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we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing .
why do some clocks have no numbers ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing .
how do you tell seconds ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing .
in the `` fibonacci '' sequence , what would be the 100 number ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing .
why does `` am '' stands for latin phrase and why does `` pm '' stands for post meridiem ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here .
how do you tell the min if there are no lines ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing .
what is bigger the sun or the moon ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 .
what is 2*795674x99-87+75684 '' x2354= ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock .
what is the difference between the long hand and short hand on a clock ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock .
how do u know the exact number ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock .
how can you tell time without the numbers on the clock ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour .
is n't using labled clocks easier ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
let 's do a few more . what time is it ? so first , we want to look at the hour hand .
why does time go clockwise , specifically ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 .
is the top number 1 ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing .
what does a.m and p.m mean ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour .
how did people make up the terms `` midnight '' and `` noon '' to describe 12 a.m. and 12 p.m. , respectively ?
we 're asked , what time is it ? so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock . so we are in the fourth hour . so the hour is 4 . and then we have to think about the minutes . the minutes are the longer hand , and every one of these lines represent 5 minutes . we start here . this is 0 minutes past the hour , then 5 minutes past the hour , then 10 minutes past the hour . so the time is -- the minutes are 10 , 10 minutes past the hour , and the hour is 4 , or it 's 4:10 . let 's do a few more . what time is it ? so first , we want to look at the hour hand . that 's the shorter hand right over here . it 's at -- let 's see . this is 12 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . and it 's between 9 and 10 . it 's just past 9 . so it 's still in the ninth hour . it has n't gotten to the 10th hour yet . the ninth hour 's from starting with 9 all the way until it 's right almost before it gets to 10 , and then it gets to the 10th hour . so the hour is 9 , and then we want the minutes . well , we can just count from 0 starting at the top of the clock . so 0 , 5 , 10 , 15 , 20 , 25 , 30 . it 's 9:30 . and that also might make sense to you , because we know there are 60 minutes in an hour . and this is exactly halfway around the clock . and so half of 60 is 30 . let 's do one more . what time is it ? so let 's count . this is 12 , 1 -- actually , we can even count backwards . we can go 12 , 11 , 10 . so right now we 're in the 10th hour . the hour hand has passed 10 , but it has n't gotten to 11 yet . so we are in the 10th hour . and how many minutes past the hour are we ? so this would be 0 , 5 , 10 , 15 , 20 minutes past the hour . that 's where the longer hand is pointing . it is 10:20 .
so first , we want to look at the hour hand , which is the shorter hand , and see where it is pointing . so this right over here would have been 12 o'clock , 1 o'clock , 2 o'clock , 3 o'clock , 4 o'clock . and it looks like it 's a little bit past 4 o'clock .
does the clock do anything with angles ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
ca n't we use medium that has extremely high n value to slow speed of light to a level that we can capture , photograph light photons and examine its properties little better ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that .
'energy can not be created or destroyed ' then where did all the initial energy in the big bang come from ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz .
is frequency a measure of the wave ( of light ) frequency ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space .
if so , how does it fit with the idea that light is a particle ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz .
how is a particle supposed to have a frequency ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference .
em radiation travels at c , but if e = hf and e = mc^2 then there must be a mass there , but then it would not be able to travel at c. what am i missing ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too .
there has been something that has been bothering me ever since i entered the realm of physics and chemistry , it 's that how are constants discovered ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
and so what do we call these particles of light ? we call them photons . how do we draw them ?
why is that photons are known to be mass less ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle .
what is the basic difference between a wave and a particle ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that .
why light shows dual nature ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap .
why , exactly , does quantum mechanics contradict einstein 's theory of general relativity ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz .
i know that white light is made up of seven colours ( or 'colors ' in the american spelling ) , so , if each of the colours has its own frequency , is there any specific frequency of white light ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth .
how come plancks constant is sooooo small ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that .
plank 's quantum theory is based on the particle nature of light or wave nature light ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz .
so that equation is sayin to get the energy of a photon particle i need to know the frequency as if it was a wave ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that .
if this light is made up of particles , then they must have mass , therefore also gravity..right ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that .
can someone please help me with the black body radiation experiment and how it proved that light deposits discrete amounts of energy ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that .
does that mean that the electrons get exited from this energy and then fall back but sending out a different wavelenght of light that is n't on the visible spectrum or does the black body just `` keep '' the energy until it 's hot enough for black body radiation ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light .
i used to think waves , ( be it water 's h20 molecules , or light 's photons ) were particles moving together , to form a wave , am i wrong ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that .
can photon has exact energy ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons .
why the photon is all absorbed or not absorbed at all ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that .
why should photon energy be discrete ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that .
so if light behaves as on or off , not in between , could there be a binary system based on light and whether not it 's there ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized .
3 i still do not understand how can waves be localised ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that .
1 ) what 's the difference between intensity and power of energy ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that .
the total energy would be intensity , no ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ?
what is the connection between , e = hf and e = mc^2 ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three .
how can you prove the quantum network of molecular energy of protons ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that .
if so , how can photons ( something without mass ) carry energy ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
and so what do we call these particles of light ? we call them photons . how do we draw them ?
how are photons related with electric and magnetic field ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem .
why a photon can not decay to an electron and positron ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that .
what makes light travel in a straight line ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ...
in terms of communication , could n't we use the fluctuation of colours that were produced in the college test ( to prove the correlation of atomic particles that are nowhere near each other ) to produce morse in some way ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons .
is it possible to force the color option on one side , to change the pattern of another machine elsewhere , with another set of machines reading the diamond 's missing molecule to receive the transmuted information ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that .
planks equation gives you energy for a single photon ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this .
does that mean energy of photon remain constant all the time ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem .
why photon has zero/no mass ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem .
can we use ( momentum ) '' p=mv '' for momentum of a photon ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem .
what is the relativistic mass of a photon ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that .
how much energy ( in j ) is contained in 1.00 mole of 526 nm photons ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics .
with the detector thing at around 0 , what if you absorb two photons at once ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing .
if the energy of the photon was 3 lets say , then would you get 6 units of energy at once ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought .
is n't every other type of electromagnetic radiation on the spectrum a wave ( an oscillating magnetic wave and electronic wave ) , because if so why does light belong on the spectrum ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought .
or does every type of electromagnetic radiation on the spectrum posses particle-wave duality , and if so , how would we know what the waves are made of if we do n't even know what it is ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized .
is this true or due electrons appear in one orbital and then in a higher orbital without any trace of traveling waves or particles ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
and so what do we call these particles of light ? we call them photons . how do we draw them ?
how do we know photons exist , if they have no mass ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that .
how much time passes before an entity absorbs photons again ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ...
when looking at an energy level transition chart that shows emission.. why is the wavelength of the shorter transition ( n=2 to n=1 ) larger than a longer transition ( n=4 to n=1 ) ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized .
0 , what does ''localized '' mean ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water .
discrete amount is like fixed amount ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules .
hello , how is the dimensional analysis working ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ?
why is herz ( oscillation per sec ) times js equal to just j ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
and so what do we call these particles of light ? we call them photons . how do we draw them ?
is magnetic force ( ie a part of electromagnetic force ) also transmitted by photons ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that .
can we use light as energy because of photons in places like power plants and to operate electric things ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing .
is the energy in e=hf means absorb or emitted ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant .
or it means the amount of energy can be stored in a photon ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that .
if it is true that hv > hv ' , where does the energy go ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz .
i understand how sound can be described as a frequency of the change in air pressure , but what is light ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space .
so , does all electromagnetic radiation have this property that it has wave like and particle like behaviour ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized .
how can we use e=mc^2 to see the relation between waves and particles ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it .
is there any way to predict `` disallowed '' frequencies or wavelengths ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz .
but frequency is n't discrete , right ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz .
what are the different light photon frequency 's ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought .
does electromagnetic radiation have specific frequencies ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it .
if we put a really sensitive detector to detect the energy absorbed and we give it 10 photons , is it possible that it will absorb 5 ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that .
if light is made up of particles , why do n't they float in zero gravity ?
- we 've been treating light as a wave , and we 've been drawing it with this continuous wave pattern of oscillating electric and magnetic fields that are traveling in some direction . and why should n't we treat it as a wave ? if you sent it through a small opening , this electromagnetic radiation would spread out , there 'd be diffraction , and that 's what waves do . or , if you let it overlap with itself , if you had some wave in some region , and it lined up perfectly with some other electromagnetic wave , you 'd get constructive interference . if it was out of phase , you 'd get destructive interference . that 's what waves do . why should n't we call electromagnetic radiation a wave ? and that 's what everyone thought . but , in the late 1800s and early 1900s , physicists discovered something shocking . they discovered that light , and all electromagnetic radiation , can display particle-like behavior , too . and i do n't just mean localized in some region of space . waves can get localized . if you sent in some wave here that was a wave pulse , well , that wave pulse is pretty much localized . when it 's traveling through here , it 's going to kind of look like a particle . that 's not really what we mean . we mean something more dramatic . we mean that light , what physicists discovered , is that light and light particles can only deposit certain amount of energy , only discrete amounts of energy . there 's a certain chunk of energy that light can deposit , no less than that . so this is why it 's called quantum mechanics . you 've heard of a quantum leap . quantum mechanics means a discrete jump , no less than that . and so what do we call these particles of light ? we call them photons . how do we draw them ? that 's a little trickier . we know now light can behave like a wave and a particle , so we kind of split the difference sometimes . sometimes you 'll see it like this , where it 's kind of like a wavy particle . so there 's a photon , here 's another photon . basically , this is the problem . this is the main problem with wave particle duality , it 's called . the fact that light , and everything else , for that matter , can behave in a way that shows wavelike characteristics , it can show particle-like characteristics , there 's no classical analog of this . we ca n't envision in our minds anything that we 've ever seen that can do this , that can both behave like a wave and a particle . so it 's impossible , basically , to draw some sort of visual representation , but , you know , it 's always good to draw something . so we draw our photons like this . and so , what i 'm really saying here is , if you had a detector sitting over here that could measure the light energy that it receives from some source of light , what i 'm saying is , if that detector was sensitive enough , you 'd either get no light energy or one jump , or no light energy or , whoop , you absorbed another photon . you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three . you ca n't absorb half of it . you ca n't absorb one unit of energy or two units of energy . you could either absorb the whole thing or nothing . that 's why it 's quantum mechanics . you get this discrete behavior of light depositing all its energy in a particle-like way , or nothing at all . how much energy ? well , we 've got a formula for that . the amount of energy in one photon is determined by this formula . and the first thing in it is planck 's constant . h is the letter we use for planck 's constant , and times f. this is it . it 's a simple formula . f is the frequency . what is planck 's constant ? well , planck was basically the father of quantum mechanics . planck was the first one to figure out what this constant was and to propose that light can only deposit its energy in discrete amounts . so planck 's constant is extremely small ; it 's 6.626 times 10 to the negative 34th joule times seconds . 10 to the negative 34th ? there are n't many other numbers in physics that small . times the frequency -- this is regular frequency . so frequency , number of oscillations per second , measured in hertz . so now we can try to figure out , why did physicists never discover this before ? and the reason is , planck 's constant is so small that the energy of these photons are extremely small . the graininess of this discrete amount of energy that 's getting deposited is so small that it just looks smooth . you ca n't tell that there 's a smallest amount , or at least it 's very hard to tell . so instead of just saying 'three units , ' let 's get specific . for violet light , what 's the energy of one violet photon ? well , the frequency of violet light is 7.5 times 10 to the 14th hertz . so if you take that number times this planck 's constant , 6.626 times 10 to the negative 34th , you 'll get that the energy of one violet photon is about five times 10 to the negative 19th joules . five times ten to the negative 19th , that 's extremely small . that 's hard to see . that 's hard to notice , that energy 's coming in this discrete amount . it 's like water . i mean , water from your sink . water flowing out of your sink looks continuous . we know there 's really discrete water molecules in there , and that you can only get one water molecule , no water molecules , 10 water molecules , discrete amounts of these water molecules , but there 's so many of them and they 're so small , it 's hard to tell that it 's not just completely continuous . the same is happening with this light . this energy 's extremely small . each violet photon has an extremely small amount of energy that it contributes . in fact , if you wanted to know how small it is , a baseball , a professional baseball player , throwing a ball fast , you know , it 's about 100 joules of energy . if you wanted to know how many of these photons , how many of these violet photons would it take to equal the energy of one baseball thrown at major league speed ? it would take about two million trillion of these photons to equal the energy in a baseball that 's thrown . that 's why we do n't see this on a macroscopic scale . for all intents and purposes , for all we care , at a macroscopic level , light 's basically continuous . it can deposit any energy whatsoever , because the scale 's so small here . but if you look at it up close , light can only deposit discrete amounts . now , i do n't mean that light can only deposit small amounts . light can deposit an enormous amount of energy , but it does so in chunks . so think about it this way ... let 's get rid of all this . think about it this way : let 's say you had a detector that 's going to register how much energy it 's absorbing , and we 'll graph it . we 'll graph what this detector 's going to measure , the amount of energy per time that it measures . so we 'll get the amount of energy per time . now , you can absorb huge amounts of energy . and on the detector , on a macroscopic scale , it just might look like this . you know , you 're getting more and more light energy . you 're absorbing more and more energy , collecting more and more energy . but what i 'm saying is that , microscopically , if you look at this , what 's happening is , you 've absorbed one photon here . you absorbed another one , absorbed another one , absorbed a bunch of them . you keep absorbing a bunch of these photons . you can build up a bunch of energy . that 's fine . it 's just if you looked at it close enough , you have this step pattern that 's absorbing photons at a time , certain numbers of them . maybe it absorbs three at one moment , four at another moment . but you ca n't absorb anything in between . it ca n't be completely continuous . it has to be a discrete all-or-nothing moment of absorption of energy that , on a macroscopic scale , looks smooth but on a microscopic scale is highlighted by the fact that light energy is coming in discrete chunks , described by this equation that gives you the energy of individual photons of light .
