they 're exposed to parents who smoke in the house . even parents who are smoking outside , but then wear the same clothes inside the house . that can trigger asthma , because these smoke particles are billions and billions of little things that do n't belong in the lungs , and when they 're in there , this process can happen . also because we live in a time where there 's so much machinery around us , this is a car if you can tell ... so car exhaust and pollution in general in the cities can be a huge trigger for asthma . also people whose jobs expose them to things like asbestos , or other things they can inhale can be a trigger . i 'm just gon na start writing cause i ca n't draw fast enough . we have paint , remember that everybody has different triggers . people who have asthma do n't react the same way to the same things . and this one , i think , is really sad . some people can be triggered by food . you can be allergic to foods . or things in beer or wine , can trigger asthma in some people . now another trigger can be as common as stress . our body reacts to stress in a variety of ways . it can increase inflammation , which asthma is basically an inflammatory process . so this one i think is interesting . a common drug that most of us have probably taken , can be be a trigger in up to 30 percent of adults who take this drug , and that is aspirin . helps with your headaches , but sometimes causes your asthma to flare up . and lastly , babies who are completely different creatures from adults , they can have gi reflux , or what we call heartburn , where the things in their stomach go back up the esophagus . since they are so small , their system is so close together , it can go up the esophagus and into the trachea . so they can be triggered by gi reflux . as you can see , this reaches almost every aspect of life , this is probably why so many people have asthma , and it 's so different in everyone . so going back to our kind of clinical , medical way of thinking of asthma , if you are going to listen to a person breathe through your stethoscope , and this person has asthma , what might that sound like ? let me draw a stethoscope . are we gon na listen to these lungs ? now keep in mind , as i said earlier , there is fluid in here as well , so these smooth muscles constrict , but there 's also fluid and mucous getting secreted into these tubes as part of our body 's way of dealing with inflammation . so air and fluid together , what do they form ? they form air bubbles . so as these air bubbles pop and reform , and we 're trying to breathe through them , that 's why we would listen . we hear a high-pitched noise that 's referred to as wheezing . now wheezing is very characteristic of obstructive diseases , like asthma . wheezing basically sounds like a tiny little whistle , so when they inhale and then exhale , on the exhale you hear high-pitched noise all over the lung fields . now i 'm going to draw an imaginary line that divides our lung here . so the trachea , this is called the upper airway , and down here are the smaller airways . a wheezing in asthma is a small airway disease . it is a small airway disease that happens on the expiration , or when you breathe out . now if there 's noise on the inspiration , that 's usually caused by a foreign body , or some other kind of process that makes the upper airway constrict . that does n't really happen with asthma unless it 's super severe , and this person is just dying for breath . so usually asthma you can get an air in , and it 's on the expiration that we have a problem and you hear the wheezing . because again , the vacuum is sucking in air in the inspiration , so it 's going okay . but when you breathe out , passively , the restriction really causes a problem . so remember : asthma , wheezing , small airway disease . now this next part ... i do n't have asthma , so i always feel like i 'm not such a good judge on what it really feels like to have asthma . but we can imagine that if this person has trouble breathing out , breathing out is just as important as breathing in , if you ca n't do either it 's a very scary process . and this person coming in will be complaining of shortness of breath , so shortness-of-breath . sob is a very commonly used way to describe the symptom of ca n't catch your breath , panting , shortness of breath . now depending on how severe their attack is in the moment , a lot of people have rescue inhalers . when they 're panicking and ca n't breathe , this rescue inhaler can deliver some emergency drugs to open up that airway . and it 's such an important intervention for people who have asthma to not only breathe , but to feel like they can breathe , to help with the panic and just the discomfort of not being able to get a breath in and out . now lastly , i just want to mention that asthma , just from observation , seems to be related to two other diseases . there 's asthma , there 's eczema , which is a disease of the skin . you have excessively dry patches of skin that , again , flares up . it can be red-angry or dry and peely , a skin disease . and then the third , we have allergies , or some people call it allergic rhinitis , which is more proper for ( mumbling ) your nose , rhinitis . but most people are just calling it allergies . and these three things , for some reason seem to be good friends , in that a person who has one , is likely to have the other two . we do n't really do n't know why . we 're still studying why that relationship exists , but it does , especially in children . so this in a nutshell from a thousand miles above , is what asthma looks like , what it is . so just a few key words to remember . we have airway constriction , in the small airway that causes shortness of breath and sounds like wheezing on a stethoscope .
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now this next part ... i do n't have asthma , so i always feel like i 'm not such a good judge on what it really feels like to have asthma . but we can imagine that if this person has trouble breathing out , breathing out is just as important as breathing in , if you ca n't do either it 's a very scary process .
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what is it like to have asthma ?
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so today we 're gon na talk about co-dominance and incomplete dominance , but first let 's review the example of a blood type and how someone with the same two alleles coding for the same trait would be called homozygous and someone with different alleles would be called heterozygous . also remember , the concept of dominant and recessive alleles and how the a allele is dominant over the o allele in this example . this means that the same phenotype , blood type a , can result from these two different genotypes . now , the example that i just gave you was an example of complete dominance . so if a person had a genotype ao , since our phenotype is just blood type a , it means that the a allele is completely dominant over the o allele and only the a allele from the genotype is expressed in the phenotype . but there are actually three different patterns of dominance that i want you to be familiar with and to explain this i 'm going to use a different example . let 's say we have this flower and the red petal phenotype is coded for by the red r allele and the blue flower phenotype is coded for by the blue r allele . so i 'm going to introduce three different patterns of dominance and they are complete dominance , which you 've already heard of , co-dominance , and also incomplete dominance . i 'm going to explain what these two new patterns are through this flower example . let 's start by looking at three different genotypes and the phenotypes that you would see for each of them under each different dominance pattern . we 'll start with the genotype , two red rs , which we could expect that in all cases the flower petals will be red since we only have red rs in the genotype . similarly , if our genotype had two blue rs then we could expect that in all cases the flower petals will be blue since we only have blue rs in the genotype . now these three different dominance patterns change when we look at the heterozygous example . that 's what makes these three patterns different . now we 're already familiar with the example of complete dominance , so if we said that the red r is dominant over the blue r then this would make the heterozygous phenotype a red flower for complete dominance . now what co-dominance is , is when the heterozygous phenotype shows a flower with some red petals and some blue petals . so it 's when the two alleles are dominant together they are co-dominant and traits of both alleles show up in the phenotype . now what incomplete dominance is , is when the heterozygous phenotype shows a mixture of the two alleles . so in this case the red and blue flower petals may combine to form a purple flower . neither allele is completely dominant over the other and instead the two , being incompletely dominant , mix together . so what did we learn ? well , if we assume the heterozygous genotype , red r , blue r , then there are three different dominance patterns that we might see for a specific trait . in complete dominance , only one allele in the genotype , the dominant allele , is seen in the phenotype . and this was the example with the red flower . in co-dominance , both alleles in the genotype are seen in the phenotype . this was the example with the flower with both red and blue petals . finally , in incomplete dominance , a mixture of the alleles in the genotype is seen in the phenotype and this was the example with the purple flower .
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now , the example that i just gave you was an example of complete dominance . so if a person had a genotype ao , since our phenotype is just blood type a , it means that the a allele is completely dominant over the o allele and only the a allele from the genotype is expressed in the phenotype . but there are actually three different patterns of dominance that i want you to be familiar with and to explain this i 'm going to use a different example .
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what if there is a black person ( african american ) is half white ( caucasian ) what happens then ?
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so today we 're gon na talk about co-dominance and incomplete dominance , but first let 's review the example of a blood type and how someone with the same two alleles coding for the same trait would be called homozygous and someone with different alleles would be called heterozygous . also remember , the concept of dominant and recessive alleles and how the a allele is dominant over the o allele in this example . this means that the same phenotype , blood type a , can result from these two different genotypes . now , the example that i just gave you was an example of complete dominance . so if a person had a genotype ao , since our phenotype is just blood type a , it means that the a allele is completely dominant over the o allele and only the a allele from the genotype is expressed in the phenotype . but there are actually three different patterns of dominance that i want you to be familiar with and to explain this i 'm going to use a different example . let 's say we have this flower and the red petal phenotype is coded for by the red r allele and the blue flower phenotype is coded for by the blue r allele . so i 'm going to introduce three different patterns of dominance and they are complete dominance , which you 've already heard of , co-dominance , and also incomplete dominance . i 'm going to explain what these two new patterns are through this flower example . let 's start by looking at three different genotypes and the phenotypes that you would see for each of them under each different dominance pattern . we 'll start with the genotype , two red rs , which we could expect that in all cases the flower petals will be red since we only have red rs in the genotype . similarly , if our genotype had two blue rs then we could expect that in all cases the flower petals will be blue since we only have blue rs in the genotype . now these three different dominance patterns change when we look at the heterozygous example . that 's what makes these three patterns different . now we 're already familiar with the example of complete dominance , so if we said that the red r is dominant over the blue r then this would make the heterozygous phenotype a red flower for complete dominance . now what co-dominance is , is when the heterozygous phenotype shows a flower with some red petals and some blue petals . so it 's when the two alleles are dominant together they are co-dominant and traits of both alleles show up in the phenotype . now what incomplete dominance is , is when the heterozygous phenotype shows a mixture of the two alleles . so in this case the red and blue flower petals may combine to form a purple flower . neither allele is completely dominant over the other and instead the two , being incompletely dominant , mix together . so what did we learn ? well , if we assume the heterozygous genotype , red r , blue r , then there are three different dominance patterns that we might see for a specific trait . in complete dominance , only one allele in the genotype , the dominant allele , is seen in the phenotype . and this was the example with the red flower . in co-dominance , both alleles in the genotype are seen in the phenotype . this was the example with the flower with both red and blue petals . finally , in incomplete dominance , a mixture of the alleles in the genotype is seen in the phenotype and this was the example with the purple flower .
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now what co-dominance is , is when the heterozygous phenotype shows a flower with some red petals and some blue petals . so it 's when the two alleles are dominant together they are co-dominant and traits of both alleles show up in the phenotype . now what incomplete dominance is , is when the heterozygous phenotype shows a mixture of the two alleles .
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will recessive alleles be reflective in the phenotype ?
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so today we 're gon na talk about co-dominance and incomplete dominance , but first let 's review the example of a blood type and how someone with the same two alleles coding for the same trait would be called homozygous and someone with different alleles would be called heterozygous . also remember , the concept of dominant and recessive alleles and how the a allele is dominant over the o allele in this example . this means that the same phenotype , blood type a , can result from these two different genotypes . now , the example that i just gave you was an example of complete dominance . so if a person had a genotype ao , since our phenotype is just blood type a , it means that the a allele is completely dominant over the o allele and only the a allele from the genotype is expressed in the phenotype . but there are actually three different patterns of dominance that i want you to be familiar with and to explain this i 'm going to use a different example . let 's say we have this flower and the red petal phenotype is coded for by the red r allele and the blue flower phenotype is coded for by the blue r allele . so i 'm going to introduce three different patterns of dominance and they are complete dominance , which you 've already heard of , co-dominance , and also incomplete dominance . i 'm going to explain what these two new patterns are through this flower example . let 's start by looking at three different genotypes and the phenotypes that you would see for each of them under each different dominance pattern . we 'll start with the genotype , two red rs , which we could expect that in all cases the flower petals will be red since we only have red rs in the genotype . similarly , if our genotype had two blue rs then we could expect that in all cases the flower petals will be blue since we only have blue rs in the genotype . now these three different dominance patterns change when we look at the heterozygous example . that 's what makes these three patterns different . now we 're already familiar with the example of complete dominance , so if we said that the red r is dominant over the blue r then this would make the heterozygous phenotype a red flower for complete dominance . now what co-dominance is , is when the heterozygous phenotype shows a flower with some red petals and some blue petals . so it 's when the two alleles are dominant together they are co-dominant and traits of both alleles show up in the phenotype . now what incomplete dominance is , is when the heterozygous phenotype shows a mixture of the two alleles . so in this case the red and blue flower petals may combine to form a purple flower . neither allele is completely dominant over the other and instead the two , being incompletely dominant , mix together . so what did we learn ? well , if we assume the heterozygous genotype , red r , blue r , then there are three different dominance patterns that we might see for a specific trait . in complete dominance , only one allele in the genotype , the dominant allele , is seen in the phenotype . and this was the example with the red flower . in co-dominance , both alleles in the genotype are seen in the phenotype . this was the example with the flower with both red and blue petals . finally , in incomplete dominance , a mixture of the alleles in the genotype is seen in the phenotype and this was the example with the purple flower .
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let 's say we have this flower and the red petal phenotype is coded for by the red r allele and the blue flower phenotype is coded for by the blue r allele . so i 'm going to introduce three different patterns of dominance and they are complete dominance , which you 've already heard of , co-dominance , and also incomplete dominance . i 'm going to explain what these two new patterns are through this flower example .
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why does co-dominance and incomplete dominance happen ?
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so today we 're gon na talk about co-dominance and incomplete dominance , but first let 's review the example of a blood type and how someone with the same two alleles coding for the same trait would be called homozygous and someone with different alleles would be called heterozygous . also remember , the concept of dominant and recessive alleles and how the a allele is dominant over the o allele in this example . this means that the same phenotype , blood type a , can result from these two different genotypes . now , the example that i just gave you was an example of complete dominance . so if a person had a genotype ao , since our phenotype is just blood type a , it means that the a allele is completely dominant over the o allele and only the a allele from the genotype is expressed in the phenotype . but there are actually three different patterns of dominance that i want you to be familiar with and to explain this i 'm going to use a different example . let 's say we have this flower and the red petal phenotype is coded for by the red r allele and the blue flower phenotype is coded for by the blue r allele . so i 'm going to introduce three different patterns of dominance and they are complete dominance , which you 've already heard of , co-dominance , and also incomplete dominance . i 'm going to explain what these two new patterns are through this flower example . let 's start by looking at three different genotypes and the phenotypes that you would see for each of them under each different dominance pattern . we 'll start with the genotype , two red rs , which we could expect that in all cases the flower petals will be red since we only have red rs in the genotype . similarly , if our genotype had two blue rs then we could expect that in all cases the flower petals will be blue since we only have blue rs in the genotype . now these three different dominance patterns change when we look at the heterozygous example . that 's what makes these three patterns different . now we 're already familiar with the example of complete dominance , so if we said that the red r is dominant over the blue r then this would make the heterozygous phenotype a red flower for complete dominance . now what co-dominance is , is when the heterozygous phenotype shows a flower with some red petals and some blue petals . so it 's when the two alleles are dominant together they are co-dominant and traits of both alleles show up in the phenotype . now what incomplete dominance is , is when the heterozygous phenotype shows a mixture of the two alleles . so in this case the red and blue flower petals may combine to form a purple flower . neither allele is completely dominant over the other and instead the two , being incompletely dominant , mix together . so what did we learn ? well , if we assume the heterozygous genotype , red r , blue r , then there are three different dominance patterns that we might see for a specific trait . in complete dominance , only one allele in the genotype , the dominant allele , is seen in the phenotype . and this was the example with the red flower . in co-dominance , both alleles in the genotype are seen in the phenotype . this was the example with the flower with both red and blue petals . finally , in incomplete dominance , a mixture of the alleles in the genotype is seen in the phenotype and this was the example with the purple flower .
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let 's say we have this flower and the red petal phenotype is coded for by the red r allele and the blue flower phenotype is coded for by the blue r allele . so i 'm going to introduce three different patterns of dominance and they are complete dominance , which you 've already heard of , co-dominance , and also incomplete dominance . i 'm going to explain what these two new patterns are through this flower example .
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are n't codominance and incomplete dominance not considered a part of mendelian genetics ?
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so today we 're gon na talk about co-dominance and incomplete dominance , but first let 's review the example of a blood type and how someone with the same two alleles coding for the same trait would be called homozygous and someone with different alleles would be called heterozygous . also remember , the concept of dominant and recessive alleles and how the a allele is dominant over the o allele in this example . this means that the same phenotype , blood type a , can result from these two different genotypes . now , the example that i just gave you was an example of complete dominance . so if a person had a genotype ao , since our phenotype is just blood type a , it means that the a allele is completely dominant over the o allele and only the a allele from the genotype is expressed in the phenotype . but there are actually three different patterns of dominance that i want you to be familiar with and to explain this i 'm going to use a different example . let 's say we have this flower and the red petal phenotype is coded for by the red r allele and the blue flower phenotype is coded for by the blue r allele . so i 'm going to introduce three different patterns of dominance and they are complete dominance , which you 've already heard of , co-dominance , and also incomplete dominance . i 'm going to explain what these two new patterns are through this flower example . let 's start by looking at three different genotypes and the phenotypes that you would see for each of them under each different dominance pattern . we 'll start with the genotype , two red rs , which we could expect that in all cases the flower petals will be red since we only have red rs in the genotype . similarly , if our genotype had two blue rs then we could expect that in all cases the flower petals will be blue since we only have blue rs in the genotype . now these three different dominance patterns change when we look at the heterozygous example . that 's what makes these three patterns different . now we 're already familiar with the example of complete dominance , so if we said that the red r is dominant over the blue r then this would make the heterozygous phenotype a red flower for complete dominance . now what co-dominance is , is when the heterozygous phenotype shows a flower with some red petals and some blue petals . so it 's when the two alleles are dominant together they are co-dominant and traits of both alleles show up in the phenotype . now what incomplete dominance is , is when the heterozygous phenotype shows a mixture of the two alleles . so in this case the red and blue flower petals may combine to form a purple flower . neither allele is completely dominant over the other and instead the two , being incompletely dominant , mix together . so what did we learn ? well , if we assume the heterozygous genotype , red r , blue r , then there are three different dominance patterns that we might see for a specific trait . in complete dominance , only one allele in the genotype , the dominant allele , is seen in the phenotype . and this was the example with the red flower . in co-dominance , both alleles in the genotype are seen in the phenotype . this was the example with the flower with both red and blue petals . finally , in incomplete dominance , a mixture of the alleles in the genotype is seen in the phenotype and this was the example with the purple flower .
