In 1849 a French scientist, Hippolyte Fizeau came up with an ingenious method to measure speed of light. Support us on Patreon: www.patreon.com/bePatron?u=51...
This is based on the presumption that light travels the same speed in all directions!!!! Here is why this is NOT provable: Why The Speed Of Light Is Unmeasurable th-cam.com/video/pTn6Ewhb27k/w-d-xo.html
This is a great video, very educational. I loved the 3d render!!! You are very good at this. Please continue making content! I'd love to see you as one of the main educational channels on yt.
Great visual animation and modern way to determine the speed of C. Interesting side note, it was in 1676 Danish astronomer Ole Roemer determined that light has speed and was not too far off by observing the difference in time of the appearance of Io coming out from behind Jupiter as being either 8 minutes early or 8 minutes late, depending on where earth was in relationship to Jupiter. When earth was farther away on the opposite side of the sun it was late, when it was on the same side of the sun as Jupiter (much closer) it was early. He was off by approximately 1/4 in his speed calculations based on an incorrect assumption of the distance earth was from the sun. It still amazes be that it could be determined with that close of accuracy nearly 350 years ago!
Nice! I’ve heard about this experiment many times in the histories of science but they hardly ever or never go into the details of how it was done. Great video!
I dont think its practical in the example because even if you used a laser pointer with very low beam divergence (say 0.5milliradian), the spot size becomes 8m in radius after travelling the 16km mentioned here (16km*0.5mrad=8m). You'd need to decrease the distance, make it rotate a lot faster and make the teeth sufficiently large that it blocks the spot after the beam is diverged. But he did do it somehow, so I think I'm wrong in what I said above
I searched for a video like this from so many days .I finally got a good video.keep it up.Try to make more videos.Urs way of explanation and animations are perfect.My suggestion is whatever ur situation work a little hard.May u'll get better responses ....
This is based on the presumption that light travels the same speed in all directions!!!! Here is why this is NOT provable: Why The Speed Of Light Is Unmeasurable th-cam.com/video/pTn6Ewhb27k/w-d-xo.html
This is a cool animation and explanation but if the regular mirror was actually positioned like this the light would reflect off it and way over the rest of the apparatus. It needs to be tilting downward to reflect the light back to the cog. Angle of incidence = angel of reflection.
This is based on the presumption that light travels the same speed in all directions!!!! Here is why this is NOT provable: Why The Speed Of Light Is Unmeasurable th-cam.com/video/pTn6Ewhb27k/w-d-xo.html
In 1849..... Where was this 800 meter experiment set up...? What was a strong enough source of light...? How was the cog rotated at precise and constant speed....? What instrument was used to record time in 10,000ths of a second..?
Actually, this is not how you measure the speed of light. It's how you measure the 'round trip speed of light'. We can't yet tell if light travels faster in certain directions and slower in others.
I have noticed when I look at my clock without glasses I can't read the numbers. If I let the light go close to my nose it comes more into focus. So is my nose bending the light? Will the light bend in this experiment because it is close to the wheel?
Now that the speed of light is fundamental constant used to define the metre, the output from this experiment is actually an accurate measure of the distance to the mirror.
Your eyes is camera that captures in limit frame per second . So the limitation is from the Eyes not from the light I mean when you see the light stop blinking that mean your Eyes stop distinguish . Example if you see helicopter in the movie you will see the fan is always turning or slower turning and that related to the camera used limited frame per second not to other parameter. I am not convinced with such experiment. But thanks you have the best explain
I have heard descriptions of this experiment but it was never made clear that the 1:59 total length of the light path was 16 km. I had always thought it was done in the lab which woul require the wheel to be rotating at several thousand rpm.
I was hoping you would explain how the light source worked. The beam has to be bright enough and collimated enough to still be visible at a distance of over 16 km. I assume this was the main barrier to performing an experiment like this before Fizeau. After all, the precision-made gear and adjustable rate of rotation were figured out by clockmakers centuries earlier. And semi-glazed glass had existed for quite a while (though I don't know how well they worked as beam splitters).
the lamp was a regular gas lamp. his apparatus was a very clever tabletop device -- a telescope with the eye piece separated from the body of the telescope, with the cogged wheel and a beam-splitter in between. the telescope is BOTH acting as a collimated light projector and receiver. light is projected out from the telescope, to the mirror, back to the telescope [eg you are looking at your own reflection on a distant mirror, through a telescope which itself is projecting light outward]. the beamsplitter/light src arrangement is kinda similar to a modern front-projecting microscope or optometrist's ophthalmoscope. the margin for error would be small but aligning the mirror would not be very hard because you basically have to just roughly set the mirror, then 'find the spot where you see your own reflection through the telescope' then put the device there.