you could n't get in between . if the quantum jump was three units of energy ... i do n't want to give you a specific unit yet , but , say , three units of energy you could absorb , if that was the amount of energy for that photon , if these photons were carrying three units of energy , you could either absorb no energy whatsoever or you could absorb all three .
what is three units of energy ?
let 's talk about some of the differences between how translation happens in prokaryotic cells and how it happens in eukaryotic cells . and i want to focus mainly on the mrna just before it 's ready to be translated . so let 's start with our prokaryotic mrna and let 's look at our five prime side first . so we have this yellow part right here , and that 's the noncoding region . and it 's called the noncoding region because the ribosome is not actually going to read that part . so that particular sequence of amino acid is not that important . and then after the noncoding region we have the shine-dalgarno sequence . and the shine-delgarno sequence is the site that the ribosome 's going to recognize and bind to . so let 's just throw a ribosome right over here . this is where the prokaryotic ribosome is going to bind . and then after the shine-delgarno sequence , we have another noncoding region . just gon na abbreviate it ncr . and then we have our start codon , which is typically aug , so that tells us to start . and so the ribosome 's going to start translating , it 's going to read this entire section , put together the corresponding polypeptide chain , until it hits the stop codon , which tells it to stop translating . and then we have another noncoding region . let 's look at our eukaryotic mrna . and so it 's pretty similar , but you can see there are some differences . so we 'll start with our five prime side first . so you see this red nucleotide right over here . that 's the five prime cap . and the five prime cap is simply a guanine nucleotide . so i 'm gon na draw a g inside , guanine , and it 's going to have a methyl group somewhere on the molecule . so i 'm gon na draw a methyl group . and the bond between this guanine and the nucleotide right near it is a bond that 's different than the bond that you 'd typically find between two nucleotides . and so that 's really all the five prime cap is . and the five prime cap is actually the ribosomal binding site in eukaryotes . so that means that in eukaryotes , the ribosome 's going to recognize this particular part and bind to it . so after the five prime cap , we have this other noncoding region which the ribosome 's not going to translate . and then the ribosome is going to hit the start codon again . aug tells it to start , and it 's gon na start translating , so it 's going to translate this entire section until it hits the stop codon . and then we have another noncoding region . and then we hit something that looks different than what we 've seen in the prokaryotic mrna , so this section with blue nucleotides , and that 's called the poly-a tail . and the poly-a tail is a bunch of nucleotides that are all a 's , or adenines , so i 'm gon na draw a 's inside all of these nucleotides . and the poly-a tail is actually pretty long , so it 's typically anywhere between 100 and 250 nucleotides long . so that 's pretty long . so i did n't exactly draw it to scale . and the purpose of both the five prime cap , and the poly-a tail is to prevent this mrna from being degraded by enzymes . so it acts as kind of a signal that does not allow enzymes to break it down or degrade it . and so you might be wondering , well , what about prokaryotic mrna ? how come they do n't have anything similar to prevent them from being degraded . and the brief answer to that question is that in prokaryotic cells , transcription , that 's an r , and translation , both happen in the same place . so prokaryotic cells do n't exactly have a nucleus . they have this cytosol and transcription and translation are happening in the same place . and not only are they happening in the same place , but they can actually be happening at the same time . so you can have a piece of mrna that 's being formed , and while it 's being formed , a ribosome will attach to it and being to translate it . but , in eukaryotic cells , things are a little bit different . so transcription ... happens in the nucleus , and translation happens in the cytoplasm where there are ribosomes . and so the mrna , after it 's made , has to travel , from the nucleus to the cytoplasm to where the ribosomes are . and so because it 's traveling this relatively large distance , it 's going to encounter a lot of different things , including enzymes that might break it down . and so it needs this extra protection to prevent it from being damaged in any way . there 's one more difference i want to talk about in how translation happens in prokaryotes and eukaryotes and that is what the first amino acid in the polypeptide chain will be . so in prokaryotic cells , the first amino acid in the chain is always formylmethionine . and formylmethionine is simply the amino acid methionine , but with a formyl group attached . and in case you do n't remember what a formyl group looks like , it looks like that . in eukaryotic cells , the first amino acid in all the polypeptide chains is simply methionine . and it 's interesting to note that formylmethionine actually acts as an alarm system in the human body . so if you had some bacterial cells in your body that were damaged in any way , there would be these formylmethionines floating around , and that tells your body that there are bacteria around , and it 's going to trigger an immune response .
this is where the prokaryotic ribosome is going to bind . and then after the shine-delgarno sequence , we have another noncoding region . just gon na abbreviate it ncr .
what is the function of the shine-delgarno region and why is it only in prokaryotic cells ?
let 's talk about some of the differences between how translation happens in prokaryotic cells and how it happens in eukaryotic cells . and i want to focus mainly on the mrna just before it 's ready to be translated . so let 's start with our prokaryotic mrna and let 's look at our five prime side first . so we have this yellow part right here , and that 's the noncoding region . and it 's called the noncoding region because the ribosome is not actually going to read that part . so that particular sequence of amino acid is not that important . and then after the noncoding region we have the shine-dalgarno sequence . and the shine-delgarno sequence is the site that the ribosome 's going to recognize and bind to . so let 's just throw a ribosome right over here . this is where the prokaryotic ribosome is going to bind . and then after the shine-delgarno sequence , we have another noncoding region . just gon na abbreviate it ncr . and then we have our start codon , which is typically aug , so that tells us to start . and so the ribosome 's going to start translating , it 's going to read this entire section , put together the corresponding polypeptide chain , until it hits the stop codon , which tells it to stop translating . and then we have another noncoding region . let 's look at our eukaryotic mrna . and so it 's pretty similar , but you can see there are some differences . so we 'll start with our five prime side first . so you see this red nucleotide right over here . that 's the five prime cap . and the five prime cap is simply a guanine nucleotide . so i 'm gon na draw a g inside , guanine , and it 's going to have a methyl group somewhere on the molecule . so i 'm gon na draw a methyl group . and the bond between this guanine and the nucleotide right near it is a bond that 's different than the bond that you 'd typically find between two nucleotides . and so that 's really all the five prime cap is . and the five prime cap is actually the ribosomal binding site in eukaryotes . so that means that in eukaryotes , the ribosome 's going to recognize this particular part and bind to it . so after the five prime cap , we have this other noncoding region which the ribosome 's not going to translate . and then the ribosome is going to hit the start codon again . aug tells it to start , and it 's gon na start translating , so it 's going to translate this entire section until it hits the stop codon . and then we have another noncoding region . and then we hit something that looks different than what we 've seen in the prokaryotic mrna , so this section with blue nucleotides , and that 's called the poly-a tail . and the poly-a tail is a bunch of nucleotides that are all a 's , or adenines , so i 'm gon na draw a 's inside all of these nucleotides . and the poly-a tail is actually pretty long , so it 's typically anywhere between 100 and 250 nucleotides long . so that 's pretty long . so i did n't exactly draw it to scale . and the purpose of both the five prime cap , and the poly-a tail is to prevent this mrna from being degraded by enzymes . so it acts as kind of a signal that does not allow enzymes to break it down or degrade it . and so you might be wondering , well , what about prokaryotic mrna ? how come they do n't have anything similar to prevent them from being degraded . and the brief answer to that question is that in prokaryotic cells , transcription , that 's an r , and translation , both happen in the same place . so prokaryotic cells do n't exactly have a nucleus . they have this cytosol and transcription and translation are happening in the same place . and not only are they happening in the same place , but they can actually be happening at the same time . so you can have a piece of mrna that 's being formed , and while it 's being formed , a ribosome will attach to it and being to translate it . but , in eukaryotic cells , things are a little bit different . so transcription ... happens in the nucleus , and translation happens in the cytoplasm where there are ribosomes . and so the mrna , after it 's made , has to travel , from the nucleus to the cytoplasm to where the ribosomes are . and so because it 's traveling this relatively large distance , it 's going to encounter a lot of different things , including enzymes that might break it down . and so it needs this extra protection to prevent it from being damaged in any way . there 's one more difference i want to talk about in how translation happens in prokaryotes and eukaryotes and that is what the first amino acid in the polypeptide chain will be . so in prokaryotic cells , the first amino acid in the chain is always formylmethionine . and formylmethionine is simply the amino acid methionine , but with a formyl group attached . and in case you do n't remember what a formyl group looks like , it looks like that . in eukaryotic cells , the first amino acid in all the polypeptide chains is simply methionine . and it 's interesting to note that formylmethionine actually acts as an alarm system in the human body . so if you had some bacterial cells in your body that were damaged in any way , there would be these formylmethionines floating around , and that tells your body that there are bacteria around , and it 's going to trigger an immune response .