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so today we 're gon na talk about co-dominance and incomplete dominance , but first let 's review the example of a blood type and how someone with the same two alleles coding for the same trait would be called homozygous and someone with different alleles would be called heterozygous . also remember , the concept of dominant and recessive alleles and how the a allele is dominant over the o allele in this example . this means that the same phenotype , blood type a , can result from these two different genotypes .
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is n't a dominant trait represented by a capital letter ( b ) and a recessive trait represented by a lower case letter ( b ) ?
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so today we 're gon na talk about co-dominance and incomplete dominance , but first let 's review the example of a blood type and how someone with the same two alleles coding for the same trait would be called homozygous and someone with different alleles would be called heterozygous . also remember , the concept of dominant and recessive alleles and how the a allele is dominant over the o allele in this example . this means that the same phenotype , blood type a , can result from these two different genotypes . now , the example that i just gave you was an example of complete dominance . so if a person had a genotype ao , since our phenotype is just blood type a , it means that the a allele is completely dominant over the o allele and only the a allele from the genotype is expressed in the phenotype . but there are actually three different patterns of dominance that i want you to be familiar with and to explain this i 'm going to use a different example . let 's say we have this flower and the red petal phenotype is coded for by the red r allele and the blue flower phenotype is coded for by the blue r allele . so i 'm going to introduce three different patterns of dominance and they are complete dominance , which you 've already heard of , co-dominance , and also incomplete dominance . i 'm going to explain what these two new patterns are through this flower example . let 's start by looking at three different genotypes and the phenotypes that you would see for each of them under each different dominance pattern . we 'll start with the genotype , two red rs , which we could expect that in all cases the flower petals will be red since we only have red rs in the genotype . similarly , if our genotype had two blue rs then we could expect that in all cases the flower petals will be blue since we only have blue rs in the genotype . now these three different dominance patterns change when we look at the heterozygous example . that 's what makes these three patterns different . now we 're already familiar with the example of complete dominance , so if we said that the red r is dominant over the blue r then this would make the heterozygous phenotype a red flower for complete dominance . now what co-dominance is , is when the heterozygous phenotype shows a flower with some red petals and some blue petals . so it 's when the two alleles are dominant together they are co-dominant and traits of both alleles show up in the phenotype . now what incomplete dominance is , is when the heterozygous phenotype shows a mixture of the two alleles . so in this case the red and blue flower petals may combine to form a purple flower . neither allele is completely dominant over the other and instead the two , being incompletely dominant , mix together . so what did we learn ? well , if we assume the heterozygous genotype , red r , blue r , then there are three different dominance patterns that we might see for a specific trait . in complete dominance , only one allele in the genotype , the dominant allele , is seen in the phenotype . and this was the example with the red flower . in co-dominance , both alleles in the genotype are seen in the phenotype . this was the example with the flower with both red and blue petals . finally , in incomplete dominance , a mixture of the alleles in the genotype is seen in the phenotype and this was the example with the purple flower .
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let 's say we have this flower and the red petal phenotype is coded for by the red r allele and the blue flower phenotype is coded for by the blue r allele . so i 'm going to introduce three different patterns of dominance and they are complete dominance , which you 've already heard of , co-dominance , and also incomplete dominance . i 'm going to explain what these two new patterns are through this flower example .
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are co dominance and incomplete dominance seen in blood type ?
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organisms that reproduce sexually have got to get their genes together somehow . to do this , they package their genetic material into specialized cells called sex cells . this is the sperm cell . it 's the sex cell of the male . the sole purpose of the sperm , the entire reason for its existence , is to transfer the male 's genetic material into the female sex cell or the egg . so the sperm cell is packed with features that allow it to fulfill its job . it 's basically a little torpedo . you can see , just like a torpedo , it has a pointed head which allows it to travel in the forward direction . at the back end it has the tail , and the tail is just a flagellum , and as the flagellum spins it acts like a little propeller . and then it has a middle section . now within that middle section , wrapped around the base of the flagellar tail , are all of these little organelles called mitochondria . you can see i 'm drawing these mitochondria wrapped around the flagellar base here . and mitochondria are organelles that are responsible for giving energy to a cell . and the sperm cell has a whole bunch packed right into the base of the flagellum here . probably 75 to 100 , and they 're quite large mitochondria . in fact , these mitochondria are often fused together to create big organelles . and the reason is because in order to propel the sperm torpedo towards the egg , it needs a lot of energy . and that all comes from these mitochondria . now the payload of the torpedo is here in the head , and that 's the genetic material , our dna within the nucleus . i 'll draw it kind of all coiled back here . and here 's the nuclear envelope here . and just like any regular torpedo , the sperm torpedo has a warhead right in the front . and that warhead is a little collection of enzymes called the acrosome . and the acrosome is gon na be important later on for fertilization . but that 's pretty much it . there 's a tail at the back to provide propulsion , some mitochondria in the middle section to give energy to the tail , a head which contains the nuclear material , and the acrosome . this is a pretty bare bones cell . it 's designed to move fast and to get to the egg . there are no bells and whistles here . now that 's in contrast to the egg cell . now the first thing you 'll notice is that the egg cell is round , unlike the torpedo shape of the sperm cell . this is not a cell that 's made for active mobility . the second thing is that the egg cell is huge compared to the sperm cell . it 's so big , in fact , that it 's almost visible . in fact , sometimes it is visible to the human eye . now compared to the sperm cell , which i 'll draw in here , the egg cell is about 10,000 times more massive . and similar to the sperm cell , the egg cell has its share of genetic material ready to combine during fertilization . you can see it here within the nucleus . and so you may have noticed this thick outer coating on the egg cell here , that 's a very important structure called the zona pellucida . and the zona pellucida is a thick layer of glycoproteins that sit on the outside of the egg . and glycoproteins are basically a protein , i 'll draw a protein here in green , with a whole bunch of branching sugar chains that are coming off of them . and so what this looks like is basically a little tree or a long branching thing that 's growing out of the edge of the egg cell . and there 's a whole bunch of them , and they form this very thick kind of protective layer that the sperm has to get through . and the edge of the egg cell is the actual plasma membrane . and once the sperm can deliver its genetic material beyond that , fertilization has occurred . now there 's a whole bunch of other structures within the egg cytoplasm as well . and remember this thing is huge . and i 'm gon na draw in a few here in green . now what i 'm drawing in are actually more mitochondria . now remember the egg cell had 75 to 100 big mitochondria right at the base of the flagellum to provide energy to drive locomotion . well , the egg cell has mitochondria too . it 's got a lot of other different organelles as well . but the egg cell is so large , it 's got somewhere between 100 and 200 thousand mitochondria present . so keep those mitochondria in mind , we 'll talk about them a little bit later in the next section . so now that you 've met the two major players here , the sperm and the egg , or the male and female sex cells respectively , we can talk about what happens when they meet . and that process is called fertilization . so we 'll go ahead and label our egg down here . and we 'll put a quick label on this as well . this is the zona pellucida that we talked about earlier . so we 'll draw the sperm here coming in to meet the egg . we 'll draw its tail . we 'll draw its middle section here . and we 'll draw its torpedo-like head here . get rid of all this zona pellucida glycoprotein in the middle here . now here are the mitochondria in the middle section here , and we have the genetic material payload of our sperm torpedo here in the back , and our acrosome here in the front . now the first thing that happens during fertilization is that the sperm comes into contact with the zona pellucida . and the zona pellucida actually binds to the outside of the sperm , and that 's called sperm binding . and it 's step number one . now what happens when the sperm gets bound to the zona pellucida is that that sets up a reaction called the acrosomal reaction . so step number two is called the acrosome reaction . and that little warhead tip of the sperm torpedo gets released , and so we have all of the acrosomal enzymes that were sitting in the head that just kind of leak out into that zona pellucida . and as those enzymes leak out , they actually start to digest away the zona pellucida . here you can see i 'm kind of eating away here at those glycoprotein , and that allows the sperm head to dive in deeper towards our plasma membrane . now as the sperm gets closer to the plasma membrane of the egg , and it comes in contact right here , it starts up a process of binding . the two touch and they come together . and as they start together , it causes another reaction , and that third reaction is called cortical reaction . and what i have n't drawn here is another structure in the egg , and those structures are right underneath the plasma membrane , and they just sit there waiting . and they wait and their entire job is to wait for a sperm to bind . and as soon as a single sperm binds , they get ejected out into that zone pellucida as well . just like the acrosomal enzymes , these enzymes that are contained within the cortical granules also start eating away at the zona pellucida . these enzymes eat away , and they dissolve and chew up these glycoproteins , but specifically they chew up the glycoprotein that allows sperm to bind . so at this point we have a single sperm that 's bound , set off the cortical reaction , and these cortical granules are released that chew up all the other places that more sperm can bind . so as our other sperm torpedoes are coming in , they 're just bouncing off . they hit the glycoproteins , but the one that they need to bind to is n't there because it 's all been chewed up and degraded by these cortical granules . so that 's actually called a block to polyspermy . now that 's a very important concept . polyspermy is a term that just means multiple sperm . and what we do n't want is for more than one sperm to inject its nuclear material , its dna into this egg . what you 'd end up with is an egg with a single contribution from mom and then one or two or three or 100 contributions or genetic material from dad . and that would never work , you 'd end up with all sorts of problems as the egg started to divide . occasionally , that does happen , and it can result in a zygote that fails . but for the most part , as these cortical granules dissolve away all the sperm binding glycoproteins of the zona pellucida , other sperm just ca n't get in and they bounce off as they arrive . so now we have a sperm that 's made its way all the way to the plasma membrane of our egg cell . it 's started to bind to the plasma membrane , the acrosome is gone , i 'll erase that here . it 's done its job . the cortical granules have been released , and they 're preventing other sperm from getting in . and we start to actually fuse our plasma membranes of our sperm cell and our egg cell . and that allows for this entire structure to come in . all of the genetic material here within the , all of the genetic material within the nucleus of the sperm cell can start to come out and get released here into the egg . and once we have fusion of genetic material , that is fertilization . so just to recap , we 'll go back to look at our close-up of our sperm . we can see that it 's a very mobile structure evolved basically to get genetic material from the male to the female egg cell . it 's got a tail that propulses it , it 's got mitochondria that feed it energy , it 's got a head with a payload of nuclear material and an acrosome warhead on the tip . the egg cell is a giant cell by comparison . it 's got a specialized layer of glycoproteins on the outside that have a bunch of specialized features and then a bunch of cytoplasm , including mitochondria . and then the process of egg meeting sperm itself is called fertilization . sperm binds to the zona pellucida , the glycoproteins , you have an acrosomal reaction , and then a cortical reaction prevents more than one sperm getting in . and then material , the genetic material of the sperm is transferred . now you 'll notice here that i drew the genetic material from the nucleus coming in . now some of you may be wondering , `` well do n't mitochondria have genetic material as well ? '' well , that 's true . mitochondria do have mitochondrial dna . and potentially , some of these mitochondria can get sucked in during that genetic transfer process as well . but remember , our egg cell had 100 to 200 thousand mitochondrial copies , and our sperm cell only had 75 to 100 . now there 's a little bit of debate , but in the end the male contributes essentially no mitochondria to the zygote that 's formed after the egg and sperm fuse . now , it could be that some of those mitochondria actually do make their way in and then are degraded . we 're not really sure . but given just the numbers , statistically with one to two hundred thousand versus only 75 to 100 , nearly all of the genetic material from the mitochondria is gon na be from the mother anyway .
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but for the most part , as these cortical granules dissolve away all the sperm binding glycoproteins of the zona pellucida , other sperm just ca n't get in and they bounce off as they arrive . so now we have a sperm that 's made its way all the way to the plasma membrane of our egg cell . it 's started to bind to the plasma membrane , the acrosome is gone , i 'll erase that here .
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how do sperm make their way through the corona radiata ?
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organisms that reproduce sexually have got to get their genes together somehow . to do this , they package their genetic material into specialized cells called sex cells . this is the sperm cell . it 's the sex cell of the male . the sole purpose of the sperm , the entire reason for its existence , is to transfer the male 's genetic material into the female sex cell or the egg . so the sperm cell is packed with features that allow it to fulfill its job . it 's basically a little torpedo . you can see , just like a torpedo , it has a pointed head which allows it to travel in the forward direction . at the back end it has the tail , and the tail is just a flagellum , and as the flagellum spins it acts like a little propeller . and then it has a middle section . now within that middle section , wrapped around the base of the flagellar tail , are all of these little organelles called mitochondria . you can see i 'm drawing these mitochondria wrapped around the flagellar base here . and mitochondria are organelles that are responsible for giving energy to a cell . and the sperm cell has a whole bunch packed right into the base of the flagellum here . probably 75 to 100 , and they 're quite large mitochondria . in fact , these mitochondria are often fused together to create big organelles . and the reason is because in order to propel the sperm torpedo towards the egg , it needs a lot of energy . and that all comes from these mitochondria . now the payload of the torpedo is here in the head , and that 's the genetic material , our dna within the nucleus . i 'll draw it kind of all coiled back here . and here 's the nuclear envelope here . and just like any regular torpedo , the sperm torpedo has a warhead right in the front . and that warhead is a little collection of enzymes called the acrosome . and the acrosome is gon na be important later on for fertilization . but that 's pretty much it . there 's a tail at the back to provide propulsion , some mitochondria in the middle section to give energy to the tail , a head which contains the nuclear material , and the acrosome . this is a pretty bare bones cell . it 's designed to move fast and to get to the egg . there are no bells and whistles here . now that 's in contrast to the egg cell . now the first thing you 'll notice is that the egg cell is round , unlike the torpedo shape of the sperm cell . this is not a cell that 's made for active mobility . the second thing is that the egg cell is huge compared to the sperm cell . it 's so big , in fact , that it 's almost visible . in fact , sometimes it is visible to the human eye . now compared to the sperm cell , which i 'll draw in here , the egg cell is about 10,000 times more massive . and similar to the sperm cell , the egg cell has its share of genetic material ready to combine during fertilization . you can see it here within the nucleus . and so you may have noticed this thick outer coating on the egg cell here , that 's a very important structure called the zona pellucida . and the zona pellucida is a thick layer of glycoproteins that sit on the outside of the egg . and glycoproteins are basically a protein , i 'll draw a protein here in green , with a whole bunch of branching sugar chains that are coming off of them . and so what this looks like is basically a little tree or a long branching thing that 's growing out of the edge of the egg cell . and there 's a whole bunch of them , and they form this very thick kind of protective layer that the sperm has to get through . and the edge of the egg cell is the actual plasma membrane . and once the sperm can deliver its genetic material beyond that , fertilization has occurred . now there 's a whole bunch of other structures within the egg cytoplasm as well . and remember this thing is huge . and i 'm gon na draw in a few here in green . now what i 'm drawing in are actually more mitochondria . now remember the egg cell had 75 to 100 big mitochondria right at the base of the flagellum to provide energy to drive locomotion . well , the egg cell has mitochondria too . it 's got a lot of other different organelles as well . but the egg cell is so large , it 's got somewhere between 100 and 200 thousand mitochondria present . so keep those mitochondria in mind , we 'll talk about them a little bit later in the next section . so now that you 've met the two major players here , the sperm and the egg , or the male and female sex cells respectively , we can talk about what happens when they meet . and that process is called fertilization . so we 'll go ahead and label our egg down here . and we 'll put a quick label on this as well . this is the zona pellucida that we talked about earlier . so we 'll draw the sperm here coming in to meet the egg . we 'll draw its tail . we 'll draw its middle section here . and we 'll draw its torpedo-like head here . get rid of all this zona pellucida glycoprotein in the middle here . now here are the mitochondria in the middle section here , and we have the genetic material payload of our sperm torpedo here in the back , and our acrosome here in the front . now the first thing that happens during fertilization is that the sperm comes into contact with the zona pellucida . and the zona pellucida actually binds to the outside of the sperm , and that 's called sperm binding . and it 's step number one . now what happens when the sperm gets bound to the zona pellucida is that that sets up a reaction called the acrosomal reaction . so step number two is called the acrosome reaction . and that little warhead tip of the sperm torpedo gets released , and so we have all of the acrosomal enzymes that were sitting in the head that just kind of leak out into that zona pellucida . and as those enzymes leak out , they actually start to digest away the zona pellucida . here you can see i 'm kind of eating away here at those glycoprotein , and that allows the sperm head to dive in deeper towards our plasma membrane . now as the sperm gets closer to the plasma membrane of the egg , and it comes in contact right here , it starts up a process of binding . the two touch and they come together . and as they start together , it causes another reaction , and that third reaction is called cortical reaction . and what i have n't drawn here is another structure in the egg , and those structures are right underneath the plasma membrane , and they just sit there waiting . and they wait and their entire job is to wait for a sperm to bind . and as soon as a single sperm binds , they get ejected out into that zone pellucida as well . just like the acrosomal enzymes , these enzymes that are contained within the cortical granules also start eating away at the zona pellucida . these enzymes eat away , and they dissolve and chew up these glycoproteins , but specifically they chew up the glycoprotein that allows sperm to bind . so at this point we have a single sperm that 's bound , set off the cortical reaction , and these cortical granules are released that chew up all the other places that more sperm can bind . so as our other sperm torpedoes are coming in , they 're just bouncing off . they hit the glycoproteins , but the one that they need to bind to is n't there because it 's all been chewed up and degraded by these cortical granules . so that 's actually called a block to polyspermy . now that 's a very important concept . polyspermy is a term that just means multiple sperm . and what we do n't want is for more than one sperm to inject its nuclear material , its dna into this egg . what you 'd end up with is an egg with a single contribution from mom and then one or two or three or 100 contributions or genetic material from dad . and that would never work , you 'd end up with all sorts of problems as the egg started to divide . occasionally , that does happen , and it can result in a zygote that fails . but for the most part , as these cortical granules dissolve away all the sperm binding glycoproteins of the zona pellucida , other sperm just ca n't get in and they bounce off as they arrive . so now we have a sperm that 's made its way all the way to the plasma membrane of our egg cell . it 's started to bind to the plasma membrane , the acrosome is gone , i 'll erase that here . it 's done its job . the cortical granules have been released , and they 're preventing other sperm from getting in . and we start to actually fuse our plasma membranes of our sperm cell and our egg cell . and that allows for this entire structure to come in . all of the genetic material here within the , all of the genetic material within the nucleus of the sperm cell can start to come out and get released here into the egg . and once we have fusion of genetic material , that is fertilization . so just to recap , we 'll go back to look at our close-up of our sperm . we can see that it 's a very mobile structure evolved basically to get genetic material from the male to the female egg cell . it 's got a tail that propulses it , it 's got mitochondria that feed it energy , it 's got a head with a payload of nuclear material and an acrosome warhead on the tip . the egg cell is a giant cell by comparison . it 's got a specialized layer of glycoproteins on the outside that have a bunch of specialized features and then a bunch of cytoplasm , including mitochondria . and then the process of egg meeting sperm itself is called fertilization . sperm binds to the zona pellucida , the glycoproteins , you have an acrosomal reaction , and then a cortical reaction prevents more than one sperm getting in . and then material , the genetic material of the sperm is transferred . now you 'll notice here that i drew the genetic material from the nucleus coming in . now some of you may be wondering , `` well do n't mitochondria have genetic material as well ? '' well , that 's true . mitochondria do have mitochondrial dna . and potentially , some of these mitochondria can get sucked in during that genetic transfer process as well . but remember , our egg cell had 100 to 200 thousand mitochondrial copies , and our sperm cell only had 75 to 100 . now there 's a little bit of debate , but in the end the male contributes essentially no mitochondria to the zygote that 's formed after the egg and sperm fuse . now , it could be that some of those mitochondria actually do make their way in and then are degraded . we 're not really sure . but given just the numbers , statistically with one to two hundred thousand versus only 75 to 100 , nearly all of the genetic material from the mitochondria is gon na be from the mother anyway .