It must have been tedious to get the return mirror adjusted. I mean, how did he communicate with his helper 8 km away? A corner cube and a laser would have helped!@@PplsChampion
im guessing, but i think it was semaphores + something like 'lets both look at eachother through 2 telescopes, then once we both see the other, one of us will set a mirror to reflect the image at their eyepiece back up the telescope towards the other'. the second telescope is the aligned retroreflector. @@randydewees7338
@@PplsChampion I was wondering if he used an arc lamp, but it seems you're right, it was just "a lamp," presumably a gas streetlight (since an oil lamp couldn't get bright enough). I'm surprised he could even see it over a 17 km distance.
@@randydewees7338 Easy. They could've used a light source + morse code. Put your hand in front of the light source = no light = 0(.). Remove your hand = light = 1(_).
Why it has to be 8000meters why not 10 000 meters . And does is matter vacuum or not vacuum to the speed ? And how do you measure from the start to the finish
You are assuming the speed of light is constant and that there is no affect upon the speed reflecting from the glass. There is also a problem with the observation of the phenomenon. Is the speed different in a different medium? And does light actually travel at a speed?
imagine the laser being directly in the middle of the gap, the next time it will be in that position it will have travelled exactly the distance of two tooths. if it traveled only the distance of one tooth wide then the laser would hit the middle of the tooth and not the following gap.
Good job! It's cool that you're focusing on the experiment, not on the history like other videos.
This is based on the presumption that light travels the same speed in all directions!!!! Here is why this is NOT provable:
Why The Speed Of Light Is Unmeasurable
th-cam.com/video/pTn6Ewhb27k/w-d-xo.html
Yes
@SzymonMajewski history is just for inspiration and motivation if you have both then comes experiment
Really 🤔🤔
bot
Great finally someone who focuses on the details of the experiments and develops the calculations and not only on the history of the experiment.
Wow, excellent video. This is one of the best visualizations of Fizeau I’ve ever seen. Thank you!
This is a great depiction of the experiment! I had heard about this, but it was nicely spelled out here. Thanks!!
This is a great video, very educational. I loved the 3d render!!! You are very good at this. Please continue making content! I'd love to see you as one of the main educational channels on yt.
i hope you make more. this kind of videos has so much potential!
Great visual animation and modern way to determine the speed of C. Interesting side note, it was in 1676 Danish astronomer Ole Roemer determined that light has speed and was not too far off by observing the difference in time of the appearance of Io coming out from behind Jupiter as being either 8 minutes early or 8 minutes late, depending on where earth was in relationship to Jupiter. When earth was farther away on the opposite side of the sun it was late, when it was on the same side of the sun as Jupiter (much closer) it was early. He was off by approximately 1/4 in his speed calculations based on an incorrect assumption of the distance earth was from the sun. It still amazes be that it could be determined with that close of accuracy nearly 350 years ago!
Nice! I’ve heard about this experiment many times in the histories of science but they hardly ever or never go into the details of how it was done. Great video!
I dont think its practical in the example because even if you used a laser pointer with very low beam divergence (say 0.5milliradian), the spot size becomes 8m in radius after travelling the 16km mentioned here (16km*0.5mrad=8m). You'd need to decrease the distance, make it rotate a lot faster and make the teeth sufficiently large that it blocks the spot after the beam is diverged.
But he did do it somehow, so I think I'm wrong in what I said above
@@miron__ in original experiment i dont think they had lasers and they were 8.6km apart
Only 2.4k view ....you deserves millions
I searched for a video like this from so many days .I finally got a good video.keep it up.Try to make more videos.Urs way of explanation and animations are perfect.My suggestion is whatever ur situation work a little hard.May u'll get better responses ....