but , in eukaryotic cells , things are a little bit different . so transcription ... happens in the nucleus , and translation happens in the cytoplasm where there are ribosomes . and so the mrna , after it 's made , has to travel , from the nucleus to the cytoplasm to where the ribosomes are .
can translation also occur in the rough endoplasmic reticulum because does n't it also contain ribosomes ?
let 's talk about some of the differences between how translation happens in prokaryotic cells and how it happens in eukaryotic cells . and i want to focus mainly on the mrna just before it 's ready to be translated . so let 's start with our prokaryotic mrna and let 's look at our five prime side first . so we have this yellow part right here , and that 's the noncoding region . and it 's called the noncoding region because the ribosome is not actually going to read that part . so that particular sequence of amino acid is not that important . and then after the noncoding region we have the shine-dalgarno sequence . and the shine-delgarno sequence is the site that the ribosome 's going to recognize and bind to . so let 's just throw a ribosome right over here . this is where the prokaryotic ribosome is going to bind . and then after the shine-delgarno sequence , we have another noncoding region . just gon na abbreviate it ncr . and then we have our start codon , which is typically aug , so that tells us to start . and so the ribosome 's going to start translating , it 's going to read this entire section , put together the corresponding polypeptide chain , until it hits the stop codon , which tells it to stop translating . and then we have another noncoding region . let 's look at our eukaryotic mrna . and so it 's pretty similar , but you can see there are some differences . so we 'll start with our five prime side first . so you see this red nucleotide right over here . that 's the five prime cap . and the five prime cap is simply a guanine nucleotide . so i 'm gon na draw a g inside , guanine , and it 's going to have a methyl group somewhere on the molecule . so i 'm gon na draw a methyl group . and the bond between this guanine and the nucleotide right near it is a bond that 's different than the bond that you 'd typically find between two nucleotides . and so that 's really all the five prime cap is . and the five prime cap is actually the ribosomal binding site in eukaryotes . so that means that in eukaryotes , the ribosome 's going to recognize this particular part and bind to it . so after the five prime cap , we have this other noncoding region which the ribosome 's not going to translate . and then the ribosome is going to hit the start codon again . aug tells it to start , and it 's gon na start translating , so it 's going to translate this entire section until it hits the stop codon . and then we have another noncoding region . and then we hit something that looks different than what we 've seen in the prokaryotic mrna , so this section with blue nucleotides , and that 's called the poly-a tail . and the poly-a tail is a bunch of nucleotides that are all a 's , or adenines , so i 'm gon na draw a 's inside all of these nucleotides . and the poly-a tail is actually pretty long , so it 's typically anywhere between 100 and 250 nucleotides long . so that 's pretty long . so i did n't exactly draw it to scale . and the purpose of both the five prime cap , and the poly-a tail is to prevent this mrna from being degraded by enzymes . so it acts as kind of a signal that does not allow enzymes to break it down or degrade it . and so you might be wondering , well , what about prokaryotic mrna ? how come they do n't have anything similar to prevent them from being degraded . and the brief answer to that question is that in prokaryotic cells , transcription , that 's an r , and translation , both happen in the same place . so prokaryotic cells do n't exactly have a nucleus . they have this cytosol and transcription and translation are happening in the same place . and not only are they happening in the same place , but they can actually be happening at the same time . so you can have a piece of mrna that 's being formed , and while it 's being formed , a ribosome will attach to it and being to translate it . but , in eukaryotic cells , things are a little bit different . so transcription ... happens in the nucleus , and translation happens in the cytoplasm where there are ribosomes . and so the mrna , after it 's made , has to travel , from the nucleus to the cytoplasm to where the ribosomes are . and so because it 's traveling this relatively large distance , it 's going to encounter a lot of different things , including enzymes that might break it down . and so it needs this extra protection to prevent it from being damaged in any way . there 's one more difference i want to talk about in how translation happens in prokaryotes and eukaryotes and that is what the first amino acid in the polypeptide chain will be . so in prokaryotic cells , the first amino acid in the chain is always formylmethionine . and formylmethionine is simply the amino acid methionine , but with a formyl group attached . and in case you do n't remember what a formyl group looks like , it looks like that . in eukaryotic cells , the first amino acid in all the polypeptide chains is simply methionine . and it 's interesting to note that formylmethionine actually acts as an alarm system in the human body . so if you had some bacterial cells in your body that were damaged in any way , there would be these formylmethionines floating around , and that tells your body that there are bacteria around , and it 's going to trigger an immune response .
and the shine-delgarno sequence is the site that the ribosome 's going to recognize and bind to . so let 's just throw a ribosome right over here . this is where the prokaryotic ribosome is going to bind . and then after the shine-delgarno sequence , we have another noncoding region .
but then how come ribosome attach to 5 ' end and continue towards 3 ' end ?
let 's talk about some of the differences between how translation happens in prokaryotic cells and how it happens in eukaryotic cells . and i want to focus mainly on the mrna just before it 's ready to be translated . so let 's start with our prokaryotic mrna and let 's look at our five prime side first . so we have this yellow part right here , and that 's the noncoding region . and it 's called the noncoding region because the ribosome is not actually going to read that part . so that particular sequence of amino acid is not that important . and then after the noncoding region we have the shine-dalgarno sequence . and the shine-delgarno sequence is the site that the ribosome 's going to recognize and bind to . so let 's just throw a ribosome right over here . this is where the prokaryotic ribosome is going to bind . and then after the shine-delgarno sequence , we have another noncoding region . just gon na abbreviate it ncr . and then we have our start codon , which is typically aug , so that tells us to start . and so the ribosome 's going to start translating , it 's going to read this entire section , put together the corresponding polypeptide chain , until it hits the stop codon , which tells it to stop translating . and then we have another noncoding region . let 's look at our eukaryotic mrna . and so it 's pretty similar , but you can see there are some differences . so we 'll start with our five prime side first . so you see this red nucleotide right over here . that 's the five prime cap . and the five prime cap is simply a guanine nucleotide . so i 'm gon na draw a g inside , guanine , and it 's going to have a methyl group somewhere on the molecule . so i 'm gon na draw a methyl group . and the bond between this guanine and the nucleotide right near it is a bond that 's different than the bond that you 'd typically find between two nucleotides . and so that 's really all the five prime cap is . and the five prime cap is actually the ribosomal binding site in eukaryotes . so that means that in eukaryotes , the ribosome 's going to recognize this particular part and bind to it . so after the five prime cap , we have this other noncoding region which the ribosome 's not going to translate . and then the ribosome is going to hit the start codon again . aug tells it to start , and it 's gon na start translating , so it 's going to translate this entire section until it hits the stop codon . and then we have another noncoding region . and then we hit something that looks different than what we 've seen in the prokaryotic mrna , so this section with blue nucleotides , and that 's called the poly-a tail . and the poly-a tail is a bunch of nucleotides that are all a 's , or adenines , so i 'm gon na draw a 's inside all of these nucleotides . and the poly-a tail is actually pretty long , so it 's typically anywhere between 100 and 250 nucleotides long . so that 's pretty long . so i did n't exactly draw it to scale . and the purpose of both the five prime cap , and the poly-a tail is to prevent this mrna from being degraded by enzymes . so it acts as kind of a signal that does not allow enzymes to break it down or degrade it . and so you might be wondering , well , what about prokaryotic mrna ? how come they do n't have anything similar to prevent them from being degraded . and the brief answer to that question is that in prokaryotic cells , transcription , that 's an r , and translation , both happen in the same place . so prokaryotic cells do n't exactly have a nucleus . they have this cytosol and transcription and translation are happening in the same place . and not only are they happening in the same place , but they can actually be happening at the same time . so you can have a piece of mrna that 's being formed , and while it 's being formed , a ribosome will attach to it and being to translate it . but , in eukaryotic cells , things are a little bit different . so transcription ... happens in the nucleus , and translation happens in the cytoplasm where there are ribosomes . and so the mrna , after it 's made , has to travel , from the nucleus to the cytoplasm to where the ribosomes are . and so because it 's traveling this relatively large distance , it 's going to encounter a lot of different things , including enzymes that might break it down . and so it needs this extra protection to prevent it from being damaged in any way . there 's one more difference i want to talk about in how translation happens in prokaryotes and eukaryotes and that is what the first amino acid in the polypeptide chain will be . so in prokaryotic cells , the first amino acid in the chain is always formylmethionine . and formylmethionine is simply the amino acid methionine , but with a formyl group attached . and in case you do n't remember what a formyl group looks like , it looks like that . in eukaryotic cells , the first amino acid in all the polypeptide chains is simply methionine . and it 's interesting to note that formylmethionine actually acts as an alarm system in the human body . so if you had some bacterial cells in your body that were damaged in any way , there would be these formylmethionines floating around , and that tells your body that there are bacteria around , and it 's going to trigger an immune response .
so in prokaryotic cells , the first amino acid in the chain is always formylmethionine . and formylmethionine is simply the amino acid methionine , but with a formyl group attached . and in case you do n't remember what a formyl group looks like , it looks like that .
why is formylmethionine used in prokaryotes instead of just methionine ?
let 's talk about some of the differences between how translation happens in prokaryotic cells and how it happens in eukaryotic cells . and i want to focus mainly on the mrna just before it 's ready to be translated . so let 's start with our prokaryotic mrna and let 's look at our five prime side first . so we have this yellow part right here , and that 's the noncoding region . and it 's called the noncoding region because the ribosome is not actually going to read that part . so that particular sequence of amino acid is not that important . and then after the noncoding region we have the shine-dalgarno sequence . and the shine-delgarno sequence is the site that the ribosome 's going to recognize and bind to . so let 's just throw a ribosome right over here . this is where the prokaryotic ribosome is going to bind . and then after the shine-delgarno sequence , we have another noncoding region . just gon na abbreviate it ncr . and then we have our start codon , which is typically aug , so that tells us to start . and so the ribosome 's going to start translating , it 's going to read this entire section , put together the corresponding polypeptide chain , until it hits the stop codon , which tells it to stop translating . and then we have another noncoding region . let 's look at our eukaryotic mrna . and so it 's pretty similar , but you can see there are some differences . so we 'll start with our five prime side first . so you see this red nucleotide right over here . that 's the five prime cap . and the five prime cap is simply a guanine nucleotide . so i 'm gon na draw a g inside , guanine , and it 's going to have a methyl group somewhere on the molecule . so i 'm gon na draw a methyl group . and the bond between this guanine and the nucleotide right near it is a bond that 's different than the bond that you 'd typically find between two nucleotides . and so that 's really all the five prime cap is . and the five prime cap is actually the ribosomal binding site in eukaryotes . so that means that in eukaryotes , the ribosome 's going to recognize this particular part and bind to it . so after the five prime cap , we have this other noncoding region which the ribosome 's not going to translate . and then the ribosome is going to hit the start codon again . aug tells it to start , and it 's gon na start translating , so it 's going to translate this entire section until it hits the stop codon . and then we have another noncoding region . and then we hit something that looks different than what we 've seen in the prokaryotic mrna , so this section with blue nucleotides , and that 's called the poly-a tail . and the poly-a tail is a bunch of nucleotides that are all a 's , or adenines , so i 'm gon na draw a 's inside all of these nucleotides . and the poly-a tail is actually pretty long , so it 's typically anywhere between 100 and 250 nucleotides long . so that 's pretty long . so i did n't exactly draw it to scale . and the purpose of both the five prime cap , and the poly-a tail is to prevent this mrna from being degraded by enzymes . so it acts as kind of a signal that does not allow enzymes to break it down or degrade it . and so you might be wondering , well , what about prokaryotic mrna ? how come they do n't have anything similar to prevent them from being degraded . and the brief answer to that question is that in prokaryotic cells , transcription , that 's an r , and translation , both happen in the same place . so prokaryotic cells do n't exactly have a nucleus . they have this cytosol and transcription and translation are happening in the same place . and not only are they happening in the same place , but they can actually be happening at the same time . so you can have a piece of mrna that 's being formed , and while it 's being formed , a ribosome will attach to it and being to translate it . but , in eukaryotic cells , things are a little bit different . so transcription ... happens in the nucleus , and translation happens in the cytoplasm where there are ribosomes . and so the mrna , after it 's made , has to travel , from the nucleus to the cytoplasm to where the ribosomes are . and so because it 's traveling this relatively large distance , it 's going to encounter a lot of different things , including enzymes that might break it down . and so it needs this extra protection to prevent it from being damaged in any way . there 's one more difference i want to talk about in how translation happens in prokaryotes and eukaryotes and that is what the first amino acid in the polypeptide chain will be . so in prokaryotic cells , the first amino acid in the chain is always formylmethionine . and formylmethionine is simply the amino acid methionine , but with a formyl group attached . and in case you do n't remember what a formyl group looks like , it looks like that . in eukaryotic cells , the first amino acid in all the polypeptide chains is simply methionine . and it 's interesting to note that formylmethionine actually acts as an alarm system in the human body . so if you had some bacterial cells in your body that were damaged in any way , there would be these formylmethionines floating around , and that tells your body that there are bacteria around , and it 's going to trigger an immune response .