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the cortical granules have been released , and they 're preventing other sperm from getting in . and we start to actually fuse our plasma membranes of our sperm cell and our egg cell . and that allows for this entire structure to come in .
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what incites the fusion of sperm and egg membranes ?
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organisms that reproduce sexually have got to get their genes together somehow . to do this , they package their genetic material into specialized cells called sex cells . this is the sperm cell . it 's the sex cell of the male . the sole purpose of the sperm , the entire reason for its existence , is to transfer the male 's genetic material into the female sex cell or the egg . so the sperm cell is packed with features that allow it to fulfill its job . it 's basically a little torpedo . you can see , just like a torpedo , it has a pointed head which allows it to travel in the forward direction . at the back end it has the tail , and the tail is just a flagellum , and as the flagellum spins it acts like a little propeller . and then it has a middle section . now within that middle section , wrapped around the base of the flagellar tail , are all of these little organelles called mitochondria . you can see i 'm drawing these mitochondria wrapped around the flagellar base here . and mitochondria are organelles that are responsible for giving energy to a cell . and the sperm cell has a whole bunch packed right into the base of the flagellum here . probably 75 to 100 , and they 're quite large mitochondria . in fact , these mitochondria are often fused together to create big organelles . and the reason is because in order to propel the sperm torpedo towards the egg , it needs a lot of energy . and that all comes from these mitochondria . now the payload of the torpedo is here in the head , and that 's the genetic material , our dna within the nucleus . i 'll draw it kind of all coiled back here . and here 's the nuclear envelope here . and just like any regular torpedo , the sperm torpedo has a warhead right in the front . and that warhead is a little collection of enzymes called the acrosome . and the acrosome is gon na be important later on for fertilization . but that 's pretty much it . there 's a tail at the back to provide propulsion , some mitochondria in the middle section to give energy to the tail , a head which contains the nuclear material , and the acrosome . this is a pretty bare bones cell . it 's designed to move fast and to get to the egg . there are no bells and whistles here . now that 's in contrast to the egg cell . now the first thing you 'll notice is that the egg cell is round , unlike the torpedo shape of the sperm cell . this is not a cell that 's made for active mobility . the second thing is that the egg cell is huge compared to the sperm cell . it 's so big , in fact , that it 's almost visible . in fact , sometimes it is visible to the human eye . now compared to the sperm cell , which i 'll draw in here , the egg cell is about 10,000 times more massive . and similar to the sperm cell , the egg cell has its share of genetic material ready to combine during fertilization . you can see it here within the nucleus . and so you may have noticed this thick outer coating on the egg cell here , that 's a very important structure called the zona pellucida . and the zona pellucida is a thick layer of glycoproteins that sit on the outside of the egg . and glycoproteins are basically a protein , i 'll draw a protein here in green , with a whole bunch of branching sugar chains that are coming off of them . and so what this looks like is basically a little tree or a long branching thing that 's growing out of the edge of the egg cell . and there 's a whole bunch of them , and they form this very thick kind of protective layer that the sperm has to get through . and the edge of the egg cell is the actual plasma membrane . and once the sperm can deliver its genetic material beyond that , fertilization has occurred . now there 's a whole bunch of other structures within the egg cytoplasm as well . and remember this thing is huge . and i 'm gon na draw in a few here in green . now what i 'm drawing in are actually more mitochondria . now remember the egg cell had 75 to 100 big mitochondria right at the base of the flagellum to provide energy to drive locomotion . well , the egg cell has mitochondria too . it 's got a lot of other different organelles as well . but the egg cell is so large , it 's got somewhere between 100 and 200 thousand mitochondria present . so keep those mitochondria in mind , we 'll talk about them a little bit later in the next section . so now that you 've met the two major players here , the sperm and the egg , or the male and female sex cells respectively , we can talk about what happens when they meet . and that process is called fertilization . so we 'll go ahead and label our egg down here . and we 'll put a quick label on this as well . this is the zona pellucida that we talked about earlier . so we 'll draw the sperm here coming in to meet the egg . we 'll draw its tail . we 'll draw its middle section here . and we 'll draw its torpedo-like head here . get rid of all this zona pellucida glycoprotein in the middle here . now here are the mitochondria in the middle section here , and we have the genetic material payload of our sperm torpedo here in the back , and our acrosome here in the front . now the first thing that happens during fertilization is that the sperm comes into contact with the zona pellucida . and the zona pellucida actually binds to the outside of the sperm , and that 's called sperm binding . and it 's step number one . now what happens when the sperm gets bound to the zona pellucida is that that sets up a reaction called the acrosomal reaction . so step number two is called the acrosome reaction . and that little warhead tip of the sperm torpedo gets released , and so we have all of the acrosomal enzymes that were sitting in the head that just kind of leak out into that zona pellucida . and as those enzymes leak out , they actually start to digest away the zona pellucida . here you can see i 'm kind of eating away here at those glycoprotein , and that allows the sperm head to dive in deeper towards our plasma membrane . now as the sperm gets closer to the plasma membrane of the egg , and it comes in contact right here , it starts up a process of binding . the two touch and they come together . and as they start together , it causes another reaction , and that third reaction is called cortical reaction . and what i have n't drawn here is another structure in the egg , and those structures are right underneath the plasma membrane , and they just sit there waiting . and they wait and their entire job is to wait for a sperm to bind . and as soon as a single sperm binds , they get ejected out into that zone pellucida as well . just like the acrosomal enzymes , these enzymes that are contained within the cortical granules also start eating away at the zona pellucida . these enzymes eat away , and they dissolve and chew up these glycoproteins , but specifically they chew up the glycoprotein that allows sperm to bind . so at this point we have a single sperm that 's bound , set off the cortical reaction , and these cortical granules are released that chew up all the other places that more sperm can bind . so as our other sperm torpedoes are coming in , they 're just bouncing off . they hit the glycoproteins , but the one that they need to bind to is n't there because it 's all been chewed up and degraded by these cortical granules . so that 's actually called a block to polyspermy . now that 's a very important concept . polyspermy is a term that just means multiple sperm . and what we do n't want is for more than one sperm to inject its nuclear material , its dna into this egg . what you 'd end up with is an egg with a single contribution from mom and then one or two or three or 100 contributions or genetic material from dad . and that would never work , you 'd end up with all sorts of problems as the egg started to divide . occasionally , that does happen , and it can result in a zygote that fails . but for the most part , as these cortical granules dissolve away all the sperm binding glycoproteins of the zona pellucida , other sperm just ca n't get in and they bounce off as they arrive . so now we have a sperm that 's made its way all the way to the plasma membrane of our egg cell . it 's started to bind to the plasma membrane , the acrosome is gone , i 'll erase that here . it 's done its job . the cortical granules have been released , and they 're preventing other sperm from getting in . and we start to actually fuse our plasma membranes of our sperm cell and our egg cell . and that allows for this entire structure to come in . all of the genetic material here within the , all of the genetic material within the nucleus of the sperm cell can start to come out and get released here into the egg . and once we have fusion of genetic material , that is fertilization . so just to recap , we 'll go back to look at our close-up of our sperm . we can see that it 's a very mobile structure evolved basically to get genetic material from the male to the female egg cell . it 's got a tail that propulses it , it 's got mitochondria that feed it energy , it 's got a head with a payload of nuclear material and an acrosome warhead on the tip . the egg cell is a giant cell by comparison . it 's got a specialized layer of glycoproteins on the outside that have a bunch of specialized features and then a bunch of cytoplasm , including mitochondria . and then the process of egg meeting sperm itself is called fertilization . sperm binds to the zona pellucida , the glycoproteins , you have an acrosomal reaction , and then a cortical reaction prevents more than one sperm getting in . and then material , the genetic material of the sperm is transferred . now you 'll notice here that i drew the genetic material from the nucleus coming in . now some of you may be wondering , `` well do n't mitochondria have genetic material as well ? '' well , that 's true . mitochondria do have mitochondrial dna . and potentially , some of these mitochondria can get sucked in during that genetic transfer process as well . but remember , our egg cell had 100 to 200 thousand mitochondrial copies , and our sperm cell only had 75 to 100 . now there 's a little bit of debate , but in the end the male contributes essentially no mitochondria to the zygote that 's formed after the egg and sperm fuse . now , it could be that some of those mitochondria actually do make their way in and then are degraded . we 're not really sure . but given just the numbers , statistically with one to two hundred thousand versus only 75 to 100 , nearly all of the genetic material from the mitochondria is gon na be from the mother anyway .
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sperm binds to the zona pellucida , the glycoproteins , you have an acrosomal reaction , and then a cortical reaction prevents more than one sperm getting in . and then material , the genetic material of the sperm is transferred . now you 'll notice here that i drew the genetic material from the nucleus coming in .
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does the sperm 's genetic material really just float into the egg all random-y , or does it have a nuclear envelope ?
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organisms that reproduce sexually have got to get their genes together somehow . to do this , they package their genetic material into specialized cells called sex cells . this is the sperm cell . it 's the sex cell of the male . the sole purpose of the sperm , the entire reason for its existence , is to transfer the male 's genetic material into the female sex cell or the egg . so the sperm cell is packed with features that allow it to fulfill its job . it 's basically a little torpedo . you can see , just like a torpedo , it has a pointed head which allows it to travel in the forward direction . at the back end it has the tail , and the tail is just a flagellum , and as the flagellum spins it acts like a little propeller . and then it has a middle section . now within that middle section , wrapped around the base of the flagellar tail , are all of these little organelles called mitochondria . you can see i 'm drawing these mitochondria wrapped around the flagellar base here . and mitochondria are organelles that are responsible for giving energy to a cell . and the sperm cell has a whole bunch packed right into the base of the flagellum here . probably 75 to 100 , and they 're quite large mitochondria . in fact , these mitochondria are often fused together to create big organelles . and the reason is because in order to propel the sperm torpedo towards the egg , it needs a lot of energy . and that all comes from these mitochondria . now the payload of the torpedo is here in the head , and that 's the genetic material , our dna within the nucleus . i 'll draw it kind of all coiled back here . and here 's the nuclear envelope here . and just like any regular torpedo , the sperm torpedo has a warhead right in the front . and that warhead is a little collection of enzymes called the acrosome . and the acrosome is gon na be important later on for fertilization . but that 's pretty much it . there 's a tail at the back to provide propulsion , some mitochondria in the middle section to give energy to the tail , a head which contains the nuclear material , and the acrosome . this is a pretty bare bones cell . it 's designed to move fast and to get to the egg . there are no bells and whistles here . now that 's in contrast to the egg cell . now the first thing you 'll notice is that the egg cell is round , unlike the torpedo shape of the sperm cell . this is not a cell that 's made for active mobility . the second thing is that the egg cell is huge compared to the sperm cell . it 's so big , in fact , that it 's almost visible . in fact , sometimes it is visible to the human eye . now compared to the sperm cell , which i 'll draw in here , the egg cell is about 10,000 times more massive . and similar to the sperm cell , the egg cell has its share of genetic material ready to combine during fertilization . you can see it here within the nucleus . and so you may have noticed this thick outer coating on the egg cell here , that 's a very important structure called the zona pellucida . and the zona pellucida is a thick layer of glycoproteins that sit on the outside of the egg . and glycoproteins are basically a protein , i 'll draw a protein here in green , with a whole bunch of branching sugar chains that are coming off of them . and so what this looks like is basically a little tree or a long branching thing that 's growing out of the edge of the egg cell . and there 's a whole bunch of them , and they form this very thick kind of protective layer that the sperm has to get through . and the edge of the egg cell is the actual plasma membrane . and once the sperm can deliver its genetic material beyond that , fertilization has occurred . now there 's a whole bunch of other structures within the egg cytoplasm as well . and remember this thing is huge . and i 'm gon na draw in a few here in green . now what i 'm drawing in are actually more mitochondria . now remember the egg cell had 75 to 100 big mitochondria right at the base of the flagellum to provide energy to drive locomotion . well , the egg cell has mitochondria too . it 's got a lot of other different organelles as well . but the egg cell is so large , it 's got somewhere between 100 and 200 thousand mitochondria present . so keep those mitochondria in mind , we 'll talk about them a little bit later in the next section . so now that you 've met the two major players here , the sperm and the egg , or the male and female sex cells respectively , we can talk about what happens when they meet . and that process is called fertilization . so we 'll go ahead and label our egg down here . and we 'll put a quick label on this as well . this is the zona pellucida that we talked about earlier . so we 'll draw the sperm here coming in to meet the egg . we 'll draw its tail . we 'll draw its middle section here . and we 'll draw its torpedo-like head here . get rid of all this zona pellucida glycoprotein in the middle here . now here are the mitochondria in the middle section here , and we have the genetic material payload of our sperm torpedo here in the back , and our acrosome here in the front . now the first thing that happens during fertilization is that the sperm comes into contact with the zona pellucida . and the zona pellucida actually binds to the outside of the sperm , and that 's called sperm binding . and it 's step number one . now what happens when the sperm gets bound to the zona pellucida is that that sets up a reaction called the acrosomal reaction . so step number two is called the acrosome reaction . and that little warhead tip of the sperm torpedo gets released , and so we have all of the acrosomal enzymes that were sitting in the head that just kind of leak out into that zona pellucida . and as those enzymes leak out , they actually start to digest away the zona pellucida . here you can see i 'm kind of eating away here at those glycoprotein , and that allows the sperm head to dive in deeper towards our plasma membrane . now as the sperm gets closer to the plasma membrane of the egg , and it comes in contact right here , it starts up a process of binding . the two touch and they come together . and as they start together , it causes another reaction , and that third reaction is called cortical reaction . and what i have n't drawn here is another structure in the egg , and those structures are right underneath the plasma membrane , and they just sit there waiting . and they wait and their entire job is to wait for a sperm to bind . and as soon as a single sperm binds , they get ejected out into that zone pellucida as well . just like the acrosomal enzymes , these enzymes that are contained within the cortical granules also start eating away at the zona pellucida . these enzymes eat away , and they dissolve and chew up these glycoproteins , but specifically they chew up the glycoprotein that allows sperm to bind . so at this point we have a single sperm that 's bound , set off the cortical reaction , and these cortical granules are released that chew up all the other places that more sperm can bind . so as our other sperm torpedoes are coming in , they 're just bouncing off . they hit the glycoproteins , but the one that they need to bind to is n't there because it 's all been chewed up and degraded by these cortical granules . so that 's actually called a block to polyspermy . now that 's a very important concept . polyspermy is a term that just means multiple sperm . and what we do n't want is for more than one sperm to inject its nuclear material , its dna into this egg . what you 'd end up with is an egg with a single contribution from mom and then one or two or three or 100 contributions or genetic material from dad . and that would never work , you 'd end up with all sorts of problems as the egg started to divide . occasionally , that does happen , and it can result in a zygote that fails . but for the most part , as these cortical granules dissolve away all the sperm binding glycoproteins of the zona pellucida , other sperm just ca n't get in and they bounce off as they arrive . so now we have a sperm that 's made its way all the way to the plasma membrane of our egg cell . it 's started to bind to the plasma membrane , the acrosome is gone , i 'll erase that here . it 's done its job . the cortical granules have been released , and they 're preventing other sperm from getting in . and we start to actually fuse our plasma membranes of our sperm cell and our egg cell . and that allows for this entire structure to come in . all of the genetic material here within the , all of the genetic material within the nucleus of the sperm cell can start to come out and get released here into the egg . and once we have fusion of genetic material , that is fertilization . so just to recap , we 'll go back to look at our close-up of our sperm . we can see that it 's a very mobile structure evolved basically to get genetic material from the male to the female egg cell . it 's got a tail that propulses it , it 's got mitochondria that feed it energy , it 's got a head with a payload of nuclear material and an acrosome warhead on the tip . the egg cell is a giant cell by comparison . it 's got a specialized layer of glycoproteins on the outside that have a bunch of specialized features and then a bunch of cytoplasm , including mitochondria . and then the process of egg meeting sperm itself is called fertilization . sperm binds to the zona pellucida , the glycoproteins , you have an acrosomal reaction , and then a cortical reaction prevents more than one sperm getting in . and then material , the genetic material of the sperm is transferred . now you 'll notice here that i drew the genetic material from the nucleus coming in . now some of you may be wondering , `` well do n't mitochondria have genetic material as well ? '' well , that 's true . mitochondria do have mitochondrial dna . and potentially , some of these mitochondria can get sucked in during that genetic transfer process as well . but remember , our egg cell had 100 to 200 thousand mitochondrial copies , and our sperm cell only had 75 to 100 . now there 's a little bit of debate , but in the end the male contributes essentially no mitochondria to the zygote that 's formed after the egg and sperm fuse . now , it could be that some of those mitochondria actually do make their way in and then are degraded . we 're not really sure . but given just the numbers , statistically with one to two hundred thousand versus only 75 to 100 , nearly all of the genetic material from the mitochondria is gon na be from the mother anyway .