This is based on the presumption that light travels the same speed in all directions!!!! Here is why this is NOT provable:
Why The Speed Of Light Is Unmeasurable
th-cam.com/video/pTn6Ewhb27k/w-d-xo.html
very good animation and a fullcomplete explanation with the calculation
Thank you for this awesome video.I hope you will keep doing interesting videos like this one.
Excellent demonstration. To the point and exact.
Beautiful explanation, and immaculate derivation. I now fully understand this experiment, as a former math minor.
hands down the best explanation of this experiment i've ever seen
Excellent video, very precise to illustrate the calculation of the speed of light.
Beautiful explanation!
Thank you so much,
Please upload more scientific videos like this..
This is a cool animation and explanation but if the regular mirror was actually positioned like this the light would reflect off it and way over the rest of the apparatus. It needs to be tilting downward to reflect the light back to the cog. Angle of incidence = angel of reflection.
Excellent explanation! I 've finally understood the function of the toothed wheel. Brilliant vid! Thanks 😃
Very nice channel! Instant subscriber. Keep going, it will grow fast soon.
Awesome , thank you for that clear explanation.
This is based on the presumption that light travels the same speed in all directions!!!! Here is why this is NOT provable:
Why The Speed Of Light Is Unmeasurable
th-cam.com/video/pTn6Ewhb27k/w-d-xo.html
Perfectly explained! great work 😍
Just make more videos, you are explaining very well. Thank you!
awesome video, great explanation and diagram. I really enjoy the way you pronounce tooth
Marvelous graphics and explanation.we expect more
Thank you for the animation and amazing explanation!
Great video! Would you also consider animating Foucault’s experiment?
In 1849..... Where was this 800 meter experiment set up...?
What was a strong enough source of light...?
How was the cog rotated at precise and constant speed....?
What instrument was used to record time in 10,000ths of a second..?
Actually, this is not how you measure the speed of light. It's how you measure the 'round trip speed of light'. We can't yet tell if light travels faster in certain directions and slower in others.
First time I completely understand an experiment about speed of light. I should have born in the 19th century but having this TH-cam channel at home.
I have noticed when I look at my clock without glasses I can't read the numbers. If I let the light go close to my nose it comes more into focus. So is my nose bending the light? Will the light bend in this experiment because it is close to the wheel?
Fantastic illustration
Please do more video like thia
Can I ask you what software are you using for the animation and the 3D models?
We need more of this kind of education! Science is super fun when you understand it!
Please, which is the best laser reflector?
At wat distance does the mirror kept from the toothed wheel?
good video, the animation really helped!
Sweet! Can’t wait to test this on my 4 mile laser setup from Christmas
Thanks ayuta team it really helped me a lot :)
I have searching for long to get the clear understanding on measuring speed of light. Thank you for this explaination
doesnt travel the same speed in both directions.your taking an average here
A simple solution to a very complex question , mathematics is fun to work with.
Now that the speed of light is fundamental constant used to define the metre, the output from this experiment is actually an accurate measure of the distance to the mirror.
This assumes light travels at the same speed in both directions.
It is not assumption it is for abovious because it is seen from laws of reflection that angle of incidence is equal to angle of reflection
Yes, we all saw the veritasium video 😄😄
Your eyes is camera that captures in limit frame per second . So the limitation is from the Eyes not from the light I mean when you see the light stop blinking that mean your Eyes stop distinguish . Example if you see helicopter in the movie you will see the fan is always turning or slower turning and that related to the camera used limited frame per second not to other parameter. I am not convinced with such experiment. But thanks you have the best explain
Very good animation and explanation.
Jist a question... How fast does the wheel actually have to spin?
Nice job bro, great video!
This channel is underrated
Very nice, pl explain the diameter of wheel will affect or not ??
Thank you this was so useful!
I have heard descriptions of this experiment but it was never made clear that the 1:59 total length of the light path was 16 km. I had always thought it was done in the lab which woul require the wheel to be rotating at several thousand rpm.
Thanks for the video explaining process 😊
excellent work, thanks for this.
Wonderful, wonderful video
Very good explanation.
Thanks
Great video, keep that content
Well explained sir
What a brilliant experiment.