and the bond between this guanine and the nucleotide right near it is a bond that 's different than the bond that you 'd typically find between two nucleotides . and so that 's really all the five prime cap is . and the five prime cap is actually the ribosomal binding site in eukaryotes .
when she says the ribosome binds to the 5'-cap , does that really mean the small subunit binds ?
let 's talk about some of the differences between how translation happens in prokaryotic cells and how it happens in eukaryotic cells . and i want to focus mainly on the mrna just before it 's ready to be translated . so let 's start with our prokaryotic mrna and let 's look at our five prime side first . so we have this yellow part right here , and that 's the noncoding region . and it 's called the noncoding region because the ribosome is not actually going to read that part . so that particular sequence of amino acid is not that important . and then after the noncoding region we have the shine-dalgarno sequence . and the shine-delgarno sequence is the site that the ribosome 's going to recognize and bind to . so let 's just throw a ribosome right over here . this is where the prokaryotic ribosome is going to bind . and then after the shine-delgarno sequence , we have another noncoding region . just gon na abbreviate it ncr . and then we have our start codon , which is typically aug , so that tells us to start . and so the ribosome 's going to start translating , it 's going to read this entire section , put together the corresponding polypeptide chain , until it hits the stop codon , which tells it to stop translating . and then we have another noncoding region . let 's look at our eukaryotic mrna . and so it 's pretty similar , but you can see there are some differences . so we 'll start with our five prime side first . so you see this red nucleotide right over here . that 's the five prime cap . and the five prime cap is simply a guanine nucleotide . so i 'm gon na draw a g inside , guanine , and it 's going to have a methyl group somewhere on the molecule . so i 'm gon na draw a methyl group . and the bond between this guanine and the nucleotide right near it is a bond that 's different than the bond that you 'd typically find between two nucleotides . and so that 's really all the five prime cap is . and the five prime cap is actually the ribosomal binding site in eukaryotes . so that means that in eukaryotes , the ribosome 's going to recognize this particular part and bind to it . so after the five prime cap , we have this other noncoding region which the ribosome 's not going to translate . and then the ribosome is going to hit the start codon again . aug tells it to start , and it 's gon na start translating , so it 's going to translate this entire section until it hits the stop codon . and then we have another noncoding region . and then we hit something that looks different than what we 've seen in the prokaryotic mrna , so this section with blue nucleotides , and that 's called the poly-a tail . and the poly-a tail is a bunch of nucleotides that are all a 's , or adenines , so i 'm gon na draw a 's inside all of these nucleotides . and the poly-a tail is actually pretty long , so it 's typically anywhere between 100 and 250 nucleotides long . so that 's pretty long . so i did n't exactly draw it to scale . and the purpose of both the five prime cap , and the poly-a tail is to prevent this mrna from being degraded by enzymes . so it acts as kind of a signal that does not allow enzymes to break it down or degrade it . and so you might be wondering , well , what about prokaryotic mrna ? how come they do n't have anything similar to prevent them from being degraded . and the brief answer to that question is that in prokaryotic cells , transcription , that 's an r , and translation , both happen in the same place . so prokaryotic cells do n't exactly have a nucleus . they have this cytosol and transcription and translation are happening in the same place . and not only are they happening in the same place , but they can actually be happening at the same time . so you can have a piece of mrna that 's being formed , and while it 's being formed , a ribosome will attach to it and being to translate it . but , in eukaryotic cells , things are a little bit different . so transcription ... happens in the nucleus , and translation happens in the cytoplasm where there are ribosomes . and so the mrna , after it 's made , has to travel , from the nucleus to the cytoplasm to where the ribosomes are . and so because it 's traveling this relatively large distance , it 's going to encounter a lot of different things , including enzymes that might break it down . and so it needs this extra protection to prevent it from being damaged in any way . there 's one more difference i want to talk about in how translation happens in prokaryotes and eukaryotes and that is what the first amino acid in the polypeptide chain will be . so in prokaryotic cells , the first amino acid in the chain is always formylmethionine . and formylmethionine is simply the amino acid methionine , but with a formyl group attached . and in case you do n't remember what a formyl group looks like , it looks like that . in eukaryotic cells , the first amino acid in all the polypeptide chains is simply methionine . and it 's interesting to note that formylmethionine actually acts as an alarm system in the human body . so if you had some bacterial cells in your body that were damaged in any way , there would be these formylmethionines floating around , and that tells your body that there are bacteria around , and it 's going to trigger an immune response .
and it 's called the noncoding region because the ribosome is not actually going to read that part . so that particular sequence of amino acid is not that important . and then after the noncoding region we have the shine-dalgarno sequence .
is the kozak sequence important ?
let 's talk about some of the differences between how translation happens in prokaryotic cells and how it happens in eukaryotic cells . and i want to focus mainly on the mrna just before it 's ready to be translated . so let 's start with our prokaryotic mrna and let 's look at our five prime side first . so we have this yellow part right here , and that 's the noncoding region . and it 's called the noncoding region because the ribosome is not actually going to read that part . so that particular sequence of amino acid is not that important . and then after the noncoding region we have the shine-dalgarno sequence . and the shine-delgarno sequence is the site that the ribosome 's going to recognize and bind to . so let 's just throw a ribosome right over here . this is where the prokaryotic ribosome is going to bind . and then after the shine-delgarno sequence , we have another noncoding region . just gon na abbreviate it ncr . and then we have our start codon , which is typically aug , so that tells us to start . and so the ribosome 's going to start translating , it 's going to read this entire section , put together the corresponding polypeptide chain , until it hits the stop codon , which tells it to stop translating . and then we have another noncoding region . let 's look at our eukaryotic mrna . and so it 's pretty similar , but you can see there are some differences . so we 'll start with our five prime side first . so you see this red nucleotide right over here . that 's the five prime cap . and the five prime cap is simply a guanine nucleotide . so i 'm gon na draw a g inside , guanine , and it 's going to have a methyl group somewhere on the molecule . so i 'm gon na draw a methyl group . and the bond between this guanine and the nucleotide right near it is a bond that 's different than the bond that you 'd typically find between two nucleotides . and so that 's really all the five prime cap is . and the five prime cap is actually the ribosomal binding site in eukaryotes . so that means that in eukaryotes , the ribosome 's going to recognize this particular part and bind to it . so after the five prime cap , we have this other noncoding region which the ribosome 's not going to translate . and then the ribosome is going to hit the start codon again . aug tells it to start , and it 's gon na start translating , so it 's going to translate this entire section until it hits the stop codon . and then we have another noncoding region . and then we hit something that looks different than what we 've seen in the prokaryotic mrna , so this section with blue nucleotides , and that 's called the poly-a tail . and the poly-a tail is a bunch of nucleotides that are all a 's , or adenines , so i 'm gon na draw a 's inside all of these nucleotides . and the poly-a tail is actually pretty long , so it 's typically anywhere between 100 and 250 nucleotides long . so that 's pretty long . so i did n't exactly draw it to scale . and the purpose of both the five prime cap , and the poly-a tail is to prevent this mrna from being degraded by enzymes . so it acts as kind of a signal that does not allow enzymes to break it down or degrade it . and so you might be wondering , well , what about prokaryotic mrna ? how come they do n't have anything similar to prevent them from being degraded . and the brief answer to that question is that in prokaryotic cells , transcription , that 's an r , and translation , both happen in the same place . so prokaryotic cells do n't exactly have a nucleus . they have this cytosol and transcription and translation are happening in the same place . and not only are they happening in the same place , but they can actually be happening at the same time . so you can have a piece of mrna that 's being formed , and while it 's being formed , a ribosome will attach to it and being to translate it . but , in eukaryotic cells , things are a little bit different . so transcription ... happens in the nucleus , and translation happens in the cytoplasm where there are ribosomes . and so the mrna , after it 's made , has to travel , from the nucleus to the cytoplasm to where the ribosomes are . and so because it 's traveling this relatively large distance , it 's going to encounter a lot of different things , including enzymes that might break it down . and so it needs this extra protection to prevent it from being damaged in any way . there 's one more difference i want to talk about in how translation happens in prokaryotes and eukaryotes and that is what the first amino acid in the polypeptide chain will be . so in prokaryotic cells , the first amino acid in the chain is always formylmethionine . and formylmethionine is simply the amino acid methionine , but with a formyl group attached . and in case you do n't remember what a formyl group looks like , it looks like that . in eukaryotic cells , the first amino acid in all the polypeptide chains is simply methionine . and it 's interesting to note that formylmethionine actually acts as an alarm system in the human body . so if you had some bacterial cells in your body that were damaged in any way , there would be these formylmethionines floating around , and that tells your body that there are bacteria around , and it 's going to trigger an immune response .
and it 's called the noncoding region because the ribosome is not actually going to read that part . so that particular sequence of amino acid is not that important . and then after the noncoding region we have the shine-dalgarno sequence . and the shine-delgarno sequence is the site that the ribosome 's going to recognize and bind to .
so if the prokaryotes have the shine-dalgarno sequence on their mrna , where would the kozak sequence be on the eukaryote 's mrna ?