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it 's got a tail that propulses it , it 's got mitochondria that feed it energy , it 's got a head with a payload of nuclear material and an acrosome warhead on the tip . the egg cell is a giant cell by comparison . it 's got a specialized layer of glycoproteins on the outside that have a bunch of specialized features and then a bunch of cytoplasm , including mitochondria .
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why would n't the egg cell always be visible if it is .1 mm in size and .1 mm is easy to see ?
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organisms that reproduce sexually have got to get their genes together somehow . to do this , they package their genetic material into specialized cells called sex cells . this is the sperm cell . it 's the sex cell of the male . the sole purpose of the sperm , the entire reason for its existence , is to transfer the male 's genetic material into the female sex cell or the egg . so the sperm cell is packed with features that allow it to fulfill its job . it 's basically a little torpedo . you can see , just like a torpedo , it has a pointed head which allows it to travel in the forward direction . at the back end it has the tail , and the tail is just a flagellum , and as the flagellum spins it acts like a little propeller . and then it has a middle section . now within that middle section , wrapped around the base of the flagellar tail , are all of these little organelles called mitochondria . you can see i 'm drawing these mitochondria wrapped around the flagellar base here . and mitochondria are organelles that are responsible for giving energy to a cell . and the sperm cell has a whole bunch packed right into the base of the flagellum here . probably 75 to 100 , and they 're quite large mitochondria . in fact , these mitochondria are often fused together to create big organelles . and the reason is because in order to propel the sperm torpedo towards the egg , it needs a lot of energy . and that all comes from these mitochondria . now the payload of the torpedo is here in the head , and that 's the genetic material , our dna within the nucleus . i 'll draw it kind of all coiled back here . and here 's the nuclear envelope here . and just like any regular torpedo , the sperm torpedo has a warhead right in the front . and that warhead is a little collection of enzymes called the acrosome . and the acrosome is gon na be important later on for fertilization . but that 's pretty much it . there 's a tail at the back to provide propulsion , some mitochondria in the middle section to give energy to the tail , a head which contains the nuclear material , and the acrosome . this is a pretty bare bones cell . it 's designed to move fast and to get to the egg . there are no bells and whistles here . now that 's in contrast to the egg cell . now the first thing you 'll notice is that the egg cell is round , unlike the torpedo shape of the sperm cell . this is not a cell that 's made for active mobility . the second thing is that the egg cell is huge compared to the sperm cell . it 's so big , in fact , that it 's almost visible . in fact , sometimes it is visible to the human eye . now compared to the sperm cell , which i 'll draw in here , the egg cell is about 10,000 times more massive . and similar to the sperm cell , the egg cell has its share of genetic material ready to combine during fertilization . you can see it here within the nucleus . and so you may have noticed this thick outer coating on the egg cell here , that 's a very important structure called the zona pellucida . and the zona pellucida is a thick layer of glycoproteins that sit on the outside of the egg . and glycoproteins are basically a protein , i 'll draw a protein here in green , with a whole bunch of branching sugar chains that are coming off of them . and so what this looks like is basically a little tree or a long branching thing that 's growing out of the edge of the egg cell . and there 's a whole bunch of them , and they form this very thick kind of protective layer that the sperm has to get through . and the edge of the egg cell is the actual plasma membrane . and once the sperm can deliver its genetic material beyond that , fertilization has occurred . now there 's a whole bunch of other structures within the egg cytoplasm as well . and remember this thing is huge . and i 'm gon na draw in a few here in green . now what i 'm drawing in are actually more mitochondria . now remember the egg cell had 75 to 100 big mitochondria right at the base of the flagellum to provide energy to drive locomotion . well , the egg cell has mitochondria too . it 's got a lot of other different organelles as well . but the egg cell is so large , it 's got somewhere between 100 and 200 thousand mitochondria present . so keep those mitochondria in mind , we 'll talk about them a little bit later in the next section . so now that you 've met the two major players here , the sperm and the egg , or the male and female sex cells respectively , we can talk about what happens when they meet . and that process is called fertilization . so we 'll go ahead and label our egg down here . and we 'll put a quick label on this as well . this is the zona pellucida that we talked about earlier . so we 'll draw the sperm here coming in to meet the egg . we 'll draw its tail . we 'll draw its middle section here . and we 'll draw its torpedo-like head here . get rid of all this zona pellucida glycoprotein in the middle here . now here are the mitochondria in the middle section here , and we have the genetic material payload of our sperm torpedo here in the back , and our acrosome here in the front . now the first thing that happens during fertilization is that the sperm comes into contact with the zona pellucida . and the zona pellucida actually binds to the outside of the sperm , and that 's called sperm binding . and it 's step number one . now what happens when the sperm gets bound to the zona pellucida is that that sets up a reaction called the acrosomal reaction . so step number two is called the acrosome reaction . and that little warhead tip of the sperm torpedo gets released , and so we have all of the acrosomal enzymes that were sitting in the head that just kind of leak out into that zona pellucida . and as those enzymes leak out , they actually start to digest away the zona pellucida . here you can see i 'm kind of eating away here at those glycoprotein , and that allows the sperm head to dive in deeper towards our plasma membrane . now as the sperm gets closer to the plasma membrane of the egg , and it comes in contact right here , it starts up a process of binding . the two touch and they come together . and as they start together , it causes another reaction , and that third reaction is called cortical reaction . and what i have n't drawn here is another structure in the egg , and those structures are right underneath the plasma membrane , and they just sit there waiting . and they wait and their entire job is to wait for a sperm to bind . and as soon as a single sperm binds , they get ejected out into that zone pellucida as well . just like the acrosomal enzymes , these enzymes that are contained within the cortical granules also start eating away at the zona pellucida . these enzymes eat away , and they dissolve and chew up these glycoproteins , but specifically they chew up the glycoprotein that allows sperm to bind . so at this point we have a single sperm that 's bound , set off the cortical reaction , and these cortical granules are released that chew up all the other places that more sperm can bind . so as our other sperm torpedoes are coming in , they 're just bouncing off . they hit the glycoproteins , but the one that they need to bind to is n't there because it 's all been chewed up and degraded by these cortical granules . so that 's actually called a block to polyspermy . now that 's a very important concept . polyspermy is a term that just means multiple sperm . and what we do n't want is for more than one sperm to inject its nuclear material , its dna into this egg . what you 'd end up with is an egg with a single contribution from mom and then one or two or three or 100 contributions or genetic material from dad . and that would never work , you 'd end up with all sorts of problems as the egg started to divide . occasionally , that does happen , and it can result in a zygote that fails . but for the most part , as these cortical granules dissolve away all the sperm binding glycoproteins of the zona pellucida , other sperm just ca n't get in and they bounce off as they arrive . so now we have a sperm that 's made its way all the way to the plasma membrane of our egg cell . it 's started to bind to the plasma membrane , the acrosome is gone , i 'll erase that here . it 's done its job . the cortical granules have been released , and they 're preventing other sperm from getting in . and we start to actually fuse our plasma membranes of our sperm cell and our egg cell . and that allows for this entire structure to come in . all of the genetic material here within the , all of the genetic material within the nucleus of the sperm cell can start to come out and get released here into the egg . and once we have fusion of genetic material , that is fertilization . so just to recap , we 'll go back to look at our close-up of our sperm . we can see that it 's a very mobile structure evolved basically to get genetic material from the male to the female egg cell . it 's got a tail that propulses it , it 's got mitochondria that feed it energy , it 's got a head with a payload of nuclear material and an acrosome warhead on the tip . the egg cell is a giant cell by comparison . it 's got a specialized layer of glycoproteins on the outside that have a bunch of specialized features and then a bunch of cytoplasm , including mitochondria . and then the process of egg meeting sperm itself is called fertilization . sperm binds to the zona pellucida , the glycoproteins , you have an acrosomal reaction , and then a cortical reaction prevents more than one sperm getting in . and then material , the genetic material of the sperm is transferred . now you 'll notice here that i drew the genetic material from the nucleus coming in . now some of you may be wondering , `` well do n't mitochondria have genetic material as well ? '' well , that 's true . mitochondria do have mitochondrial dna . and potentially , some of these mitochondria can get sucked in during that genetic transfer process as well . but remember , our egg cell had 100 to 200 thousand mitochondrial copies , and our sperm cell only had 75 to 100 . now there 's a little bit of debate , but in the end the male contributes essentially no mitochondria to the zygote that 's formed after the egg and sperm fuse . now , it could be that some of those mitochondria actually do make their way in and then are degraded . we 're not really sure . but given just the numbers , statistically with one to two hundred thousand versus only 75 to 100 , nearly all of the genetic material from the mitochondria is gon na be from the mother anyway .
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and glycoproteins are basically a protein , i 'll draw a protein here in green , with a whole bunch of branching sugar chains that are coming off of them . and so what this looks like is basically a little tree or a long branching thing that 's growing out of the edge of the egg cell . and there 's a whole bunch of them , and they form this very thick kind of protective layer that the sperm has to get through .
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how long do sperms live ?
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organisms that reproduce sexually have got to get their genes together somehow . to do this , they package their genetic material into specialized cells called sex cells . this is the sperm cell . it 's the sex cell of the male . the sole purpose of the sperm , the entire reason for its existence , is to transfer the male 's genetic material into the female sex cell or the egg . so the sperm cell is packed with features that allow it to fulfill its job . it 's basically a little torpedo . you can see , just like a torpedo , it has a pointed head which allows it to travel in the forward direction . at the back end it has the tail , and the tail is just a flagellum , and as the flagellum spins it acts like a little propeller . and then it has a middle section . now within that middle section , wrapped around the base of the flagellar tail , are all of these little organelles called mitochondria . you can see i 'm drawing these mitochondria wrapped around the flagellar base here . and mitochondria are organelles that are responsible for giving energy to a cell . and the sperm cell has a whole bunch packed right into the base of the flagellum here . probably 75 to 100 , and they 're quite large mitochondria . in fact , these mitochondria are often fused together to create big organelles . and the reason is because in order to propel the sperm torpedo towards the egg , it needs a lot of energy . and that all comes from these mitochondria . now the payload of the torpedo is here in the head , and that 's the genetic material , our dna within the nucleus . i 'll draw it kind of all coiled back here . and here 's the nuclear envelope here . and just like any regular torpedo , the sperm torpedo has a warhead right in the front . and that warhead is a little collection of enzymes called the acrosome . and the acrosome is gon na be important later on for fertilization . but that 's pretty much it . there 's a tail at the back to provide propulsion , some mitochondria in the middle section to give energy to the tail , a head which contains the nuclear material , and the acrosome . this is a pretty bare bones cell . it 's designed to move fast and to get to the egg . there are no bells and whistles here . now that 's in contrast to the egg cell . now the first thing you 'll notice is that the egg cell is round , unlike the torpedo shape of the sperm cell . this is not a cell that 's made for active mobility . the second thing is that the egg cell is huge compared to the sperm cell . it 's so big , in fact , that it 's almost visible . in fact , sometimes it is visible to the human eye . now compared to the sperm cell , which i 'll draw in here , the egg cell is about 10,000 times more massive . and similar to the sperm cell , the egg cell has its share of genetic material ready to combine during fertilization . you can see it here within the nucleus . and so you may have noticed this thick outer coating on the egg cell here , that 's a very important structure called the zona pellucida . and the zona pellucida is a thick layer of glycoproteins that sit on the outside of the egg . and glycoproteins are basically a protein , i 'll draw a protein here in green , with a whole bunch of branching sugar chains that are coming off of them . and so what this looks like is basically a little tree or a long branching thing that 's growing out of the edge of the egg cell . and there 's a whole bunch of them , and they form this very thick kind of protective layer that the sperm has to get through . and the edge of the egg cell is the actual plasma membrane . and once the sperm can deliver its genetic material beyond that , fertilization has occurred . now there 's a whole bunch of other structures within the egg cytoplasm as well . and remember this thing is huge . and i 'm gon na draw in a few here in green . now what i 'm drawing in are actually more mitochondria . now remember the egg cell had 75 to 100 big mitochondria right at the base of the flagellum to provide energy to drive locomotion . well , the egg cell has mitochondria too . it 's got a lot of other different organelles as well . but the egg cell is so large , it 's got somewhere between 100 and 200 thousand mitochondria present . so keep those mitochondria in mind , we 'll talk about them a little bit later in the next section . so now that you 've met the two major players here , the sperm and the egg , or the male and female sex cells respectively , we can talk about what happens when they meet . and that process is called fertilization . so we 'll go ahead and label our egg down here . and we 'll put a quick label on this as well . this is the zona pellucida that we talked about earlier . so we 'll draw the sperm here coming in to meet the egg . we 'll draw its tail . we 'll draw its middle section here . and we 'll draw its torpedo-like head here . get rid of all this zona pellucida glycoprotein in the middle here . now here are the mitochondria in the middle section here , and we have the genetic material payload of our sperm torpedo here in the back , and our acrosome here in the front . now the first thing that happens during fertilization is that the sperm comes into contact with the zona pellucida . and the zona pellucida actually binds to the outside of the sperm , and that 's called sperm binding . and it 's step number one . now what happens when the sperm gets bound to the zona pellucida is that that sets up a reaction called the acrosomal reaction . so step number two is called the acrosome reaction . and that little warhead tip of the sperm torpedo gets released , and so we have all of the acrosomal enzymes that were sitting in the head that just kind of leak out into that zona pellucida . and as those enzymes leak out , they actually start to digest away the zona pellucida . here you can see i 'm kind of eating away here at those glycoprotein , and that allows the sperm head to dive in deeper towards our plasma membrane . now as the sperm gets closer to the plasma membrane of the egg , and it comes in contact right here , it starts up a process of binding . the two touch and they come together . and as they start together , it causes another reaction , and that third reaction is called cortical reaction . and what i have n't drawn here is another structure in the egg , and those structures are right underneath the plasma membrane , and they just sit there waiting . and they wait and their entire job is to wait for a sperm to bind . and as soon as a single sperm binds , they get ejected out into that zone pellucida as well . just like the acrosomal enzymes , these enzymes that are contained within the cortical granules also start eating away at the zona pellucida . these enzymes eat away , and they dissolve and chew up these glycoproteins , but specifically they chew up the glycoprotein that allows sperm to bind . so at this point we have a single sperm that 's bound , set off the cortical reaction , and these cortical granules are released that chew up all the other places that more sperm can bind . so as our other sperm torpedoes are coming in , they 're just bouncing off . they hit the glycoproteins , but the one that they need to bind to is n't there because it 's all been chewed up and degraded by these cortical granules . so that 's actually called a block to polyspermy . now that 's a very important concept . polyspermy is a term that just means multiple sperm . and what we do n't want is for more than one sperm to inject its nuclear material , its dna into this egg . what you 'd end up with is an egg with a single contribution from mom and then one or two or three or 100 contributions or genetic material from dad . and that would never work , you 'd end up with all sorts of problems as the egg started to divide . occasionally , that does happen , and it can result in a zygote that fails . but for the most part , as these cortical granules dissolve away all the sperm binding glycoproteins of the zona pellucida , other sperm just ca n't get in and they bounce off as they arrive . so now we have a sperm that 's made its way all the way to the plasma membrane of our egg cell . it 's started to bind to the plasma membrane , the acrosome is gone , i 'll erase that here . it 's done its job . the cortical granules have been released , and they 're preventing other sperm from getting in . and we start to actually fuse our plasma membranes of our sperm cell and our egg cell . and that allows for this entire structure to come in . all of the genetic material here within the , all of the genetic material within the nucleus of the sperm cell can start to come out and get released here into the egg . and once we have fusion of genetic material , that is fertilization . so just to recap , we 'll go back to look at our close-up of our sperm . we can see that it 's a very mobile structure evolved basically to get genetic material from the male to the female egg cell . it 's got a tail that propulses it , it 's got mitochondria that feed it energy , it 's got a head with a payload of nuclear material and an acrosome warhead on the tip . the egg cell is a giant cell by comparison . it 's got a specialized layer of glycoproteins on the outside that have a bunch of specialized features and then a bunch of cytoplasm , including mitochondria . and then the process of egg meeting sperm itself is called fertilization . sperm binds to the zona pellucida , the glycoproteins , you have an acrosomal reaction , and then a cortical reaction prevents more than one sperm getting in . and then material , the genetic material of the sperm is transferred . now you 'll notice here that i drew the genetic material from the nucleus coming in . now some of you may be wondering , `` well do n't mitochondria have genetic material as well ? '' well , that 's true . mitochondria do have mitochondrial dna . and potentially , some of these mitochondria can get sucked in during that genetic transfer process as well . but remember , our egg cell had 100 to 200 thousand mitochondrial copies , and our sperm cell only had 75 to 100 . now there 's a little bit of debate , but in the end the male contributes essentially no mitochondria to the zygote that 's formed after the egg and sperm fuse . now , it could be that some of those mitochondria actually do make their way in and then are degraded . we 're not really sure . but given just the numbers , statistically with one to two hundred thousand versus only 75 to 100 , nearly all of the genetic material from the mitochondria is gon na be from the mother anyway .