Great explanation thanks a lot i subscribed
Very good, friend. Clear and clever. I understand it. 👍👍👍🇪🇦🇪🇦🇪🇦
Great work man
Now I'm just curious what the result actually *looked* like. Does the light source just change from blinking rapidly to disappearing altogether?
I wonder ho did they get the light travel 8 km and the reflect exactly back. Did they do t at night?
Thanks for sharing..
Very helpful Sir
Good explanation i love your teaching
Woooow! It's a brilliant explanation with simple Math.
Well done awesome explanation ❤
Wow man! amazing video!
Great video.
excellent and an easy explanation
What should be the angle of regular mirror
Please make more videos like this
Great explanation!
But is the speed in one direction similar to the other?
Too much underrated channel
isn't working with a mirror not as if you restart the lightsource?
Great explanation.
I was hoping you would explain how the light source worked. The beam has to be bright enough and collimated enough to still be visible at a distance of over 16 km. I assume this was the main barrier to performing an experiment like this before Fizeau. After all, the precision-made gear and adjustable rate of rotation were figured out by clockmakers centuries earlier. And semi-glazed glass had existed for quite a while (though I don't know how well they worked as beam splitters).
the lamp was a regular gas lamp. his apparatus was a very clever tabletop device -- a telescope with the eye piece separated from the body of the telescope, with the cogged wheel and a beam-splitter in between. the telescope is BOTH acting as a collimated light projector and receiver. light is projected out from the telescope, to the mirror, back to the telescope [eg you are looking at your own reflection on a distant mirror, through a telescope which itself is projecting light outward]. the beamsplitter/light src arrangement is kinda similar to a modern front-projecting microscope or optometrist's ophthalmoscope. the margin for error would be small but aligning the mirror would not be very hard because you basically have to just roughly set the mirror, then 'find the spot where you see your own reflection through the telescope' then put the device there.
It must have been tedious to get the return mirror adjusted. I mean, how did he communicate with his helper 8 km away? A corner cube and a laser would have helped!@@PplsChampion
im guessing, but i think it was semaphores + something like 'lets both look at eachother through 2 telescopes, then once we both see the other, one of us will set a mirror to reflect the image at their eyepiece back up the telescope towards the other'. the second telescope is the aligned retroreflector. @@randydewees7338
@@PplsChampion I was wondering if he used an arc lamp, but it seems you're right, it was just "a lamp," presumably a gas streetlight (since an oil lamp couldn't get bright enough). I'm surprised he could even see it over a 17 km distance.
@@randydewees7338 Easy. They could've used a light source + morse code. Put your hand in front of the light source = no light = 0(.). Remove your hand = light = 1(_).
This is great! Thank you!
Thank You , really helped.
grt idealogy behind finding the speed of light ..thanks for the vedio
More understanble than the mirror experiment. Its really hard to imagine with that one.
wow that's extremely clever
It was very helpful thank you
I saw this idea in one of the talk but this is better explanation, please add the person who invented this first
Great great video!
But why do we need a large distance between wheel and reflector?
great explanation
😮😮😮well information good show 😅
Well done
what if the beam touch the second or third or fourth tooth periodically each time?
If it touch second wisely then 720/2 ,so 360. if touches 3rd 720/3 !!!
Why it has to be 8000meters why not 10 000 meters . And does is matter vacuum or not vacuum to the speed ?
And how do you measure from the start to the finish
Nice job bro.
And how do you build such contraption in IX century?
Please post the Foucault Method and Michelson Method videos.🙏🏻🙏🏻
Amazing' idea to determine speed of light.
VERY GOOOOOD JOOOB THANKS YOU, YOU SAVE MY LIFE!!!! I LOVE YOU :))))))
Just one question how he kept the laser beam straight for 16 km?
You are assuming the speed of light is constant and that there is no affect upon the speed reflecting from the glass. There is also a problem with the observation of the phenomenon.
Is the speed different in a different medium?
And does light actually travel at a speed?
Sir can u explain y u have taken 720 two times please
Cos you need to move the equivalent of two tooth lengths (one tooth and one gap)
imagine the laser being directly in the middle of the gap, the next time it will be in that position it will have travelled exactly the distance of two tooths. if it traveled only the distance of one tooth wide then the laser would hit the middle of the tooth and not the following gap.