let 's talk about some of the differences between how translation happens in prokaryotic cells and how it happens in eukaryotic cells . and i want to focus mainly on the mrna just before it 's ready to be translated . so let 's start with our prokaryotic mrna and let 's look at our five prime side first . so we have this yellow part right here , and that 's the noncoding region . and it 's called the noncoding region because the ribosome is not actually going to read that part . so that particular sequence of amino acid is not that important . and then after the noncoding region we have the shine-dalgarno sequence . and the shine-delgarno sequence is the site that the ribosome 's going to recognize and bind to . so let 's just throw a ribosome right over here . this is where the prokaryotic ribosome is going to bind . and then after the shine-delgarno sequence , we have another noncoding region . just gon na abbreviate it ncr . and then we have our start codon , which is typically aug , so that tells us to start . and so the ribosome 's going to start translating , it 's going to read this entire section , put together the corresponding polypeptide chain , until it hits the stop codon , which tells it to stop translating . and then we have another noncoding region . let 's look at our eukaryotic mrna . and so it 's pretty similar , but you can see there are some differences . so we 'll start with our five prime side first . so you see this red nucleotide right over here . that 's the five prime cap . and the five prime cap is simply a guanine nucleotide . so i 'm gon na draw a g inside , guanine , and it 's going to have a methyl group somewhere on the molecule . so i 'm gon na draw a methyl group . and the bond between this guanine and the nucleotide right near it is a bond that 's different than the bond that you 'd typically find between two nucleotides . and so that 's really all the five prime cap is . and the five prime cap is actually the ribosomal binding site in eukaryotes . so that means that in eukaryotes , the ribosome 's going to recognize this particular part and bind to it . so after the five prime cap , we have this other noncoding region which the ribosome 's not going to translate . and then the ribosome is going to hit the start codon again . aug tells it to start , and it 's gon na start translating , so it 's going to translate this entire section until it hits the stop codon . and then we have another noncoding region . and then we hit something that looks different than what we 've seen in the prokaryotic mrna , so this section with blue nucleotides , and that 's called the poly-a tail . and the poly-a tail is a bunch of nucleotides that are all a 's , or adenines , so i 'm gon na draw a 's inside all of these nucleotides . and the poly-a tail is actually pretty long , so it 's typically anywhere between 100 and 250 nucleotides long . so that 's pretty long . so i did n't exactly draw it to scale . and the purpose of both the five prime cap , and the poly-a tail is to prevent this mrna from being degraded by enzymes . so it acts as kind of a signal that does not allow enzymes to break it down or degrade it . and so you might be wondering , well , what about prokaryotic mrna ? how come they do n't have anything similar to prevent them from being degraded . and the brief answer to that question is that in prokaryotic cells , transcription , that 's an r , and translation , both happen in the same place . so prokaryotic cells do n't exactly have a nucleus . they have this cytosol and transcription and translation are happening in the same place . and not only are they happening in the same place , but they can actually be happening at the same time . so you can have a piece of mrna that 's being formed , and while it 's being formed , a ribosome will attach to it and being to translate it . but , in eukaryotic cells , things are a little bit different . so transcription ... happens in the nucleus , and translation happens in the cytoplasm where there are ribosomes . and so the mrna , after it 's made , has to travel , from the nucleus to the cytoplasm to where the ribosomes are . and so because it 's traveling this relatively large distance , it 's going to encounter a lot of different things , including enzymes that might break it down . and so it needs this extra protection to prevent it from being damaged in any way . there 's one more difference i want to talk about in how translation happens in prokaryotes and eukaryotes and that is what the first amino acid in the polypeptide chain will be . so in prokaryotic cells , the first amino acid in the chain is always formylmethionine . and formylmethionine is simply the amino acid methionine , but with a formyl group attached . and in case you do n't remember what a formyl group looks like , it looks like that . in eukaryotic cells , the first amino acid in all the polypeptide chains is simply methionine . and it 's interesting to note that formylmethionine actually acts as an alarm system in the human body . so if you had some bacterial cells in your body that were damaged in any way , there would be these formylmethionines floating around , and that tells your body that there are bacteria around , and it 's going to trigger an immune response .
this is where the prokaryotic ribosome is going to bind . and then after the shine-delgarno sequence , we have another noncoding region . just gon na abbreviate it ncr .
why is there another ncr after the shine delgarno sequence ?
let 's talk about some of the differences between how translation happens in prokaryotic cells and how it happens in eukaryotic cells . and i want to focus mainly on the mrna just before it 's ready to be translated . so let 's start with our prokaryotic mrna and let 's look at our five prime side first . so we have this yellow part right here , and that 's the noncoding region . and it 's called the noncoding region because the ribosome is not actually going to read that part . so that particular sequence of amino acid is not that important . and then after the noncoding region we have the shine-dalgarno sequence . and the shine-delgarno sequence is the site that the ribosome 's going to recognize and bind to . so let 's just throw a ribosome right over here . this is where the prokaryotic ribosome is going to bind . and then after the shine-delgarno sequence , we have another noncoding region . just gon na abbreviate it ncr . and then we have our start codon , which is typically aug , so that tells us to start . and so the ribosome 's going to start translating , it 's going to read this entire section , put together the corresponding polypeptide chain , until it hits the stop codon , which tells it to stop translating . and then we have another noncoding region . let 's look at our eukaryotic mrna . and so it 's pretty similar , but you can see there are some differences . so we 'll start with our five prime side first . so you see this red nucleotide right over here . that 's the five prime cap . and the five prime cap is simply a guanine nucleotide . so i 'm gon na draw a g inside , guanine , and it 's going to have a methyl group somewhere on the molecule . so i 'm gon na draw a methyl group . and the bond between this guanine and the nucleotide right near it is a bond that 's different than the bond that you 'd typically find between two nucleotides . and so that 's really all the five prime cap is . and the five prime cap is actually the ribosomal binding site in eukaryotes . so that means that in eukaryotes , the ribosome 's going to recognize this particular part and bind to it . so after the five prime cap , we have this other noncoding region which the ribosome 's not going to translate . and then the ribosome is going to hit the start codon again . aug tells it to start , and it 's gon na start translating , so it 's going to translate this entire section until it hits the stop codon . and then we have another noncoding region . and then we hit something that looks different than what we 've seen in the prokaryotic mrna , so this section with blue nucleotides , and that 's called the poly-a tail . and the poly-a tail is a bunch of nucleotides that are all a 's , or adenines , so i 'm gon na draw a 's inside all of these nucleotides . and the poly-a tail is actually pretty long , so it 's typically anywhere between 100 and 250 nucleotides long . so that 's pretty long . so i did n't exactly draw it to scale . and the purpose of both the five prime cap , and the poly-a tail is to prevent this mrna from being degraded by enzymes . so it acts as kind of a signal that does not allow enzymes to break it down or degrade it . and so you might be wondering , well , what about prokaryotic mrna ? how come they do n't have anything similar to prevent them from being degraded . and the brief answer to that question is that in prokaryotic cells , transcription , that 's an r , and translation , both happen in the same place . so prokaryotic cells do n't exactly have a nucleus . they have this cytosol and transcription and translation are happening in the same place . and not only are they happening in the same place , but they can actually be happening at the same time . so you can have a piece of mrna that 's being formed , and while it 's being formed , a ribosome will attach to it and being to translate it . but , in eukaryotic cells , things are a little bit different . so transcription ... happens in the nucleus , and translation happens in the cytoplasm where there are ribosomes . and so the mrna , after it 's made , has to travel , from the nucleus to the cytoplasm to where the ribosomes are . and so because it 's traveling this relatively large distance , it 's going to encounter a lot of different things , including enzymes that might break it down . and so it needs this extra protection to prevent it from being damaged in any way . there 's one more difference i want to talk about in how translation happens in prokaryotes and eukaryotes and that is what the first amino acid in the polypeptide chain will be . so in prokaryotic cells , the first amino acid in the chain is always formylmethionine . and formylmethionine is simply the amino acid methionine , but with a formyl group attached . and in case you do n't remember what a formyl group looks like , it looks like that . in eukaryotic cells , the first amino acid in all the polypeptide chains is simply methionine . and it 's interesting to note that formylmethionine actually acts as an alarm system in the human body . so if you had some bacterial cells in your body that were damaged in any way , there would be these formylmethionines floating around , and that tells your body that there are bacteria around , and it 's going to trigger an immune response .
so that means that in eukaryotes , the ribosome 's going to recognize this particular part and bind to it . so after the five prime cap , we have this other noncoding region which the ribosome 's not going to translate . and then the ribosome is going to hit the start codon again .
why you said non-coding region after 5'cap and after stop codon ?
we hold these truths to be self-evident , that all men are created equal , that they are endowed by their creator with certain unalienable rights , that among these are life , liberty , and the pursuit of happiness . this is an excerpt of the us declaration of independence , and the united states goes on with its constitution , which gets ratified in 1789 , to articulate a bill of rights , and many will point to the enlightenment as the inspiration for these ideas . thomas jefferson , who wrote the declaration of independence , cited figures like locke as some of mankind 's best thinkers , so at this early date , nations were at least writing these types of words into their declarations of independence , into their constitutions . but despite that , the 20th century is one of the bloodiest centuries in human history . you have world war i , where roughly 17 million people die . in world war ii , 50 to 80 million people die , some directly because of the conflict , but many because of lack of access to food and famine . the chinese are particularly hit . over 15 million died during the japanese occupation of china . this idea of genocide comes about , first with the armenian genocide in the declining ottoman empire where over a million people are believed to have been killed , and then in world war ii , you have the holocaust , where six to 11 million people were killed , roughly two thirds of the jewish population in europe and many others . the russian empire and eventually the soviet union gets especially hit hard in the first half of the 20th century . in world war i alone , three million russians died . shortly after the war , you have a significant russian famine that killed five million people . then in the early thirties , you have the soviet famine , five to seven million people . this is believed to have occurred because of stalin 's attempts to make agriculture collectivized . in the late thirties , you have stalin 's purge , where he goes after political opponents , and it 's believed that he killed as many as three million people . these things were so shocking to the planet that they made attempts to prevent them in the future . in 1920 , out of the trauma of world war i , the league of nations was founded . it was an attempt to prevent things like this in the future , for nations to talk to each other and to coordinate so they do n't go to war , especially at the scale seen in world war i . but clearly , that was unsuccessful , and we have world war ii where even more people die , after which the slightly stronger united nations gets founded , once again with the charter of fostering dialog between nations so that we can prevent these types of trauma for the planet . early on in the newly founded un agenda was this idea of revisiting the ideas of the enlightenment , this idea of human rights , and trying to codify them in international law . in 1948 , you have the universal declaration of human rights that 's drafted by the united nations , and it was an attempt to make a universal declaration of these rights that all humans on the planet have access to . i 'm going to give excerpts of it , and keep a lookout for things that feel awfully close to ideas in the united states declaration of independence , the us constitution , or ideas from the enlightenment . this is part of the preamble . whereas recognition of the inherent dignity and of the equal and unalienable rights of all members of the human family is the foundation of freedom , justice , and peace in the world . whereas disregard and contempt for human rights have resulted in barbarous acts which have outrage the conscience of mankind . remember world war ii just happened . and the advent of a world in which human beings shall enjoy freedom of speech and belief and freedom from fear and want has been proclaimed as the highest aspiration of the common people . now , therefore , the general assembly proclaims this universal declaration of human rights as a common standard of achievement for all peoples and all nations . you might be thinking , `` why did they even have to write this ? '' well , think about it . things like the constitutions of various countries , especially the united states , these only applied to those countries , but now there was an attempt to write down , to codify something that would apply to all human beings , to the entire planet , and here 's just some of the 30 articles to that declaration , to that universal declaration of human rights . all human beings are born free and equal in dignity and rights . they are endowed with reason and conscience and should act towards one another in the spirit of brotherhood . this really feels similar to some of the ideas of locke in the enlightenment that we talk about in other videos . everyone is entitled to all the rights and freedoms set forth in this declaration , without distinction of any kind , such as race , color , sex , language , religion , political , or other opinion , national or social origin , property , birth , or other status . so this is interesting , because even though i start this video with the united states declaration of independence and a discussion of the constitution , slavery in the united states would last for another 80 plus years after the declaration of independence was written . women did n't even have the right to vote until the early 20th century , so beyond this being a universal declaration for the entire planet , the attempt is also to make it clear that it needs to apply to everyone . everyone has the right to life , liberty , and security of person . no one shall be held in slavery or servitude . no one shall be subjected to torture or to cruel , inhuman , or degrading treatment or punishment . everyone charged with a penal offense has the right to be presumed innocent until proved guilty . once again , ideas that seemed very similar to what we see in constitutions like that of the united states . everyone has the right to freedom of thought , conscience , and religion . everyone has the right to freedom of opinion and expression . very similar to the first amendment in the us constitution . everyone has the right to freedom of peaceful assembly and association . no one may be compelled to belong to an association . and article 21 is especially interesting . everyone has the right to take part in the government of his country directly or through freely chosen representatives . everyone has the right of equal access to public service in his country . the will of the people shall be the basis of the authority of government . so this is a big statement . it 's taking a stand , saying that everyone on the planet should be able to live in a democracy and participate in a democracy . the commission that drafted this declaration was chaired by eleanor roosevelt , wife of franklin roosevelt . this is a map of who voted for this declaration and these are the countries in green . who abstained , they just decided not to vote for the declaration , those are the countries in orange , and then you have a few that voted against it . in gray are the countries that were n't part of the united nations at the time . an interesting question looking at this map is to think about why certain countries were willing to vote for it and why other countries decided to abstain at the time . these articles are talking about people having the right to participate in a democracy , the right to be equal , that all people are equal , and in many of these countries , people did not have equal rights . you had severe discrimination in places like south africa . in many of these countries , you did not have a democracy , but there 's a broader question here . it 's nice to be able to write these fairly idealistic ideas , but to what degree does it have an effect , and to what degree can it actually be enforced ? you might cite things like the american civil rights movement , which did echo some of these ideas that were made in the universal declaration of human rights . maybe they helped the civil rights movement , or maybe the civil rights movement would 've happened regardless of what the un did . but at the same time , you have ideas like apartheid . you have racism and discrimination in south africa from the beginning of colonial rule , but it was actually at the exact same time as this declaration that the official policy of apartheid , of government-sanctioned discrimination , of government-sanctioned segregation , preventing racial mingling came into effect and lasted all the way until 1991 . and so one could make an argument , maybe things would 've been worse without the universal declaration of human rights , or maybe the universal declaration of human rights really was n't in a situation to actually effect things like this . in many of the countries around the world , not just the orange ones but often in many of the green ones as well , you continued to see things that go against those ideas of universal human rights . even if the un passes something and if one country does n't want to abide by it , what action can the other countries take ? economic action , maybe sanctions , maybe military action , and to what degree are people actually willing to do that ?