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and we 'll put a quick label on this as well . this is the zona pellucida that we talked about earlier . so we 'll draw the sperm here coming in to meet the egg .
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if the zona pellucida is the glycoproteins then what is considered the corona radiata ?
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organisms that reproduce sexually have got to get their genes together somehow . to do this , they package their genetic material into specialized cells called sex cells . this is the sperm cell . it 's the sex cell of the male . the sole purpose of the sperm , the entire reason for its existence , is to transfer the male 's genetic material into the female sex cell or the egg . so the sperm cell is packed with features that allow it to fulfill its job . it 's basically a little torpedo . you can see , just like a torpedo , it has a pointed head which allows it to travel in the forward direction . at the back end it has the tail , and the tail is just a flagellum , and as the flagellum spins it acts like a little propeller . and then it has a middle section . now within that middle section , wrapped around the base of the flagellar tail , are all of these little organelles called mitochondria . you can see i 'm drawing these mitochondria wrapped around the flagellar base here . and mitochondria are organelles that are responsible for giving energy to a cell . and the sperm cell has a whole bunch packed right into the base of the flagellum here . probably 75 to 100 , and they 're quite large mitochondria . in fact , these mitochondria are often fused together to create big organelles . and the reason is because in order to propel the sperm torpedo towards the egg , it needs a lot of energy . and that all comes from these mitochondria . now the payload of the torpedo is here in the head , and that 's the genetic material , our dna within the nucleus . i 'll draw it kind of all coiled back here . and here 's the nuclear envelope here . and just like any regular torpedo , the sperm torpedo has a warhead right in the front . and that warhead is a little collection of enzymes called the acrosome . and the acrosome is gon na be important later on for fertilization . but that 's pretty much it . there 's a tail at the back to provide propulsion , some mitochondria in the middle section to give energy to the tail , a head which contains the nuclear material , and the acrosome . this is a pretty bare bones cell . it 's designed to move fast and to get to the egg . there are no bells and whistles here . now that 's in contrast to the egg cell . now the first thing you 'll notice is that the egg cell is round , unlike the torpedo shape of the sperm cell . this is not a cell that 's made for active mobility . the second thing is that the egg cell is huge compared to the sperm cell . it 's so big , in fact , that it 's almost visible . in fact , sometimes it is visible to the human eye . now compared to the sperm cell , which i 'll draw in here , the egg cell is about 10,000 times more massive . and similar to the sperm cell , the egg cell has its share of genetic material ready to combine during fertilization . you can see it here within the nucleus . and so you may have noticed this thick outer coating on the egg cell here , that 's a very important structure called the zona pellucida . and the zona pellucida is a thick layer of glycoproteins that sit on the outside of the egg . and glycoproteins are basically a protein , i 'll draw a protein here in green , with a whole bunch of branching sugar chains that are coming off of them . and so what this looks like is basically a little tree or a long branching thing that 's growing out of the edge of the egg cell . and there 's a whole bunch of them , and they form this very thick kind of protective layer that the sperm has to get through . and the edge of the egg cell is the actual plasma membrane . and once the sperm can deliver its genetic material beyond that , fertilization has occurred . now there 's a whole bunch of other structures within the egg cytoplasm as well . and remember this thing is huge . and i 'm gon na draw in a few here in green . now what i 'm drawing in are actually more mitochondria . now remember the egg cell had 75 to 100 big mitochondria right at the base of the flagellum to provide energy to drive locomotion . well , the egg cell has mitochondria too . it 's got a lot of other different organelles as well . but the egg cell is so large , it 's got somewhere between 100 and 200 thousand mitochondria present . so keep those mitochondria in mind , we 'll talk about them a little bit later in the next section . so now that you 've met the two major players here , the sperm and the egg , or the male and female sex cells respectively , we can talk about what happens when they meet . and that process is called fertilization . so we 'll go ahead and label our egg down here . and we 'll put a quick label on this as well . this is the zona pellucida that we talked about earlier . so we 'll draw the sperm here coming in to meet the egg . we 'll draw its tail . we 'll draw its middle section here . and we 'll draw its torpedo-like head here . get rid of all this zona pellucida glycoprotein in the middle here . now here are the mitochondria in the middle section here , and we have the genetic material payload of our sperm torpedo here in the back , and our acrosome here in the front . now the first thing that happens during fertilization is that the sperm comes into contact with the zona pellucida . and the zona pellucida actually binds to the outside of the sperm , and that 's called sperm binding . and it 's step number one . now what happens when the sperm gets bound to the zona pellucida is that that sets up a reaction called the acrosomal reaction . so step number two is called the acrosome reaction . and that little warhead tip of the sperm torpedo gets released , and so we have all of the acrosomal enzymes that were sitting in the head that just kind of leak out into that zona pellucida . and as those enzymes leak out , they actually start to digest away the zona pellucida . here you can see i 'm kind of eating away here at those glycoprotein , and that allows the sperm head to dive in deeper towards our plasma membrane . now as the sperm gets closer to the plasma membrane of the egg , and it comes in contact right here , it starts up a process of binding . the two touch and they come together . and as they start together , it causes another reaction , and that third reaction is called cortical reaction . and what i have n't drawn here is another structure in the egg , and those structures are right underneath the plasma membrane , and they just sit there waiting . and they wait and their entire job is to wait for a sperm to bind . and as soon as a single sperm binds , they get ejected out into that zone pellucida as well . just like the acrosomal enzymes , these enzymes that are contained within the cortical granules also start eating away at the zona pellucida . these enzymes eat away , and they dissolve and chew up these glycoproteins , but specifically they chew up the glycoprotein that allows sperm to bind . so at this point we have a single sperm that 's bound , set off the cortical reaction , and these cortical granules are released that chew up all the other places that more sperm can bind . so as our other sperm torpedoes are coming in , they 're just bouncing off . they hit the glycoproteins , but the one that they need to bind to is n't there because it 's all been chewed up and degraded by these cortical granules . so that 's actually called a block to polyspermy . now that 's a very important concept . polyspermy is a term that just means multiple sperm . and what we do n't want is for more than one sperm to inject its nuclear material , its dna into this egg . what you 'd end up with is an egg with a single contribution from mom and then one or two or three or 100 contributions or genetic material from dad . and that would never work , you 'd end up with all sorts of problems as the egg started to divide . occasionally , that does happen , and it can result in a zygote that fails . but for the most part , as these cortical granules dissolve away all the sperm binding glycoproteins of the zona pellucida , other sperm just ca n't get in and they bounce off as they arrive . so now we have a sperm that 's made its way all the way to the plasma membrane of our egg cell . it 's started to bind to the plasma membrane , the acrosome is gone , i 'll erase that here . it 's done its job . the cortical granules have been released , and they 're preventing other sperm from getting in . and we start to actually fuse our plasma membranes of our sperm cell and our egg cell . and that allows for this entire structure to come in . all of the genetic material here within the , all of the genetic material within the nucleus of the sperm cell can start to come out and get released here into the egg . and once we have fusion of genetic material , that is fertilization . so just to recap , we 'll go back to look at our close-up of our sperm . we can see that it 's a very mobile structure evolved basically to get genetic material from the male to the female egg cell . it 's got a tail that propulses it , it 's got mitochondria that feed it energy , it 's got a head with a payload of nuclear material and an acrosome warhead on the tip . the egg cell is a giant cell by comparison . it 's got a specialized layer of glycoproteins on the outside that have a bunch of specialized features and then a bunch of cytoplasm , including mitochondria . and then the process of egg meeting sperm itself is called fertilization . sperm binds to the zona pellucida , the glycoproteins , you have an acrosomal reaction , and then a cortical reaction prevents more than one sperm getting in . and then material , the genetic material of the sperm is transferred . now you 'll notice here that i drew the genetic material from the nucleus coming in . now some of you may be wondering , `` well do n't mitochondria have genetic material as well ? '' well , that 's true . mitochondria do have mitochondrial dna . and potentially , some of these mitochondria can get sucked in during that genetic transfer process as well . but remember , our egg cell had 100 to 200 thousand mitochondrial copies , and our sperm cell only had 75 to 100 . now there 's a little bit of debate , but in the end the male contributes essentially no mitochondria to the zygote that 's formed after the egg and sperm fuse . now , it could be that some of those mitochondria actually do make their way in and then are degraded . we 're not really sure . but given just the numbers , statistically with one to two hundred thousand versus only 75 to 100 , nearly all of the genetic material from the mitochondria is gon na be from the mother anyway .
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to do this , they package their genetic material into specialized cells called sex cells . this is the sperm cell . it 's the sex cell of the male .
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what happens if two sperm bind at the same time ?
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organisms that reproduce sexually have got to get their genes together somehow . to do this , they package their genetic material into specialized cells called sex cells . this is the sperm cell . it 's the sex cell of the male . the sole purpose of the sperm , the entire reason for its existence , is to transfer the male 's genetic material into the female sex cell or the egg . so the sperm cell is packed with features that allow it to fulfill its job . it 's basically a little torpedo . you can see , just like a torpedo , it has a pointed head which allows it to travel in the forward direction . at the back end it has the tail , and the tail is just a flagellum , and as the flagellum spins it acts like a little propeller . and then it has a middle section . now within that middle section , wrapped around the base of the flagellar tail , are all of these little organelles called mitochondria . you can see i 'm drawing these mitochondria wrapped around the flagellar base here . and mitochondria are organelles that are responsible for giving energy to a cell . and the sperm cell has a whole bunch packed right into the base of the flagellum here . probably 75 to 100 , and they 're quite large mitochondria . in fact , these mitochondria are often fused together to create big organelles . and the reason is because in order to propel the sperm torpedo towards the egg , it needs a lot of energy . and that all comes from these mitochondria . now the payload of the torpedo is here in the head , and that 's the genetic material , our dna within the nucleus . i 'll draw it kind of all coiled back here . and here 's the nuclear envelope here . and just like any regular torpedo , the sperm torpedo has a warhead right in the front . and that warhead is a little collection of enzymes called the acrosome . and the acrosome is gon na be important later on for fertilization . but that 's pretty much it . there 's a tail at the back to provide propulsion , some mitochondria in the middle section to give energy to the tail , a head which contains the nuclear material , and the acrosome . this is a pretty bare bones cell . it 's designed to move fast and to get to the egg . there are no bells and whistles here . now that 's in contrast to the egg cell . now the first thing you 'll notice is that the egg cell is round , unlike the torpedo shape of the sperm cell . this is not a cell that 's made for active mobility . the second thing is that the egg cell is huge compared to the sperm cell . it 's so big , in fact , that it 's almost visible . in fact , sometimes it is visible to the human eye . now compared to the sperm cell , which i 'll draw in here , the egg cell is about 10,000 times more massive . and similar to the sperm cell , the egg cell has its share of genetic material ready to combine during fertilization . you can see it here within the nucleus . and so you may have noticed this thick outer coating on the egg cell here , that 's a very important structure called the zona pellucida . and the zona pellucida is a thick layer of glycoproteins that sit on the outside of the egg . and glycoproteins are basically a protein , i 'll draw a protein here in green , with a whole bunch of branching sugar chains that are coming off of them . and so what this looks like is basically a little tree or a long branching thing that 's growing out of the edge of the egg cell . and there 's a whole bunch of them , and they form this very thick kind of protective layer that the sperm has to get through . and the edge of the egg cell is the actual plasma membrane . and once the sperm can deliver its genetic material beyond that , fertilization has occurred . now there 's a whole bunch of other structures within the egg cytoplasm as well . and remember this thing is huge . and i 'm gon na draw in a few here in green . now what i 'm drawing in are actually more mitochondria . now remember the egg cell had 75 to 100 big mitochondria right at the base of the flagellum to provide energy to drive locomotion . well , the egg cell has mitochondria too . it 's got a lot of other different organelles as well . but the egg cell is so large , it 's got somewhere between 100 and 200 thousand mitochondria present . so keep those mitochondria in mind , we 'll talk about them a little bit later in the next section . so now that you 've met the two major players here , the sperm and the egg , or the male and female sex cells respectively , we can talk about what happens when they meet . and that process is called fertilization . so we 'll go ahead and label our egg down here . and we 'll put a quick label on this as well . this is the zona pellucida that we talked about earlier . so we 'll draw the sperm here coming in to meet the egg . we 'll draw its tail . we 'll draw its middle section here . and we 'll draw its torpedo-like head here . get rid of all this zona pellucida glycoprotein in the middle here . now here are the mitochondria in the middle section here , and we have the genetic material payload of our sperm torpedo here in the back , and our acrosome here in the front . now the first thing that happens during fertilization is that the sperm comes into contact with the zona pellucida . and the zona pellucida actually binds to the outside of the sperm , and that 's called sperm binding . and it 's step number one . now what happens when the sperm gets bound to the zona pellucida is that that sets up a reaction called the acrosomal reaction . so step number two is called the acrosome reaction . and that little warhead tip of the sperm torpedo gets released , and so we have all of the acrosomal enzymes that were sitting in the head that just kind of leak out into that zona pellucida . and as those enzymes leak out , they actually start to digest away the zona pellucida . here you can see i 'm kind of eating away here at those glycoprotein , and that allows the sperm head to dive in deeper towards our plasma membrane . now as the sperm gets closer to the plasma membrane of the egg , and it comes in contact right here , it starts up a process of binding . the two touch and they come together . and as they start together , it causes another reaction , and that third reaction is called cortical reaction . and what i have n't drawn here is another structure in the egg , and those structures are right underneath the plasma membrane , and they just sit there waiting . and they wait and their entire job is to wait for a sperm to bind . and as soon as a single sperm binds , they get ejected out into that zone pellucida as well . just like the acrosomal enzymes , these enzymes that are contained within the cortical granules also start eating away at the zona pellucida . these enzymes eat away , and they dissolve and chew up these glycoproteins , but specifically they chew up the glycoprotein that allows sperm to bind . so at this point we have a single sperm that 's bound , set off the cortical reaction , and these cortical granules are released that chew up all the other places that more sperm can bind . so as our other sperm torpedoes are coming in , they 're just bouncing off . they hit the glycoproteins , but the one that they need to bind to is n't there because it 's all been chewed up and degraded by these cortical granules . so that 's actually called a block to polyspermy . now that 's a very important concept . polyspermy is a term that just means multiple sperm . and what we do n't want is for more than one sperm to inject its nuclear material , its dna into this egg . what you 'd end up with is an egg with a single contribution from mom and then one or two or three or 100 contributions or genetic material from dad . and that would never work , you 'd end up with all sorts of problems as the egg started to divide . occasionally , that does happen , and it can result in a zygote that fails . but for the most part , as these cortical granules dissolve away all the sperm binding glycoproteins of the zona pellucida , other sperm just ca n't get in and they bounce off as they arrive . so now we have a sperm that 's made its way all the way to the plasma membrane of our egg cell . it 's started to bind to the plasma membrane , the acrosome is gone , i 'll erase that here . it 's done its job . the cortical granules have been released , and they 're preventing other sperm from getting in . and we start to actually fuse our plasma membranes of our sperm cell and our egg cell . and that allows for this entire structure to come in . all of the genetic material here within the , all of the genetic material within the nucleus of the sperm cell can start to come out and get released here into the egg . and once we have fusion of genetic material , that is fertilization . so just to recap , we 'll go back to look at our close-up of our sperm . we can see that it 's a very mobile structure evolved basically to get genetic material from the male to the female egg cell . it 's got a tail that propulses it , it 's got mitochondria that feed it energy , it 's got a head with a payload of nuclear material and an acrosome warhead on the tip . the egg cell is a giant cell by comparison . it 's got a specialized layer of glycoproteins on the outside that have a bunch of specialized features and then a bunch of cytoplasm , including mitochondria . and then the process of egg meeting sperm itself is called fertilization . sperm binds to the zona pellucida , the glycoproteins , you have an acrosomal reaction , and then a cortical reaction prevents more than one sperm getting in . and then material , the genetic material of the sperm is transferred . now you 'll notice here that i drew the genetic material from the nucleus coming in . now some of you may be wondering , `` well do n't mitochondria have genetic material as well ? '' well , that 's true . mitochondria do have mitochondrial dna . and potentially , some of these mitochondria can get sucked in during that genetic transfer process as well . but remember , our egg cell had 100 to 200 thousand mitochondrial copies , and our sperm cell only had 75 to 100 . now there 's a little bit of debate , but in the end the male contributes essentially no mitochondria to the zygote that 's formed after the egg and sperm fuse . now , it could be that some of those mitochondria actually do make their way in and then are degraded . we 're not really sure . but given just the numbers , statistically with one to two hundred thousand versus only 75 to 100 , nearly all of the genetic material from the mitochondria is gon na be from the mother anyway .