the chinese are particularly hit . over 15 million died during the japanese occupation of china . this idea of genocide comes about , first with the armenian genocide in the declining ottoman empire where over a million people are believed to have been killed , and then in world war ii , you have the holocaust , where six to 11 million people were killed , roughly two thirds of the jewish population in europe and many others .
who was representing china when the charter was signed ?
we hold these truths to be self-evident , that all men are created equal , that they are endowed by their creator with certain unalienable rights , that among these are life , liberty , and the pursuit of happiness . this is an excerpt of the us declaration of independence , and the united states goes on with its constitution , which gets ratified in 1789 , to articulate a bill of rights , and many will point to the enlightenment as the inspiration for these ideas . thomas jefferson , who wrote the declaration of independence , cited figures like locke as some of mankind 's best thinkers , so at this early date , nations were at least writing these types of words into their declarations of independence , into their constitutions . but despite that , the 20th century is one of the bloodiest centuries in human history . you have world war i , where roughly 17 million people die . in world war ii , 50 to 80 million people die , some directly because of the conflict , but many because of lack of access to food and famine . the chinese are particularly hit . over 15 million died during the japanese occupation of china . this idea of genocide comes about , first with the armenian genocide in the declining ottoman empire where over a million people are believed to have been killed , and then in world war ii , you have the holocaust , where six to 11 million people were killed , roughly two thirds of the jewish population in europe and many others . the russian empire and eventually the soviet union gets especially hit hard in the first half of the 20th century . in world war i alone , three million russians died . shortly after the war , you have a significant russian famine that killed five million people . then in the early thirties , you have the soviet famine , five to seven million people . this is believed to have occurred because of stalin 's attempts to make agriculture collectivized . in the late thirties , you have stalin 's purge , where he goes after political opponents , and it 's believed that he killed as many as three million people . these things were so shocking to the planet that they made attempts to prevent them in the future . in 1920 , out of the trauma of world war i , the league of nations was founded . it was an attempt to prevent things like this in the future , for nations to talk to each other and to coordinate so they do n't go to war , especially at the scale seen in world war i . but clearly , that was unsuccessful , and we have world war ii where even more people die , after which the slightly stronger united nations gets founded , once again with the charter of fostering dialog between nations so that we can prevent these types of trauma for the planet . early on in the newly founded un agenda was this idea of revisiting the ideas of the enlightenment , this idea of human rights , and trying to codify them in international law . in 1948 , you have the universal declaration of human rights that 's drafted by the united nations , and it was an attempt to make a universal declaration of these rights that all humans on the planet have access to . i 'm going to give excerpts of it , and keep a lookout for things that feel awfully close to ideas in the united states declaration of independence , the us constitution , or ideas from the enlightenment . this is part of the preamble . whereas recognition of the inherent dignity and of the equal and unalienable rights of all members of the human family is the foundation of freedom , justice , and peace in the world . whereas disregard and contempt for human rights have resulted in barbarous acts which have outrage the conscience of mankind . remember world war ii just happened . and the advent of a world in which human beings shall enjoy freedom of speech and belief and freedom from fear and want has been proclaimed as the highest aspiration of the common people . now , therefore , the general assembly proclaims this universal declaration of human rights as a common standard of achievement for all peoples and all nations . you might be thinking , `` why did they even have to write this ? '' well , think about it . things like the constitutions of various countries , especially the united states , these only applied to those countries , but now there was an attempt to write down , to codify something that would apply to all human beings , to the entire planet , and here 's just some of the 30 articles to that declaration , to that universal declaration of human rights . all human beings are born free and equal in dignity and rights . they are endowed with reason and conscience and should act towards one another in the spirit of brotherhood . this really feels similar to some of the ideas of locke in the enlightenment that we talk about in other videos . everyone is entitled to all the rights and freedoms set forth in this declaration , without distinction of any kind , such as race , color , sex , language , religion , political , or other opinion , national or social origin , property , birth , or other status . so this is interesting , because even though i start this video with the united states declaration of independence and a discussion of the constitution , slavery in the united states would last for another 80 plus years after the declaration of independence was written . women did n't even have the right to vote until the early 20th century , so beyond this being a universal declaration for the entire planet , the attempt is also to make it clear that it needs to apply to everyone . everyone has the right to life , liberty , and security of person . no one shall be held in slavery or servitude . no one shall be subjected to torture or to cruel , inhuman , or degrading treatment or punishment . everyone charged with a penal offense has the right to be presumed innocent until proved guilty . once again , ideas that seemed very similar to what we see in constitutions like that of the united states . everyone has the right to freedom of thought , conscience , and religion . everyone has the right to freedom of opinion and expression . very similar to the first amendment in the us constitution . everyone has the right to freedom of peaceful assembly and association . no one may be compelled to belong to an association . and article 21 is especially interesting . everyone has the right to take part in the government of his country directly or through freely chosen representatives . everyone has the right of equal access to public service in his country . the will of the people shall be the basis of the authority of government . so this is a big statement . it 's taking a stand , saying that everyone on the planet should be able to live in a democracy and participate in a democracy . the commission that drafted this declaration was chaired by eleanor roosevelt , wife of franklin roosevelt . this is a map of who voted for this declaration and these are the countries in green . who abstained , they just decided not to vote for the declaration , those are the countries in orange , and then you have a few that voted against it . in gray are the countries that were n't part of the united nations at the time . an interesting question looking at this map is to think about why certain countries were willing to vote for it and why other countries decided to abstain at the time . these articles are talking about people having the right to participate in a democracy , the right to be equal , that all people are equal , and in many of these countries , people did not have equal rights . you had severe discrimination in places like south africa . in many of these countries , you did not have a democracy , but there 's a broader question here . it 's nice to be able to write these fairly idealistic ideas , but to what degree does it have an effect , and to what degree can it actually be enforced ? you might cite things like the american civil rights movement , which did echo some of these ideas that were made in the universal declaration of human rights . maybe they helped the civil rights movement , or maybe the civil rights movement would 've happened regardless of what the un did . but at the same time , you have ideas like apartheid . you have racism and discrimination in south africa from the beginning of colonial rule , but it was actually at the exact same time as this declaration that the official policy of apartheid , of government-sanctioned discrimination , of government-sanctioned segregation , preventing racial mingling came into effect and lasted all the way until 1991 . and so one could make an argument , maybe things would 've been worse without the universal declaration of human rights , or maybe the universal declaration of human rights really was n't in a situation to actually effect things like this . in many of the countries around the world , not just the orange ones but often in many of the green ones as well , you continued to see things that go against those ideas of universal human rights . even if the un passes something and if one country does n't want to abide by it , what action can the other countries take ? economic action , maybe sanctions , maybe military action , and to what degree are people actually willing to do that ?
who abstained , they just decided not to vote for the declaration , those are the countries in orange , and then you have a few that voted against it . in gray are the countries that were n't part of the united nations at the time . an interesting question looking at this map is to think about why certain countries were willing to vote for it and why other countries decided to abstain at the time .
for example , why do the politicians do n't have to pay tax while we have to ?