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the two touch and they come together . and as they start together , it causes another reaction , and that third reaction is called cortical reaction . and what i have n't drawn here is another structure in the egg , and those structures are right underneath the plasma membrane , and they just sit there waiting .
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what are the functions of esterase , hyaluronidase and acrosin in arosome reaction ?
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organisms that reproduce sexually have got to get their genes together somehow . to do this , they package their genetic material into specialized cells called sex cells . this is the sperm cell . it 's the sex cell of the male . the sole purpose of the sperm , the entire reason for its existence , is to transfer the male 's genetic material into the female sex cell or the egg . so the sperm cell is packed with features that allow it to fulfill its job . it 's basically a little torpedo . you can see , just like a torpedo , it has a pointed head which allows it to travel in the forward direction . at the back end it has the tail , and the tail is just a flagellum , and as the flagellum spins it acts like a little propeller . and then it has a middle section . now within that middle section , wrapped around the base of the flagellar tail , are all of these little organelles called mitochondria . you can see i 'm drawing these mitochondria wrapped around the flagellar base here . and mitochondria are organelles that are responsible for giving energy to a cell . and the sperm cell has a whole bunch packed right into the base of the flagellum here . probably 75 to 100 , and they 're quite large mitochondria . in fact , these mitochondria are often fused together to create big organelles . and the reason is because in order to propel the sperm torpedo towards the egg , it needs a lot of energy . and that all comes from these mitochondria . now the payload of the torpedo is here in the head , and that 's the genetic material , our dna within the nucleus . i 'll draw it kind of all coiled back here . and here 's the nuclear envelope here . and just like any regular torpedo , the sperm torpedo has a warhead right in the front . and that warhead is a little collection of enzymes called the acrosome . and the acrosome is gon na be important later on for fertilization . but that 's pretty much it . there 's a tail at the back to provide propulsion , some mitochondria in the middle section to give energy to the tail , a head which contains the nuclear material , and the acrosome . this is a pretty bare bones cell . it 's designed to move fast and to get to the egg . there are no bells and whistles here . now that 's in contrast to the egg cell . now the first thing you 'll notice is that the egg cell is round , unlike the torpedo shape of the sperm cell . this is not a cell that 's made for active mobility . the second thing is that the egg cell is huge compared to the sperm cell . it 's so big , in fact , that it 's almost visible . in fact , sometimes it is visible to the human eye . now compared to the sperm cell , which i 'll draw in here , the egg cell is about 10,000 times more massive . and similar to the sperm cell , the egg cell has its share of genetic material ready to combine during fertilization . you can see it here within the nucleus . and so you may have noticed this thick outer coating on the egg cell here , that 's a very important structure called the zona pellucida . and the zona pellucida is a thick layer of glycoproteins that sit on the outside of the egg . and glycoproteins are basically a protein , i 'll draw a protein here in green , with a whole bunch of branching sugar chains that are coming off of them . and so what this looks like is basically a little tree or a long branching thing that 's growing out of the edge of the egg cell . and there 's a whole bunch of them , and they form this very thick kind of protective layer that the sperm has to get through . and the edge of the egg cell is the actual plasma membrane . and once the sperm can deliver its genetic material beyond that , fertilization has occurred . now there 's a whole bunch of other structures within the egg cytoplasm as well . and remember this thing is huge . and i 'm gon na draw in a few here in green . now what i 'm drawing in are actually more mitochondria . now remember the egg cell had 75 to 100 big mitochondria right at the base of the flagellum to provide energy to drive locomotion . well , the egg cell has mitochondria too . it 's got a lot of other different organelles as well . but the egg cell is so large , it 's got somewhere between 100 and 200 thousand mitochondria present . so keep those mitochondria in mind , we 'll talk about them a little bit later in the next section . so now that you 've met the two major players here , the sperm and the egg , or the male and female sex cells respectively , we can talk about what happens when they meet . and that process is called fertilization . so we 'll go ahead and label our egg down here . and we 'll put a quick label on this as well . this is the zona pellucida that we talked about earlier . so we 'll draw the sperm here coming in to meet the egg . we 'll draw its tail . we 'll draw its middle section here . and we 'll draw its torpedo-like head here . get rid of all this zona pellucida glycoprotein in the middle here . now here are the mitochondria in the middle section here , and we have the genetic material payload of our sperm torpedo here in the back , and our acrosome here in the front . now the first thing that happens during fertilization is that the sperm comes into contact with the zona pellucida . and the zona pellucida actually binds to the outside of the sperm , and that 's called sperm binding . and it 's step number one . now what happens when the sperm gets bound to the zona pellucida is that that sets up a reaction called the acrosomal reaction . so step number two is called the acrosome reaction . and that little warhead tip of the sperm torpedo gets released , and so we have all of the acrosomal enzymes that were sitting in the head that just kind of leak out into that zona pellucida . and as those enzymes leak out , they actually start to digest away the zona pellucida . here you can see i 'm kind of eating away here at those glycoprotein , and that allows the sperm head to dive in deeper towards our plasma membrane . now as the sperm gets closer to the plasma membrane of the egg , and it comes in contact right here , it starts up a process of binding . the two touch and they come together . and as they start together , it causes another reaction , and that third reaction is called cortical reaction . and what i have n't drawn here is another structure in the egg , and those structures are right underneath the plasma membrane , and they just sit there waiting . and they wait and their entire job is to wait for a sperm to bind . and as soon as a single sperm binds , they get ejected out into that zone pellucida as well . just like the acrosomal enzymes , these enzymes that are contained within the cortical granules also start eating away at the zona pellucida . these enzymes eat away , and they dissolve and chew up these glycoproteins , but specifically they chew up the glycoprotein that allows sperm to bind . so at this point we have a single sperm that 's bound , set off the cortical reaction , and these cortical granules are released that chew up all the other places that more sperm can bind . so as our other sperm torpedoes are coming in , they 're just bouncing off . they hit the glycoproteins , but the one that they need to bind to is n't there because it 's all been chewed up and degraded by these cortical granules . so that 's actually called a block to polyspermy . now that 's a very important concept . polyspermy is a term that just means multiple sperm . and what we do n't want is for more than one sperm to inject its nuclear material , its dna into this egg . what you 'd end up with is an egg with a single contribution from mom and then one or two or three or 100 contributions or genetic material from dad . and that would never work , you 'd end up with all sorts of problems as the egg started to divide . occasionally , that does happen , and it can result in a zygote that fails . but for the most part , as these cortical granules dissolve away all the sperm binding glycoproteins of the zona pellucida , other sperm just ca n't get in and they bounce off as they arrive . so now we have a sperm that 's made its way all the way to the plasma membrane of our egg cell . it 's started to bind to the plasma membrane , the acrosome is gone , i 'll erase that here . it 's done its job . the cortical granules have been released , and they 're preventing other sperm from getting in . and we start to actually fuse our plasma membranes of our sperm cell and our egg cell . and that allows for this entire structure to come in . all of the genetic material here within the , all of the genetic material within the nucleus of the sperm cell can start to come out and get released here into the egg . and once we have fusion of genetic material , that is fertilization . so just to recap , we 'll go back to look at our close-up of our sperm . we can see that it 's a very mobile structure evolved basically to get genetic material from the male to the female egg cell . it 's got a tail that propulses it , it 's got mitochondria that feed it energy , it 's got a head with a payload of nuclear material and an acrosome warhead on the tip . the egg cell is a giant cell by comparison . it 's got a specialized layer of glycoproteins on the outside that have a bunch of specialized features and then a bunch of cytoplasm , including mitochondria . and then the process of egg meeting sperm itself is called fertilization . sperm binds to the zona pellucida , the glycoproteins , you have an acrosomal reaction , and then a cortical reaction prevents more than one sperm getting in . and then material , the genetic material of the sperm is transferred . now you 'll notice here that i drew the genetic material from the nucleus coming in . now some of you may be wondering , `` well do n't mitochondria have genetic material as well ? '' well , that 's true . mitochondria do have mitochondrial dna . and potentially , some of these mitochondria can get sucked in during that genetic transfer process as well . but remember , our egg cell had 100 to 200 thousand mitochondrial copies , and our sperm cell only had 75 to 100 . now there 's a little bit of debate , but in the end the male contributes essentially no mitochondria to the zygote that 's formed after the egg and sperm fuse . now , it could be that some of those mitochondria actually do make their way in and then are degraded . we 're not really sure . but given just the numbers , statistically with one to two hundred thousand versus only 75 to 100 , nearly all of the genetic material from the mitochondria is gon na be from the mother anyway .
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here you can see i 'm kind of eating away here at those glycoprotein , and that allows the sperm head to dive in deeper towards our plasma membrane . now as the sperm gets closer to the plasma membrane of the egg , and it comes in contact right here , it starts up a process of binding . the two touch and they come together .
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does the egg protects itself from plyspemy , by releasing ca , by doing so changing the depolarization of its outer membrane and therefore , inhibiting the binding process ?
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organisms that reproduce sexually have got to get their genes together somehow . to do this , they package their genetic material into specialized cells called sex cells . this is the sperm cell . it 's the sex cell of the male . the sole purpose of the sperm , the entire reason for its existence , is to transfer the male 's genetic material into the female sex cell or the egg . so the sperm cell is packed with features that allow it to fulfill its job . it 's basically a little torpedo . you can see , just like a torpedo , it has a pointed head which allows it to travel in the forward direction . at the back end it has the tail , and the tail is just a flagellum , and as the flagellum spins it acts like a little propeller . and then it has a middle section . now within that middle section , wrapped around the base of the flagellar tail , are all of these little organelles called mitochondria . you can see i 'm drawing these mitochondria wrapped around the flagellar base here . and mitochondria are organelles that are responsible for giving energy to a cell . and the sperm cell has a whole bunch packed right into the base of the flagellum here . probably 75 to 100 , and they 're quite large mitochondria . in fact , these mitochondria are often fused together to create big organelles . and the reason is because in order to propel the sperm torpedo towards the egg , it needs a lot of energy . and that all comes from these mitochondria . now the payload of the torpedo is here in the head , and that 's the genetic material , our dna within the nucleus . i 'll draw it kind of all coiled back here . and here 's the nuclear envelope here . and just like any regular torpedo , the sperm torpedo has a warhead right in the front . and that warhead is a little collection of enzymes called the acrosome . and the acrosome is gon na be important later on for fertilization . but that 's pretty much it . there 's a tail at the back to provide propulsion , some mitochondria in the middle section to give energy to the tail , a head which contains the nuclear material , and the acrosome . this is a pretty bare bones cell . it 's designed to move fast and to get to the egg . there are no bells and whistles here . now that 's in contrast to the egg cell . now the first thing you 'll notice is that the egg cell is round , unlike the torpedo shape of the sperm cell . this is not a cell that 's made for active mobility . the second thing is that the egg cell is huge compared to the sperm cell . it 's so big , in fact , that it 's almost visible . in fact , sometimes it is visible to the human eye . now compared to the sperm cell , which i 'll draw in here , the egg cell is about 10,000 times more massive . and similar to the sperm cell , the egg cell has its share of genetic material ready to combine during fertilization . you can see it here within the nucleus . and so you may have noticed this thick outer coating on the egg cell here , that 's a very important structure called the zona pellucida . and the zona pellucida is a thick layer of glycoproteins that sit on the outside of the egg . and glycoproteins are basically a protein , i 'll draw a protein here in green , with a whole bunch of branching sugar chains that are coming off of them . and so what this looks like is basically a little tree or a long branching thing that 's growing out of the edge of the egg cell . and there 's a whole bunch of them , and they form this very thick kind of protective layer that the sperm has to get through . and the edge of the egg cell is the actual plasma membrane . and once the sperm can deliver its genetic material beyond that , fertilization has occurred . now there 's a whole bunch of other structures within the egg cytoplasm as well . and remember this thing is huge . and i 'm gon na draw in a few here in green . now what i 'm drawing in are actually more mitochondria . now remember the egg cell had 75 to 100 big mitochondria right at the base of the flagellum to provide energy to drive locomotion . well , the egg cell has mitochondria too . it 's got a lot of other different organelles as well . but the egg cell is so large , it 's got somewhere between 100 and 200 thousand mitochondria present . so keep those mitochondria in mind , we 'll talk about them a little bit later in the next section . so now that you 've met the two major players here , the sperm and the egg , or the male and female sex cells respectively , we can talk about what happens when they meet . and that process is called fertilization . so we 'll go ahead and label our egg down here . and we 'll put a quick label on this as well . this is the zona pellucida that we talked about earlier . so we 'll draw the sperm here coming in to meet the egg . we 'll draw its tail . we 'll draw its middle section here . and we 'll draw its torpedo-like head here . get rid of all this zona pellucida glycoprotein in the middle here . now here are the mitochondria in the middle section here , and we have the genetic material payload of our sperm torpedo here in the back , and our acrosome here in the front . now the first thing that happens during fertilization is that the sperm comes into contact with the zona pellucida . and the zona pellucida actually binds to the outside of the sperm , and that 's called sperm binding . and it 's step number one . now what happens when the sperm gets bound to the zona pellucida is that that sets up a reaction called the acrosomal reaction . so step number two is called the acrosome reaction . and that little warhead tip of the sperm torpedo gets released , and so we have all of the acrosomal enzymes that were sitting in the head that just kind of leak out into that zona pellucida . and as those enzymes leak out , they actually start to digest away the zona pellucida . here you can see i 'm kind of eating away here at those glycoprotein , and that allows the sperm head to dive in deeper towards our plasma membrane . now as the sperm gets closer to the plasma membrane of the egg , and it comes in contact right here , it starts up a process of binding . the two touch and they come together . and as they start together , it causes another reaction , and that third reaction is called cortical reaction . and what i have n't drawn here is another structure in the egg , and those structures are right underneath the plasma membrane , and they just sit there waiting . and they wait and their entire job is to wait for a sperm to bind . and as soon as a single sperm binds , they get ejected out into that zone pellucida as well . just like the acrosomal enzymes , these enzymes that are contained within the cortical granules also start eating away at the zona pellucida . these enzymes eat away , and they dissolve and chew up these glycoproteins , but specifically they chew up the glycoprotein that allows sperm to bind . so at this point we have a single sperm that 's bound , set off the cortical reaction , and these cortical granules are released that chew up all the other places that more sperm can bind . so as our other sperm torpedoes are coming in , they 're just bouncing off . they hit the glycoproteins , but the one that they need to bind to is n't there because it 's all been chewed up and degraded by these cortical granules . so that 's actually called a block to polyspermy . now that 's a very important concept . polyspermy is a term that just means multiple sperm . and what we do n't want is for more than one sperm to inject its nuclear material , its dna into this egg . what you 'd end up with is an egg with a single contribution from mom and then one or two or three or 100 contributions or genetic material from dad . and that would never work , you 'd end up with all sorts of problems as the egg started to divide . occasionally , that does happen , and it can result in a zygote that fails . but for the most part , as these cortical granules dissolve away all the sperm binding glycoproteins of the zona pellucida , other sperm just ca n't get in and they bounce off as they arrive . so now we have a sperm that 's made its way all the way to the plasma membrane of our egg cell . it 's started to bind to the plasma membrane , the acrosome is gone , i 'll erase that here . it 's done its job . the cortical granules have been released , and they 're preventing other sperm from getting in . and we start to actually fuse our plasma membranes of our sperm cell and our egg cell . and that allows for this entire structure to come in . all of the genetic material here within the , all of the genetic material within the nucleus of the sperm cell can start to come out and get released here into the egg . and once we have fusion of genetic material , that is fertilization . so just to recap , we 'll go back to look at our close-up of our sperm . we can see that it 's a very mobile structure evolved basically to get genetic material from the male to the female egg cell . it 's got a tail that propulses it , it 's got mitochondria that feed it energy , it 's got a head with a payload of nuclear material and an acrosome warhead on the tip . the egg cell is a giant cell by comparison . it 's got a specialized layer of glycoproteins on the outside that have a bunch of specialized features and then a bunch of cytoplasm , including mitochondria . and then the process of egg meeting sperm itself is called fertilization . sperm binds to the zona pellucida , the glycoproteins , you have an acrosomal reaction , and then a cortical reaction prevents more than one sperm getting in . and then material , the genetic material of the sperm is transferred . now you 'll notice here that i drew the genetic material from the nucleus coming in . now some of you may be wondering , `` well do n't mitochondria have genetic material as well ? '' well , that 's true . mitochondria do have mitochondrial dna . and potentially , some of these mitochondria can get sucked in during that genetic transfer process as well . but remember , our egg cell had 100 to 200 thousand mitochondrial copies , and our sperm cell only had 75 to 100 . now there 's a little bit of debate , but in the end the male contributes essentially no mitochondria to the zygote that 's formed after the egg and sperm fuse . now , it could be that some of those mitochondria actually do make their way in and then are degraded . we 're not really sure . but given just the numbers , statistically with one to two hundred thousand versus only 75 to 100 , nearly all of the genetic material from the mitochondria is gon na be from the mother anyway .
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occasionally , that does happen , and it can result in a zygote that fails . but for the most part , as these cortical granules dissolve away all the sperm binding glycoproteins of the zona pellucida , other sperm just ca n't get in and they bounce off as they arrive . so now we have a sperm that 's made its way all the way to the plasma membrane of our egg cell .
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or the rule of the ca is that eating up the glycoproteins ?