so say you just moved from england to the us and you 've got your old school supplies from england and your new school supplies from the us and it 's your first day of school and you get to class and find that your new american paper does n't fit in your old english binder . the paper is too wide , and hangs out . so you cut off the extra and end up with all these strips of paper . and to keep yourself amused during your math class you start playing with them . and by you , i mean arthur h. stone in 1939 . anyway , there 's lots of cool things you do with a strip of paper . you can fold it into shapes and more shapes . maybe spiral it around snugly like this . maybe make it into a square . maybe wrap it into a hexagon with a nice symmetric sort of cycle to the flappy parts . in fact , there 's enough space here to keep wrapping the strip , and the your hexagon is pretty stable . and you 're like . `` i do n't know , hexagons are n't too exciting , but i guess it has symmetry or something . '' maybe you could kinda fold it so the flappy parts are down and the unflappy parts are up . that 's symmetric , and it collapses down into these three triangles , which collapse down into one triangle , and collapsible hexagons are , you suppose , cool enough to at least amuse you a little but during your class . and then , since hexagons have six-way symmetry , you decide to try this three-way fold the other way , with flappy parts up , and are collapsing it down when suddenly the inside of your hexagon decides to open right up what , you close it back up and undo it . everything seems the same as before , the center is not open-uppable . but when you fold it that way again , it , like , flips inside-out . weird . this time , instead of going backwards , you try doing it again and again and again and again . and you want to make one that 's a little less messy , so you try with another strip and tape it nicely into a twisty-foldy loop . you decide that it would be cool to colour the sides , so you get out a highlighter and make one yellow . now you can flip from yellow side to white side . yellow side , white side , yellow side , white side hmm . white side ? what ? where did the yellow side go ? so you go back and this time you colour the white side green , and find that your piece of paper has three sides . yellow , white and green . now this thing is definitely cool . therefore , you need to name it . and since it 's shaped like a hexagon and you flex it and flex rhymes with hex , hexaflexagon it is . that night , you ca n't sleep because you keep thinking about hexaflexagons . and the next day , as soon as you get to your math class you pull out your paper strips . you had made this sort of spirally folded paper that folds into again , the shape of a piece of paper , and you decide to take that and use it like a strip of paper to make a hexaflexagon . which would totally work , but it feels sturdier with the extra paper . and you color the three sides and are like , orange , yellow , pink . and you 're sort of trying to pay attention to class . math , yeah . orange , yellow , pink . orange , yellow , white ? wait a second . okay , so you colour that one green . and now it ; s orange , yellow , green , orange , yellow , green . who knows where the pink side went ? oh , there it is . now it 's back to orange , yellow , pink . orange , yellow , pink . hmm . blue . yellow , pink , blue . yellow , pink , blue . yellow , pink , huh . with the old flexagon , you could only flex it one way , flappy way up . but now there 's more flaps . so maybe you can fold it both ways . yes , one goes from pink to blue , but the other , from pink to orange . and now , one way goes from orange to yellow , but the other way goes from orange to neon yellow . during lunch you want to show this off to one of your new friends , bryant tuckerman . you start with the original , simple , three-faced hexaflexagon , which you call the trihexaflexagon . and he 's like , whoa ! and wants to learn how to make one . and you are like , it 's easy ! just start with a paper strip , fold it into equilateral traingles , and you 'll need nine of them , and you fold them around into this cycle and make sure it 's all symmetric . the flat parts are diamonds , and if they 're not , then you 're doing it wrong . and then you just tape the first triangle to the last along the edge , and you 're good . but tuckerman does n't have tape . after all , it was invented only 10 years ago . so he cuts out ten triangles instead of nine , and then glues the first to the last . then you show him how to flex it by pinching around a flappy part and pushing in on the opposite side to make it flat and traingly , and then opening from the centre . you decide to start a flexagon committee together to explore the mysteries of flexagotion , but that will have to wait until next time .
and by you , i mean arthur h. stone in 1939 . anyway , there 's lots of cool things you do with a strip of paper . you can fold it into shapes and more shapes .
is there any relationship between a hexaflexagon and a mobius strip ?
so say you just moved from england to the us and you 've got your old school supplies from england and your new school supplies from the us and it 's your first day of school and you get to class and find that your new american paper does n't fit in your old english binder . the paper is too wide , and hangs out . so you cut off the extra and end up with all these strips of paper . and to keep yourself amused during your math class you start playing with them . and by you , i mean arthur h. stone in 1939 . anyway , there 's lots of cool things you do with a strip of paper . you can fold it into shapes and more shapes . maybe spiral it around snugly like this . maybe make it into a square . maybe wrap it into a hexagon with a nice symmetric sort of cycle to the flappy parts . in fact , there 's enough space here to keep wrapping the strip , and the your hexagon is pretty stable . and you 're like . `` i do n't know , hexagons are n't too exciting , but i guess it has symmetry or something . '' maybe you could kinda fold it so the flappy parts are down and the unflappy parts are up . that 's symmetric , and it collapses down into these three triangles , which collapse down into one triangle , and collapsible hexagons are , you suppose , cool enough to at least amuse you a little but during your class . and then , since hexagons have six-way symmetry , you decide to try this three-way fold the other way , with flappy parts up , and are collapsing it down when suddenly the inside of your hexagon decides to open right up what , you close it back up and undo it . everything seems the same as before , the center is not open-uppable . but when you fold it that way again , it , like , flips inside-out . weird . this time , instead of going backwards , you try doing it again and again and again and again . and you want to make one that 's a little less messy , so you try with another strip and tape it nicely into a twisty-foldy loop . you decide that it would be cool to colour the sides , so you get out a highlighter and make one yellow . now you can flip from yellow side to white side . yellow side , white side , yellow side , white side hmm . white side ? what ? where did the yellow side go ? so you go back and this time you colour the white side green , and find that your piece of paper has three sides . yellow , white and green . now this thing is definitely cool . therefore , you need to name it . and since it 's shaped like a hexagon and you flex it and flex rhymes with hex , hexaflexagon it is . that night , you ca n't sleep because you keep thinking about hexaflexagons . and the next day , as soon as you get to your math class you pull out your paper strips . you had made this sort of spirally folded paper that folds into again , the shape of a piece of paper , and you decide to take that and use it like a strip of paper to make a hexaflexagon . which would totally work , but it feels sturdier with the extra paper . and you color the three sides and are like , orange , yellow , pink . and you 're sort of trying to pay attention to class . math , yeah . orange , yellow , pink . orange , yellow , white ? wait a second . okay , so you colour that one green . and now it ; s orange , yellow , green , orange , yellow , green . who knows where the pink side went ? oh , there it is . now it 's back to orange , yellow , pink . orange , yellow , pink . hmm . blue . yellow , pink , blue . yellow , pink , blue . yellow , pink , huh . with the old flexagon , you could only flex it one way , flappy way up . but now there 's more flaps . so maybe you can fold it both ways . yes , one goes from pink to blue , but the other , from pink to orange . and now , one way goes from orange to yellow , but the other way goes from orange to neon yellow . during lunch you want to show this off to one of your new friends , bryant tuckerman . you start with the original , simple , three-faced hexaflexagon , which you call the trihexaflexagon . and he 's like , whoa ! and wants to learn how to make one . and you are like , it 's easy ! just start with a paper strip , fold it into equilateral traingles , and you 'll need nine of them , and you fold them around into this cycle and make sure it 's all symmetric . the flat parts are diamonds , and if they 're not , then you 're doing it wrong . and then you just tape the first triangle to the last along the edge , and you 're good . but tuckerman does n't have tape . after all , it was invented only 10 years ago . so he cuts out ten triangles instead of nine , and then glues the first to the last . then you show him how to flex it by pinching around a flappy part and pushing in on the opposite side to make it flat and traingly , and then opening from the centre . you decide to start a flexagon committee together to explore the mysteries of flexagotion , but that will have to wait until next time .
maybe spiral it around snugly like this . maybe make it into a square . maybe wrap it into a hexagon with a nice symmetric sort of cycle to the flappy parts .
can you please show me how to make a hexaflexagon in slow motion ?
so say you just moved from england to the us and you 've got your old school supplies from england and your new school supplies from the us and it 's your first day of school and you get to class and find that your new american paper does n't fit in your old english binder . the paper is too wide , and hangs out . so you cut off the extra and end up with all these strips of paper . and to keep yourself amused during your math class you start playing with them . and by you , i mean arthur h. stone in 1939 . anyway , there 's lots of cool things you do with a strip of paper . you can fold it into shapes and more shapes . maybe spiral it around snugly like this . maybe make it into a square . maybe wrap it into a hexagon with a nice symmetric sort of cycle to the flappy parts . in fact , there 's enough space here to keep wrapping the strip , and the your hexagon is pretty stable . and you 're like . `` i do n't know , hexagons are n't too exciting , but i guess it has symmetry or something . '' maybe you could kinda fold it so the flappy parts are down and the unflappy parts are up . that 's symmetric , and it collapses down into these three triangles , which collapse down into one triangle , and collapsible hexagons are , you suppose , cool enough to at least amuse you a little but during your class . and then , since hexagons have six-way symmetry , you decide to try this three-way fold the other way , with flappy parts up , and are collapsing it down when suddenly the inside of your hexagon decides to open right up what , you close it back up and undo it . everything seems the same as before , the center is not open-uppable . but when you fold it that way again , it , like , flips inside-out . weird . this time , instead of going backwards , you try doing it again and again and again and again . and you want to make one that 's a little less messy , so you try with another strip and tape it nicely into a twisty-foldy loop . you decide that it would be cool to colour the sides , so you get out a highlighter and make one yellow . now you can flip from yellow side to white side . yellow side , white side , yellow side , white side hmm . white side ? what ? where did the yellow side go ? so you go back and this time you colour the white side green , and find that your piece of paper has three sides . yellow , white and green . now this thing is definitely cool . therefore , you need to name it . and since it 's shaped like a hexagon and you flex it and flex rhymes with hex , hexaflexagon it is . that night , you ca n't sleep because you keep thinking about hexaflexagons . and the next day , as soon as you get to your math class you pull out your paper strips . you had made this sort of spirally folded paper that folds into again , the shape of a piece of paper , and you decide to take that and use it like a strip of paper to make a hexaflexagon . which would totally work , but it feels sturdier with the extra paper . and you color the three sides and are like , orange , yellow , pink . and you 're sort of trying to pay attention to class . math , yeah . orange , yellow , pink . orange , yellow , white ? wait a second . okay , so you colour that one green . and now it ; s orange , yellow , green , orange , yellow , green . who knows where the pink side went ? oh , there it is . now it 's back to orange , yellow , pink . orange , yellow , pink . hmm . blue . yellow , pink , blue . yellow , pink , blue . yellow , pink , huh . with the old flexagon , you could only flex it one way , flappy way up . but now there 's more flaps . so maybe you can fold it both ways . yes , one goes from pink to blue , but the other , from pink to orange . and now , one way goes from orange to yellow , but the other way goes from orange to neon yellow . during lunch you want to show this off to one of your new friends , bryant tuckerman . you start with the original , simple , three-faced hexaflexagon , which you call the trihexaflexagon . and he 's like , whoa ! and wants to learn how to make one . and you are like , it 's easy ! just start with a paper strip , fold it into equilateral traingles , and you 'll need nine of them , and you fold them around into this cycle and make sure it 's all symmetric . the flat parts are diamonds , and if they 're not , then you 're doing it wrong . and then you just tape the first triangle to the last along the edge , and you 're good . but tuckerman does n't have tape . after all , it was invented only 10 years ago . so he cuts out ten triangles instead of nine , and then glues the first to the last . then you show him how to flex it by pinching around a flappy part and pushing in on the opposite side to make it flat and traingly , and then opening from the centre . you decide to start a flexagon committee together to explore the mysteries of flexagotion , but that will have to wait until next time .
yellow , pink , huh . with the old flexagon , you could only flex it one way , flappy way up . but now there 's more flaps .
is the hexaflexagon concept currently being incorporated in technology as a way to store satellite dishes , and solar panels , when not in use ?