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organisms that reproduce sexually have got to get their genes together somehow . to do this , they package their genetic material into specialized cells called sex cells . this is the sperm cell . it 's the sex cell of the male . the sole purpose of the sperm , the entire reason for its existence , is to transfer the male 's genetic material into the female sex cell or the egg . so the sperm cell is packed with features that allow it to fulfill its job . it 's basically a little torpedo . you can see , just like a torpedo , it has a pointed head which allows it to travel in the forward direction . at the back end it has the tail , and the tail is just a flagellum , and as the flagellum spins it acts like a little propeller . and then it has a middle section . now within that middle section , wrapped around the base of the flagellar tail , are all of these little organelles called mitochondria . you can see i 'm drawing these mitochondria wrapped around the flagellar base here . and mitochondria are organelles that are responsible for giving energy to a cell . and the sperm cell has a whole bunch packed right into the base of the flagellum here . probably 75 to 100 , and they 're quite large mitochondria . in fact , these mitochondria are often fused together to create big organelles . and the reason is because in order to propel the sperm torpedo towards the egg , it needs a lot of energy . and that all comes from these mitochondria . now the payload of the torpedo is here in the head , and that 's the genetic material , our dna within the nucleus . i 'll draw it kind of all coiled back here . and here 's the nuclear envelope here . and just like any regular torpedo , the sperm torpedo has a warhead right in the front . and that warhead is a little collection of enzymes called the acrosome . and the acrosome is gon na be important later on for fertilization . but that 's pretty much it . there 's a tail at the back to provide propulsion , some mitochondria in the middle section to give energy to the tail , a head which contains the nuclear material , and the acrosome . this is a pretty bare bones cell . it 's designed to move fast and to get to the egg . there are no bells and whistles here . now that 's in contrast to the egg cell . now the first thing you 'll notice is that the egg cell is round , unlike the torpedo shape of the sperm cell . this is not a cell that 's made for active mobility . the second thing is that the egg cell is huge compared to the sperm cell . it 's so big , in fact , that it 's almost visible . in fact , sometimes it is visible to the human eye . now compared to the sperm cell , which i 'll draw in here , the egg cell is about 10,000 times more massive . and similar to the sperm cell , the egg cell has its share of genetic material ready to combine during fertilization . you can see it here within the nucleus . and so you may have noticed this thick outer coating on the egg cell here , that 's a very important structure called the zona pellucida . and the zona pellucida is a thick layer of glycoproteins that sit on the outside of the egg . and glycoproteins are basically a protein , i 'll draw a protein here in green , with a whole bunch of branching sugar chains that are coming off of them . and so what this looks like is basically a little tree or a long branching thing that 's growing out of the edge of the egg cell . and there 's a whole bunch of them , and they form this very thick kind of protective layer that the sperm has to get through . and the edge of the egg cell is the actual plasma membrane . and once the sperm can deliver its genetic material beyond that , fertilization has occurred . now there 's a whole bunch of other structures within the egg cytoplasm as well . and remember this thing is huge . and i 'm gon na draw in a few here in green . now what i 'm drawing in are actually more mitochondria . now remember the egg cell had 75 to 100 big mitochondria right at the base of the flagellum to provide energy to drive locomotion . well , the egg cell has mitochondria too . it 's got a lot of other different organelles as well . but the egg cell is so large , it 's got somewhere between 100 and 200 thousand mitochondria present . so keep those mitochondria in mind , we 'll talk about them a little bit later in the next section . so now that you 've met the two major players here , the sperm and the egg , or the male and female sex cells respectively , we can talk about what happens when they meet . and that process is called fertilization . so we 'll go ahead and label our egg down here . and we 'll put a quick label on this as well . this is the zona pellucida that we talked about earlier . so we 'll draw the sperm here coming in to meet the egg . we 'll draw its tail . we 'll draw its middle section here . and we 'll draw its torpedo-like head here . get rid of all this zona pellucida glycoprotein in the middle here . now here are the mitochondria in the middle section here , and we have the genetic material payload of our sperm torpedo here in the back , and our acrosome here in the front . now the first thing that happens during fertilization is that the sperm comes into contact with the zona pellucida . and the zona pellucida actually binds to the outside of the sperm , and that 's called sperm binding . and it 's step number one . now what happens when the sperm gets bound to the zona pellucida is that that sets up a reaction called the acrosomal reaction . so step number two is called the acrosome reaction . and that little warhead tip of the sperm torpedo gets released , and so we have all of the acrosomal enzymes that were sitting in the head that just kind of leak out into that zona pellucida . and as those enzymes leak out , they actually start to digest away the zona pellucida . here you can see i 'm kind of eating away here at those glycoprotein , and that allows the sperm head to dive in deeper towards our plasma membrane . now as the sperm gets closer to the plasma membrane of the egg , and it comes in contact right here , it starts up a process of binding . the two touch and they come together . and as they start together , it causes another reaction , and that third reaction is called cortical reaction . and what i have n't drawn here is another structure in the egg , and those structures are right underneath the plasma membrane , and they just sit there waiting . and they wait and their entire job is to wait for a sperm to bind . and as soon as a single sperm binds , they get ejected out into that zone pellucida as well . just like the acrosomal enzymes , these enzymes that are contained within the cortical granules also start eating away at the zona pellucida . these enzymes eat away , and they dissolve and chew up these glycoproteins , but specifically they chew up the glycoprotein that allows sperm to bind . so at this point we have a single sperm that 's bound , set off the cortical reaction , and these cortical granules are released that chew up all the other places that more sperm can bind . so as our other sperm torpedoes are coming in , they 're just bouncing off . they hit the glycoproteins , but the one that they need to bind to is n't there because it 's all been chewed up and degraded by these cortical granules . so that 's actually called a block to polyspermy . now that 's a very important concept . polyspermy is a term that just means multiple sperm . and what we do n't want is for more than one sperm to inject its nuclear material , its dna into this egg . what you 'd end up with is an egg with a single contribution from mom and then one or two or three or 100 contributions or genetic material from dad . and that would never work , you 'd end up with all sorts of problems as the egg started to divide . occasionally , that does happen , and it can result in a zygote that fails . but for the most part , as these cortical granules dissolve away all the sperm binding glycoproteins of the zona pellucida , other sperm just ca n't get in and they bounce off as they arrive . so now we have a sperm that 's made its way all the way to the plasma membrane of our egg cell . it 's started to bind to the plasma membrane , the acrosome is gone , i 'll erase that here . it 's done its job . the cortical granules have been released , and they 're preventing other sperm from getting in . and we start to actually fuse our plasma membranes of our sperm cell and our egg cell . and that allows for this entire structure to come in . all of the genetic material here within the , all of the genetic material within the nucleus of the sperm cell can start to come out and get released here into the egg . and once we have fusion of genetic material , that is fertilization . so just to recap , we 'll go back to look at our close-up of our sperm . we can see that it 's a very mobile structure evolved basically to get genetic material from the male to the female egg cell . it 's got a tail that propulses it , it 's got mitochondria that feed it energy , it 's got a head with a payload of nuclear material and an acrosome warhead on the tip . the egg cell is a giant cell by comparison . it 's got a specialized layer of glycoproteins on the outside that have a bunch of specialized features and then a bunch of cytoplasm , including mitochondria . and then the process of egg meeting sperm itself is called fertilization . sperm binds to the zona pellucida , the glycoproteins , you have an acrosomal reaction , and then a cortical reaction prevents more than one sperm getting in . and then material , the genetic material of the sperm is transferred . now you 'll notice here that i drew the genetic material from the nucleus coming in . now some of you may be wondering , `` well do n't mitochondria have genetic material as well ? '' well , that 's true . mitochondria do have mitochondrial dna . and potentially , some of these mitochondria can get sucked in during that genetic transfer process as well . but remember , our egg cell had 100 to 200 thousand mitochondrial copies , and our sperm cell only had 75 to 100 . now there 's a little bit of debate , but in the end the male contributes essentially no mitochondria to the zygote that 's formed after the egg and sperm fuse . now , it could be that some of those mitochondria actually do make their way in and then are degraded . we 're not really sure . but given just the numbers , statistically with one to two hundred thousand versus only 75 to 100 , nearly all of the genetic material from the mitochondria is gon na be from the mother anyway .
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and the zona pellucida actually binds to the outside of the sperm , and that 's called sperm binding . and it 's step number one . now what happens when the sperm gets bound to the zona pellucida is that that sets up a reaction called the acrosomal reaction .
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how many sperms at one ejaculation from the male are released ?
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organisms that reproduce sexually have got to get their genes together somehow . to do this , they package their genetic material into specialized cells called sex cells . this is the sperm cell . it 's the sex cell of the male . the sole purpose of the sperm , the entire reason for its existence , is to transfer the male 's genetic material into the female sex cell or the egg . so the sperm cell is packed with features that allow it to fulfill its job . it 's basically a little torpedo . you can see , just like a torpedo , it has a pointed head which allows it to travel in the forward direction . at the back end it has the tail , and the tail is just a flagellum , and as the flagellum spins it acts like a little propeller . and then it has a middle section . now within that middle section , wrapped around the base of the flagellar tail , are all of these little organelles called mitochondria . you can see i 'm drawing these mitochondria wrapped around the flagellar base here . and mitochondria are organelles that are responsible for giving energy to a cell . and the sperm cell has a whole bunch packed right into the base of the flagellum here . probably 75 to 100 , and they 're quite large mitochondria . in fact , these mitochondria are often fused together to create big organelles . and the reason is because in order to propel the sperm torpedo towards the egg , it needs a lot of energy . and that all comes from these mitochondria . now the payload of the torpedo is here in the head , and that 's the genetic material , our dna within the nucleus . i 'll draw it kind of all coiled back here . and here 's the nuclear envelope here . and just like any regular torpedo , the sperm torpedo has a warhead right in the front . and that warhead is a little collection of enzymes called the acrosome . and the acrosome is gon na be important later on for fertilization . but that 's pretty much it . there 's a tail at the back to provide propulsion , some mitochondria in the middle section to give energy to the tail , a head which contains the nuclear material , and the acrosome . this is a pretty bare bones cell . it 's designed to move fast and to get to the egg . there are no bells and whistles here . now that 's in contrast to the egg cell . now the first thing you 'll notice is that the egg cell is round , unlike the torpedo shape of the sperm cell . this is not a cell that 's made for active mobility . the second thing is that the egg cell is huge compared to the sperm cell . it 's so big , in fact , that it 's almost visible . in fact , sometimes it is visible to the human eye . now compared to the sperm cell , which i 'll draw in here , the egg cell is about 10,000 times more massive . and similar to the sperm cell , the egg cell has its share of genetic material ready to combine during fertilization . you can see it here within the nucleus . and so you may have noticed this thick outer coating on the egg cell here , that 's a very important structure called the zona pellucida . and the zona pellucida is a thick layer of glycoproteins that sit on the outside of the egg . and glycoproteins are basically a protein , i 'll draw a protein here in green , with a whole bunch of branching sugar chains that are coming off of them . and so what this looks like is basically a little tree or a long branching thing that 's growing out of the edge of the egg cell . and there 's a whole bunch of them , and they form this very thick kind of protective layer that the sperm has to get through . and the edge of the egg cell is the actual plasma membrane . and once the sperm can deliver its genetic material beyond that , fertilization has occurred . now there 's a whole bunch of other structures within the egg cytoplasm as well . and remember this thing is huge . and i 'm gon na draw in a few here in green . now what i 'm drawing in are actually more mitochondria . now remember the egg cell had 75 to 100 big mitochondria right at the base of the flagellum to provide energy to drive locomotion . well , the egg cell has mitochondria too . it 's got a lot of other different organelles as well . but the egg cell is so large , it 's got somewhere between 100 and 200 thousand mitochondria present . so keep those mitochondria in mind , we 'll talk about them a little bit later in the next section . so now that you 've met the two major players here , the sperm and the egg , or the male and female sex cells respectively , we can talk about what happens when they meet . and that process is called fertilization . so we 'll go ahead and label our egg down here . and we 'll put a quick label on this as well . this is the zona pellucida that we talked about earlier . so we 'll draw the sperm here coming in to meet the egg . we 'll draw its tail . we 'll draw its middle section here . and we 'll draw its torpedo-like head here . get rid of all this zona pellucida glycoprotein in the middle here . now here are the mitochondria in the middle section here , and we have the genetic material payload of our sperm torpedo here in the back , and our acrosome here in the front . now the first thing that happens during fertilization is that the sperm comes into contact with the zona pellucida . and the zona pellucida actually binds to the outside of the sperm , and that 's called sperm binding . and it 's step number one . now what happens when the sperm gets bound to the zona pellucida is that that sets up a reaction called the acrosomal reaction . so step number two is called the acrosome reaction . and that little warhead tip of the sperm torpedo gets released , and so we have all of the acrosomal enzymes that were sitting in the head that just kind of leak out into that zona pellucida . and as those enzymes leak out , they actually start to digest away the zona pellucida . here you can see i 'm kind of eating away here at those glycoprotein , and that allows the sperm head to dive in deeper towards our plasma membrane . now as the sperm gets closer to the plasma membrane of the egg , and it comes in contact right here , it starts up a process of binding . the two touch and they come together . and as they start together , it causes another reaction , and that third reaction is called cortical reaction . and what i have n't drawn here is another structure in the egg , and those structures are right underneath the plasma membrane , and they just sit there waiting . and they wait and their entire job is to wait for a sperm to bind . and as soon as a single sperm binds , they get ejected out into that zone pellucida as well . just like the acrosomal enzymes , these enzymes that are contained within the cortical granules also start eating away at the zona pellucida . these enzymes eat away , and they dissolve and chew up these glycoproteins , but specifically they chew up the glycoprotein that allows sperm to bind . so at this point we have a single sperm that 's bound , set off the cortical reaction , and these cortical granules are released that chew up all the other places that more sperm can bind . so as our other sperm torpedoes are coming in , they 're just bouncing off . they hit the glycoproteins , but the one that they need to bind to is n't there because it 's all been chewed up and degraded by these cortical granules . so that 's actually called a block to polyspermy . now that 's a very important concept . polyspermy is a term that just means multiple sperm . and what we do n't want is for more than one sperm to inject its nuclear material , its dna into this egg . what you 'd end up with is an egg with a single contribution from mom and then one or two or three or 100 contributions or genetic material from dad . and that would never work , you 'd end up with all sorts of problems as the egg started to divide . occasionally , that does happen , and it can result in a zygote that fails . but for the most part , as these cortical granules dissolve away all the sperm binding glycoproteins of the zona pellucida , other sperm just ca n't get in and they bounce off as they arrive . so now we have a sperm that 's made its way all the way to the plasma membrane of our egg cell . it 's started to bind to the plasma membrane , the acrosome is gone , i 'll erase that here . it 's done its job . the cortical granules have been released , and they 're preventing other sperm from getting in . and we start to actually fuse our plasma membranes of our sperm cell and our egg cell . and that allows for this entire structure to come in . all of the genetic material here within the , all of the genetic material within the nucleus of the sperm cell can start to come out and get released here into the egg . and once we have fusion of genetic material , that is fertilization . so just to recap , we 'll go back to look at our close-up of our sperm . we can see that it 's a very mobile structure evolved basically to get genetic material from the male to the female egg cell . it 's got a tail that propulses it , it 's got mitochondria that feed it energy , it 's got a head with a payload of nuclear material and an acrosome warhead on the tip . the egg cell is a giant cell by comparison . it 's got a specialized layer of glycoproteins on the outside that have a bunch of specialized features and then a bunch of cytoplasm , including mitochondria . and then the process of egg meeting sperm itself is called fertilization . sperm binds to the zona pellucida , the glycoproteins , you have an acrosomal reaction , and then a cortical reaction prevents more than one sperm getting in . and then material , the genetic material of the sperm is transferred . now you 'll notice here that i drew the genetic material from the nucleus coming in . now some of you may be wondering , `` well do n't mitochondria have genetic material as well ? '' well , that 's true . mitochondria do have mitochondrial dna . and potentially , some of these mitochondria can get sucked in during that genetic transfer process as well . but remember , our egg cell had 100 to 200 thousand mitochondrial copies , and our sperm cell only had 75 to 100 . now there 's a little bit of debate , but in the end the male contributes essentially no mitochondria to the zygote that 's formed after the egg and sperm fuse . now , it could be that some of those mitochondria actually do make their way in and then are degraded . we 're not really sure . but given just the numbers , statistically with one to two hundred thousand versus only 75 to 100 , nearly all of the genetic material from the mitochondria is gon na be from the mother anyway .
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organisms that reproduce sexually have got to get their genes together somehow . to do this , they package their genetic material into specialized cells called sex cells .
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where is the corona radiata located ?
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( piano music ) we 're in the mauritshuis museum in the hague , and we 're looking at one of rembrandt 's most famous paintings . this is the anatomy lesson of dr. tulp . this is a typical group portrait , an important type of painting in the dutch republic in the 17th century . this happens to be the guild of surgeons , and regularly they would commission a group portrait to hang in the public space where their guild would meet . once a year , there would be a public dissection where some element of the body would be explicated , and that 's what we 're seeing here . now this is not true to life . in reality , this would have been a much more public event . it 's very likely that the chief surgeon , in this case dr. tulp , would not have been performing the actual dissection , but would have had an assistant do this . but what 's so remarkable here is that rembrandt is reinventing the group portrait . now it 's important to remember that holland , in the 17th century , was largely a protestant nation . the church was no longer a major patron . so artists looked to the professional and middle classes for patronage , and that 's what we have here . and the professional and middle classes and merchant classes looked to artists to create a new kind of art that would meet their needs , and in this case , the need to show off the profession of these men , and specifically in this case , the brilliance of dr. tulp . i think it 's hard to imagine that for so much of history prior to this painting , that as a culture we had so little understanding of the human body . we begin to reinvestigate it during the renaissance , and then here in the baroque era , we begin to impose a scientific investigation on the human body and understand it again . leonardo and michelangelo dissected bodies pretty much in secret so they could understand how the body worked and represent it in their paintings , but up in the north , in the dutch republic , doctors and artists were able to do this more openly . that book at the feet of the cadaver is a reminder of this renewed interest in human anatomy . they 're dissecting a man who had just been hanged . he 's a criminal . look at the way that rembrandt has taken what was a genre of painting where men 's faces were often simply aligned , very much like a contemporary class portrait , which was meant to be a documentation , and he 's created out of that , not only a sense of individuality , but a sense of a shared moment . a narrative story that unfolds , each of these figures doing something slightly different , paying attention to slightly different things . then you have this wonderful varied light with the most light falling on the cadaver and on dr. tulp . he 's lifting up the tendons and exposing , not only the forearm , but the hand as well . it 's a remarkable thing because you have , not only the exposed mechanics of the human hand , but the intact hand of the doctor manipulating that exposed hand , and although we do n't see it directly , the hand of the artist who 's able to produce this painting with his own hand , which is here visible through his brush work . through the paint . i 've always understood what tulp was doing with his left hand as showing how those tendons would move the arm . rembrandt has placed these figures in a pyramid , that is , they 're almost stacked on top of each other so the no face is hidden in part and each figure is given a kind of prominence . but that pyramid is off to the left , and so there 's a real asymmetry , and tulp stands alone on the right . that foreshortened cadaver coming into our space , it 's a horrifying painting for us to look at . although these may have been public events in the 17th century , these are n't things that we 're used to seeing . i 'm interested in the fact that when we see dead bodies painted in the history of western art , it is generally a representation of christ . there are even examples where christ is represented in this kind of foreshortened pose . you might think , for instance , of dead christ by mantegna . but here , science has replaced the spiritual , and it is really a reminder that the 17th century is a point where science really does come to the fore and begins to lay the foundation for the modern world . we see rembrandt bringing drama , and bringing narrative , and bringing storytelling to the group portrait . we saw this , for example , in the night watch , this amazing kind of animation and naturalism removing the stiffness and uniformity of light that had been there in earlier group portraits . and like the later night watch , rembrandt focuses our attention in very specific places . look , for example , at the way which the entire lower left corner is virtually invisible . we can just make out the elbows , the drapes of the figures . we can just make out the chair , but we 're not meant to focus there . our eye is not meant to rest there , but our eye is drawn to the center . of course , the most attention is given to the faces and then the attributes of the success of these figures , and that comes across very clearly in the starched white collars , which are painted with such meticulous skill and were a signal of the wealth of the sitters . think about the effort that went into keeping those snow-white , and then ironing them and starching them so that they were just perfect . it 's so clearly a baroque painting . look at the proximity of that body , the way in which we are part of the circle surrounding this body . there 's an intimacy and directness that you 'd never see in the renaissance . and that reality of that dead body too . we do n't have that tendency to idealize that we see in renaissance painting , but that interest in reality and the mundane , in day to day life that 's part of , especially , dutch baroque paintings . now rembrandt is 25 when he paints this , which is just astounding . at an age when most people would still be students , rembrandt appears to be an accomplished artist . he had just recently moved to amsterdam , and this painting launches his career as the most sought after portrait painter in amsterdam for a couple of decades to come . ( piano music )
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and like the later night watch , rembrandt focuses our attention in very specific places . look , for example , at the way which the entire lower left corner is virtually invisible . we can just make out the elbows , the drapes of the figures .
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what is the book in the bottom right corner ?
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( piano music ) we 're in the mauritshuis museum in the hague , and we 're looking at one of rembrandt 's most famous paintings . this is the anatomy lesson of dr. tulp . this is a typical group portrait , an important type of painting in the dutch republic in the 17th century . this happens to be the guild of surgeons , and regularly they would commission a group portrait to hang in the public space where their guild would meet . once a year , there would be a public dissection where some element of the body would be explicated , and that 's what we 're seeing here . now this is not true to life . in reality , this would have been a much more public event . it 's very likely that the chief surgeon , in this case dr. tulp , would not have been performing the actual dissection , but would have had an assistant do this . but what 's so remarkable here is that rembrandt is reinventing the group portrait . now it 's important to remember that holland , in the 17th century , was largely a protestant nation . the church was no longer a major patron . so artists looked to the professional and middle classes for patronage , and that 's what we have here . and the professional and middle classes and merchant classes looked to artists to create a new kind of art that would meet their needs , and in this case , the need to show off the profession of these men , and specifically in this case , the brilliance of dr. tulp . i think it 's hard to imagine that for so much of history prior to this painting , that as a culture we had so little understanding of the human body . we begin to reinvestigate it during the renaissance , and then here in the baroque era , we begin to impose a scientific investigation on the human body and understand it again . leonardo and michelangelo dissected bodies pretty much in secret so they could understand how the body worked and represent it in their paintings , but up in the north , in the dutch republic , doctors and artists were able to do this more openly . that book at the feet of the cadaver is a reminder of this renewed interest in human anatomy . they 're dissecting a man who had just been hanged . he 's a criminal . look at the way that rembrandt has taken what was a genre of painting where men 's faces were often simply aligned , very much like a contemporary class portrait , which was meant to be a documentation , and he 's created out of that , not only a sense of individuality , but a sense of a shared moment . a narrative story that unfolds , each of these figures doing something slightly different , paying attention to slightly different things . then you have this wonderful varied light with the most light falling on the cadaver and on dr. tulp . he 's lifting up the tendons and exposing , not only the forearm , but the hand as well . it 's a remarkable thing because you have , not only the exposed mechanics of the human hand , but the intact hand of the doctor manipulating that exposed hand , and although we do n't see it directly , the hand of the artist who 's able to produce this painting with his own hand , which is here visible through his brush work . through the paint . i 've always understood what tulp was doing with his left hand as showing how those tendons would move the arm . rembrandt has placed these figures in a pyramid , that is , they 're almost stacked on top of each other so the no face is hidden in part and each figure is given a kind of prominence . but that pyramid is off to the left , and so there 's a real asymmetry , and tulp stands alone on the right . that foreshortened cadaver coming into our space , it 's a horrifying painting for us to look at . although these may have been public events in the 17th century , these are n't things that we 're used to seeing . i 'm interested in the fact that when we see dead bodies painted in the history of western art , it is generally a representation of christ . there are even examples where christ is represented in this kind of foreshortened pose . you might think , for instance , of dead christ by mantegna . but here , science has replaced the spiritual , and it is really a reminder that the 17th century is a point where science really does come to the fore and begins to lay the foundation for the modern world . we see rembrandt bringing drama , and bringing narrative , and bringing storytelling to the group portrait . we saw this , for example , in the night watch , this amazing kind of animation and naturalism removing the stiffness and uniformity of light that had been there in earlier group portraits . and like the later night watch , rembrandt focuses our attention in very specific places . look , for example , at the way which the entire lower left corner is virtually invisible . we can just make out the elbows , the drapes of the figures . we can just make out the chair , but we 're not meant to focus there . our eye is not meant to rest there , but our eye is drawn to the center . of course , the most attention is given to the faces and then the attributes of the success of these figures , and that comes across very clearly in the starched white collars , which are painted with such meticulous skill and were a signal of the wealth of the sitters . think about the effort that went into keeping those snow-white , and then ironing them and starching them so that they were just perfect . it 's so clearly a baroque painting . look at the proximity of that body , the way in which we are part of the circle surrounding this body . there 's an intimacy and directness that you 'd never see in the renaissance . and that reality of that dead body too . we do n't have that tendency to idealize that we see in renaissance painting , but that interest in reality and the mundane , in day to day life that 's part of , especially , dutch baroque paintings . now rembrandt is 25 when he paints this , which is just astounding . at an age when most people would still be students , rembrandt appears to be an accomplished artist . he had just recently moved to amsterdam , and this painting launches his career as the most sought after portrait painter in amsterdam for a couple of decades to come . ( piano music )
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( piano music ) we 're in the mauritshuis museum in the hague , and we 're looking at one of rembrandt 's most famous paintings . this is the anatomy lesson of dr. tulp . this is a typical group portrait , an important type of painting in the dutch republic in the 17th century .
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what are the paintings on either side of `` the anatomy lesson of dr. tulp '' ?
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( piano music ) we 're in the mauritshuis museum in the hague , and we 're looking at one of rembrandt 's most famous paintings . this is the anatomy lesson of dr. tulp . this is a typical group portrait , an important type of painting in the dutch republic in the 17th century . this happens to be the guild of surgeons , and regularly they would commission a group portrait to hang in the public space where their guild would meet . once a year , there would be a public dissection where some element of the body would be explicated , and that 's what we 're seeing here . now this is not true to life . in reality , this would have been a much more public event . it 's very likely that the chief surgeon , in this case dr. tulp , would not have been performing the actual dissection , but would have had an assistant do this . but what 's so remarkable here is that rembrandt is reinventing the group portrait . now it 's important to remember that holland , in the 17th century , was largely a protestant nation . the church was no longer a major patron . so artists looked to the professional and middle classes for patronage , and that 's what we have here . and the professional and middle classes and merchant classes looked to artists to create a new kind of art that would meet their needs , and in this case , the need to show off the profession of these men , and specifically in this case , the brilliance of dr. tulp . i think it 's hard to imagine that for so much of history prior to this painting , that as a culture we had so little understanding of the human body . we begin to reinvestigate it during the renaissance , and then here in the baroque era , we begin to impose a scientific investigation on the human body and understand it again . leonardo and michelangelo dissected bodies pretty much in secret so they could understand how the body worked and represent it in their paintings , but up in the north , in the dutch republic , doctors and artists were able to do this more openly . that book at the feet of the cadaver is a reminder of this renewed interest in human anatomy . they 're dissecting a man who had just been hanged . he 's a criminal . look at the way that rembrandt has taken what was a genre of painting where men 's faces were often simply aligned , very much like a contemporary class portrait , which was meant to be a documentation , and he 's created out of that , not only a sense of individuality , but a sense of a shared moment . a narrative story that unfolds , each of these figures doing something slightly different , paying attention to slightly different things . then you have this wonderful varied light with the most light falling on the cadaver and on dr. tulp . he 's lifting up the tendons and exposing , not only the forearm , but the hand as well . it 's a remarkable thing because you have , not only the exposed mechanics of the human hand , but the intact hand of the doctor manipulating that exposed hand , and although we do n't see it directly , the hand of the artist who 's able to produce this painting with his own hand , which is here visible through his brush work . through the paint . i 've always understood what tulp was doing with his left hand as showing how those tendons would move the arm . rembrandt has placed these figures in a pyramid , that is , they 're almost stacked on top of each other so the no face is hidden in part and each figure is given a kind of prominence . but that pyramid is off to the left , and so there 's a real asymmetry , and tulp stands alone on the right . that foreshortened cadaver coming into our space , it 's a horrifying painting for us to look at . although these may have been public events in the 17th century , these are n't things that we 're used to seeing . i 'm interested in the fact that when we see dead bodies painted in the history of western art , it is generally a representation of christ . there are even examples where christ is represented in this kind of foreshortened pose . you might think , for instance , of dead christ by mantegna . but here , science has replaced the spiritual , and it is really a reminder that the 17th century is a point where science really does come to the fore and begins to lay the foundation for the modern world . we see rembrandt bringing drama , and bringing narrative , and bringing storytelling to the group portrait . we saw this , for example , in the night watch , this amazing kind of animation and naturalism removing the stiffness and uniformity of light that had been there in earlier group portraits . and like the later night watch , rembrandt focuses our attention in very specific places . look , for example , at the way which the entire lower left corner is virtually invisible . we can just make out the elbows , the drapes of the figures . we can just make out the chair , but we 're not meant to focus there . our eye is not meant to rest there , but our eye is drawn to the center . of course , the most attention is given to the faces and then the attributes of the success of these figures , and that comes across very clearly in the starched white collars , which are painted with such meticulous skill and were a signal of the wealth of the sitters . think about the effort that went into keeping those snow-white , and then ironing them and starching them so that they were just perfect . it 's so clearly a baroque painting . look at the proximity of that body , the way in which we are part of the circle surrounding this body . there 's an intimacy and directness that you 'd never see in the renaissance . and that reality of that dead body too . we do n't have that tendency to idealize that we see in renaissance painting , but that interest in reality and the mundane , in day to day life that 's part of , especially , dutch baroque paintings . now rembrandt is 25 when he paints this , which is just astounding . at an age when most people would still be students , rembrandt appears to be an accomplished artist . he had just recently moved to amsterdam , and this painting launches his career as the most sought after portrait painter in amsterdam for a couple of decades to come . ( piano music )
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i 'm interested in the fact that when we see dead bodies painted in the history of western art , it is generally a representation of christ . there are even examples where christ is represented in this kind of foreshortened pose . you might think , for instance , of dead christ by mantegna .
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what does `` foreshortened '' mean ?
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( piano music ) we 're in the mauritshuis museum in the hague , and we 're looking at one of rembrandt 's most famous paintings . this is the anatomy lesson of dr. tulp . this is a typical group portrait , an important type of painting in the dutch republic in the 17th century . this happens to be the guild of surgeons , and regularly they would commission a group portrait to hang in the public space where their guild would meet . once a year , there would be a public dissection where some element of the body would be explicated , and that 's what we 're seeing here . now this is not true to life . in reality , this would have been a much more public event . it 's very likely that the chief surgeon , in this case dr. tulp , would not have been performing the actual dissection , but would have had an assistant do this . but what 's so remarkable here is that rembrandt is reinventing the group portrait . now it 's important to remember that holland , in the 17th century , was largely a protestant nation . the church was no longer a major patron . so artists looked to the professional and middle classes for patronage , and that 's what we have here . and the professional and middle classes and merchant classes looked to artists to create a new kind of art that would meet their needs , and in this case , the need to show off the profession of these men , and specifically in this case , the brilliance of dr. tulp . i think it 's hard to imagine that for so much of history prior to this painting , that as a culture we had so little understanding of the human body . we begin to reinvestigate it during the renaissance , and then here in the baroque era , we begin to impose a scientific investigation on the human body and understand it again . leonardo and michelangelo dissected bodies pretty much in secret so they could understand how the body worked and represent it in their paintings , but up in the north , in the dutch republic , doctors and artists were able to do this more openly . that book at the feet of the cadaver is a reminder of this renewed interest in human anatomy . they 're dissecting a man who had just been hanged . he 's a criminal . look at the way that rembrandt has taken what was a genre of painting where men 's faces were often simply aligned , very much like a contemporary class portrait , which was meant to be a documentation , and he 's created out of that , not only a sense of individuality , but a sense of a shared moment . a narrative story that unfolds , each of these figures doing something slightly different , paying attention to slightly different things . then you have this wonderful varied light with the most light falling on the cadaver and on dr. tulp . he 's lifting up the tendons and exposing , not only the forearm , but the hand as well . it 's a remarkable thing because you have , not only the exposed mechanics of the human hand , but the intact hand of the doctor manipulating that exposed hand , and although we do n't see it directly , the hand of the artist who 's able to produce this painting with his own hand , which is here visible through his brush work . through the paint . i 've always understood what tulp was doing with his left hand as showing how those tendons would move the arm . rembrandt has placed these figures in a pyramid , that is , they 're almost stacked on top of each other so the no face is hidden in part and each figure is given a kind of prominence . but that pyramid is off to the left , and so there 's a real asymmetry , and tulp stands alone on the right . that foreshortened cadaver coming into our space , it 's a horrifying painting for us to look at . although these may have been public events in the 17th century , these are n't things that we 're used to seeing . i 'm interested in the fact that when we see dead bodies painted in the history of western art , it is generally a representation of christ . there are even examples where christ is represented in this kind of foreshortened pose . you might think , for instance , of dead christ by mantegna . but here , science has replaced the spiritual , and it is really a reminder that the 17th century is a point where science really does come to the fore and begins to lay the foundation for the modern world . we see rembrandt bringing drama , and bringing narrative , and bringing storytelling to the group portrait . we saw this , for example , in the night watch , this amazing kind of animation and naturalism removing the stiffness and uniformity of light that had been there in earlier group portraits . and like the later night watch , rembrandt focuses our attention in very specific places . look , for example , at the way which the entire lower left corner is virtually invisible . we can just make out the elbows , the drapes of the figures . we can just make out the chair , but we 're not meant to focus there . our eye is not meant to rest there , but our eye is drawn to the center . of course , the most attention is given to the faces and then the attributes of the success of these figures , and that comes across very clearly in the starched white collars , which are painted with such meticulous skill and were a signal of the wealth of the sitters . think about the effort that went into keeping those snow-white , and then ironing them and starching them so that they were just perfect . it 's so clearly a baroque painting . look at the proximity of that body , the way in which we are part of the circle surrounding this body . there 's an intimacy and directness that you 'd never see in the renaissance . and that reality of that dead body too . we do n't have that tendency to idealize that we see in renaissance painting , but that interest in reality and the mundane , in day to day life that 's part of , especially , dutch baroque paintings . now rembrandt is 25 when he paints this , which is just astounding . at an age when most people would still be students , rembrandt appears to be an accomplished artist . he had just recently moved to amsterdam , and this painting launches his career as the most sought after portrait painter in amsterdam for a couple of decades to come . ( piano music )
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( piano music ) we 're in the mauritshuis museum in the hague , and we 're looking at one of rembrandt 's most famous paintings . this is the anatomy lesson of dr. tulp . this is a typical group portrait , an important type of painting in the dutch republic in the 17th century .
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do these people in the painting with dr.tulp also doctors ?
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