so say you just moved from england to the us and you 've got your old school supplies from england and your new school supplies from the us and it 's your first day of school and you get to class and find that your new american paper does n't fit in your old english binder . the paper is too wide , and hangs out . so you cut off the extra and end up with all these strips of paper . and to keep yourself amused during your math class you start playing with them . and by you , i mean arthur h. stone in 1939 . anyway , there 's lots of cool things you do with a strip of paper . you can fold it into shapes and more shapes . maybe spiral it around snugly like this . maybe make it into a square . maybe wrap it into a hexagon with a nice symmetric sort of cycle to the flappy parts . in fact , there 's enough space here to keep wrapping the strip , and the your hexagon is pretty stable . and you 're like . `` i do n't know , hexagons are n't too exciting , but i guess it has symmetry or something . '' maybe you could kinda fold it so the flappy parts are down and the unflappy parts are up . that 's symmetric , and it collapses down into these three triangles , which collapse down into one triangle , and collapsible hexagons are , you suppose , cool enough to at least amuse you a little but during your class . and then , since hexagons have six-way symmetry , you decide to try this three-way fold the other way , with flappy parts up , and are collapsing it down when suddenly the inside of your hexagon decides to open right up what , you close it back up and undo it . everything seems the same as before , the center is not open-uppable . but when you fold it that way again , it , like , flips inside-out . weird . this time , instead of going backwards , you try doing it again and again and again and again . and you want to make one that 's a little less messy , so you try with another strip and tape it nicely into a twisty-foldy loop . you decide that it would be cool to colour the sides , so you get out a highlighter and make one yellow . now you can flip from yellow side to white side . yellow side , white side , yellow side , white side hmm . white side ? what ? where did the yellow side go ? so you go back and this time you colour the white side green , and find that your piece of paper has three sides . yellow , white and green . now this thing is definitely cool . therefore , you need to name it . and since it 's shaped like a hexagon and you flex it and flex rhymes with hex , hexaflexagon it is . that night , you ca n't sleep because you keep thinking about hexaflexagons . and the next day , as soon as you get to your math class you pull out your paper strips . you had made this sort of spirally folded paper that folds into again , the shape of a piece of paper , and you decide to take that and use it like a strip of paper to make a hexaflexagon . which would totally work , but it feels sturdier with the extra paper . and you color the three sides and are like , orange , yellow , pink . and you 're sort of trying to pay attention to class . math , yeah . orange , yellow , pink . orange , yellow , white ? wait a second . okay , so you colour that one green . and now it ; s orange , yellow , green , orange , yellow , green . who knows where the pink side went ? oh , there it is . now it 's back to orange , yellow , pink . orange , yellow , pink . hmm . blue . yellow , pink , blue . yellow , pink , blue . yellow , pink , huh . with the old flexagon , you could only flex it one way , flappy way up . but now there 's more flaps . so maybe you can fold it both ways . yes , one goes from pink to blue , but the other , from pink to orange . and now , one way goes from orange to yellow , but the other way goes from orange to neon yellow . during lunch you want to show this off to one of your new friends , bryant tuckerman . you start with the original , simple , three-faced hexaflexagon , which you call the trihexaflexagon . and he 's like , whoa ! and wants to learn how to make one . and you are like , it 's easy ! just start with a paper strip , fold it into equilateral traingles , and you 'll need nine of them , and you fold them around into this cycle and make sure it 's all symmetric . the flat parts are diamonds , and if they 're not , then you 're doing it wrong . and then you just tape the first triangle to the last along the edge , and you 're good . but tuckerman does n't have tape . after all , it was invented only 10 years ago . so he cuts out ten triangles instead of nine , and then glues the first to the last . then you show him how to flex it by pinching around a flappy part and pushing in on the opposite side to make it flat and traingly , and then opening from the centre . you decide to start a flexagon committee together to explore the mysteries of flexagotion , but that will have to wait until next time .
in fact , there 's enough space here to keep wrapping the strip , and the your hexagon is pretty stable . and you 're like . `` i do n't know , hexagons are n't too exciting , but i guess it has symmetry or something . ''
would it be possible to implement an umbrella-like collapsing method ( triangles within a circular shape ) for satellites , too ?
so say you just moved from england to the us and you 've got your old school supplies from england and your new school supplies from the us and it 's your first day of school and you get to class and find that your new american paper does n't fit in your old english binder . the paper is too wide , and hangs out . so you cut off the extra and end up with all these strips of paper . and to keep yourself amused during your math class you start playing with them . and by you , i mean arthur h. stone in 1939 . anyway , there 's lots of cool things you do with a strip of paper . you can fold it into shapes and more shapes . maybe spiral it around snugly like this . maybe make it into a square . maybe wrap it into a hexagon with a nice symmetric sort of cycle to the flappy parts . in fact , there 's enough space here to keep wrapping the strip , and the your hexagon is pretty stable . and you 're like . `` i do n't know , hexagons are n't too exciting , but i guess it has symmetry or something . '' maybe you could kinda fold it so the flappy parts are down and the unflappy parts are up . that 's symmetric , and it collapses down into these three triangles , which collapse down into one triangle , and collapsible hexagons are , you suppose , cool enough to at least amuse you a little but during your class . and then , since hexagons have six-way symmetry , you decide to try this three-way fold the other way , with flappy parts up , and are collapsing it down when suddenly the inside of your hexagon decides to open right up what , you close it back up and undo it . everything seems the same as before , the center is not open-uppable . but when you fold it that way again , it , like , flips inside-out . weird . this time , instead of going backwards , you try doing it again and again and again and again . and you want to make one that 's a little less messy , so you try with another strip and tape it nicely into a twisty-foldy loop . you decide that it would be cool to colour the sides , so you get out a highlighter and make one yellow . now you can flip from yellow side to white side . yellow side , white side , yellow side , white side hmm . white side ? what ? where did the yellow side go ? so you go back and this time you colour the white side green , and find that your piece of paper has three sides . yellow , white and green . now this thing is definitely cool . therefore , you need to name it . and since it 's shaped like a hexagon and you flex it and flex rhymes with hex , hexaflexagon it is . that night , you ca n't sleep because you keep thinking about hexaflexagons . and the next day , as soon as you get to your math class you pull out your paper strips . you had made this sort of spirally folded paper that folds into again , the shape of a piece of paper , and you decide to take that and use it like a strip of paper to make a hexaflexagon . which would totally work , but it feels sturdier with the extra paper . and you color the three sides and are like , orange , yellow , pink . and you 're sort of trying to pay attention to class . math , yeah . orange , yellow , pink . orange , yellow , white ? wait a second . okay , so you colour that one green . and now it ; s orange , yellow , green , orange , yellow , green . who knows where the pink side went ? oh , there it is . now it 's back to orange , yellow , pink . orange , yellow , pink . hmm . blue . yellow , pink , blue . yellow , pink , blue . yellow , pink , huh . with the old flexagon , you could only flex it one way , flappy way up . but now there 's more flaps . so maybe you can fold it both ways . yes , one goes from pink to blue , but the other , from pink to orange . and now , one way goes from orange to yellow , but the other way goes from orange to neon yellow . during lunch you want to show this off to one of your new friends , bryant tuckerman . you start with the original , simple , three-faced hexaflexagon , which you call the trihexaflexagon . and he 's like , whoa ! and wants to learn how to make one . and you are like , it 's easy ! just start with a paper strip , fold it into equilateral traingles , and you 'll need nine of them , and you fold them around into this cycle and make sure it 's all symmetric . the flat parts are diamonds , and if they 're not , then you 're doing it wrong . and then you just tape the first triangle to the last along the edge , and you 're good . but tuckerman does n't have tape . after all , it was invented only 10 years ago . so he cuts out ten triangles instead of nine , and then glues the first to the last . then you show him how to flex it by pinching around a flappy part and pushing in on the opposite side to make it flat and traingly , and then opening from the centre . you decide to start a flexagon committee together to explore the mysteries of flexagotion , but that will have to wait until next time .
and you want to make one that 's a little less messy , so you try with another strip and tape it nicely into a twisty-foldy loop . you decide that it would be cool to colour the sides , so you get out a highlighter and make one yellow . now you can flip from yellow side to white side .
is it possible to make a hexaflexagon that has more than six sides ?
so say you just moved from england to the us and you 've got your old school supplies from england and your new school supplies from the us and it 's your first day of school and you get to class and find that your new american paper does n't fit in your old english binder . the paper is too wide , and hangs out . so you cut off the extra and end up with all these strips of paper . and to keep yourself amused during your math class you start playing with them . and by you , i mean arthur h. stone in 1939 . anyway , there 's lots of cool things you do with a strip of paper . you can fold it into shapes and more shapes . maybe spiral it around snugly like this . maybe make it into a square . maybe wrap it into a hexagon with a nice symmetric sort of cycle to the flappy parts . in fact , there 's enough space here to keep wrapping the strip , and the your hexagon is pretty stable . and you 're like . `` i do n't know , hexagons are n't too exciting , but i guess it has symmetry or something . '' maybe you could kinda fold it so the flappy parts are down and the unflappy parts are up . that 's symmetric , and it collapses down into these three triangles , which collapse down into one triangle , and collapsible hexagons are , you suppose , cool enough to at least amuse you a little but during your class . and then , since hexagons have six-way symmetry , you decide to try this three-way fold the other way , with flappy parts up , and are collapsing it down when suddenly the inside of your hexagon decides to open right up what , you close it back up and undo it . everything seems the same as before , the center is not open-uppable . but when you fold it that way again , it , like , flips inside-out . weird . this time , instead of going backwards , you try doing it again and again and again and again . and you want to make one that 's a little less messy , so you try with another strip and tape it nicely into a twisty-foldy loop . you decide that it would be cool to colour the sides , so you get out a highlighter and make one yellow . now you can flip from yellow side to white side . yellow side , white side , yellow side , white side hmm . white side ? what ? where did the yellow side go ? so you go back and this time you colour the white side green , and find that your piece of paper has three sides . yellow , white and green . now this thing is definitely cool . therefore , you need to name it . and since it 's shaped like a hexagon and you flex it and flex rhymes with hex , hexaflexagon it is . that night , you ca n't sleep because you keep thinking about hexaflexagons . and the next day , as soon as you get to your math class you pull out your paper strips . you had made this sort of spirally folded paper that folds into again , the shape of a piece of paper , and you decide to take that and use it like a strip of paper to make a hexaflexagon . which would totally work , but it feels sturdier with the extra paper . and you color the three sides and are like , orange , yellow , pink . and you 're sort of trying to pay attention to class . math , yeah . orange , yellow , pink . orange , yellow , white ? wait a second . okay , so you colour that one green . and now it ; s orange , yellow , green , orange , yellow , green . who knows where the pink side went ? oh , there it is . now it 's back to orange , yellow , pink . orange , yellow , pink . hmm . blue . yellow , pink , blue . yellow , pink , blue . yellow , pink , huh . with the old flexagon , you could only flex it one way , flappy way up . but now there 's more flaps . so maybe you can fold it both ways . yes , one goes from pink to blue , but the other , from pink to orange . and now , one way goes from orange to yellow , but the other way goes from orange to neon yellow . during lunch you want to show this off to one of your new friends , bryant tuckerman . you start with the original , simple , three-faced hexaflexagon , which you call the trihexaflexagon . and he 's like , whoa ! and wants to learn how to make one . and you are like , it 's easy ! just start with a paper strip , fold it into equilateral traingles , and you 'll need nine of them , and you fold them around into this cycle and make sure it 's all symmetric . the flat parts are diamonds , and if they 're not , then you 're doing it wrong . and then you just tape the first triangle to the last along the edge , and you 're good . but tuckerman does n't have tape . after all , it was invented only 10 years ago . so he cuts out ten triangles instead of nine , and then glues the first to the last . then you show him how to flex it by pinching around a flappy part and pushing in on the opposite side to make it flat and traingly , and then opening from the centre . you decide to start a flexagon committee together to explore the mysteries of flexagotion , but that will have to wait until next time .
maybe spiral it around snugly like this . maybe make it into a square . maybe wrap it into a hexagon with a nice symmetric sort of cycle to the flappy parts .
how in the world do you make a hexaflexagon ?