halfmoon26 The question is simply a matter of relativity. How many Shlongs per second does light travel when perceived by whom? It certainly isn't a constant!
For all of you saying this isn't a good experiment because he's not in vacuum, his calculation is actually only off in a true vacuum by about 1.6429% considering the speed of light in a vacuum is exactly 299,792,458 m/s. Not a huge margin if you don't need to be extremely precise, which usually isn't needed in simple calculations. 60ft/60ns a really good approximation, aside from the fact that you're using feet.
@@drfazailzia8830 no, light slows down a lot in water and ice. It travels quite fast in earth atmoshoere, but that is still slower than a vacuum, which does not contain any air or particles, theoretically.
For every day use in the kitchen or shop, traditional units are generally easier to use. Go down the pub and order 568 ml, mate. You can call 500 ml a metric pint, but then what's the purpose? Same with a metric pound ( 500 grams). What's a ninth of a meter? A ninth of a yard is four inches. Not quite as simple as saying 11.111.... cm, admittedly.
And whats an eighth of a yard? quite easy to say in cm... 12.5cm. Do you know why? because it's just 100/8, everybody with basic education can calculate that within seconds. Try to order a "Maß" in imperial units... in SI units it's just 1 liter. Also it is possible to change a pint to 500ml. Thats exactly what they did with the "Maß": en.wikipedia.org/wiki/Ma%C3%9F your arguments are invalid.
Good video! Entertaining and worth watching. I can't believe how many people can't get passed the fact that he isn't using the metric system. If it's even real, it's interesting regardless. I mean.. he's measuring the speed of light...
First of all, what is an oscilloscope? How did we measure how many frames it holds per sec? I do not want to measure the speed of light by a machine which I do not have any idea about. How can we measure speed of light from scratch?
Just know he is using it properly. I use one in my job. It's mainly used to measure (and view) frequencies. It is time based, so you can see how far apart peaks (or troughs) in micro or milli seconds. plus you can measure the amplitude of the signal.
@uclaphysicsvideo How would you measure the speed of light immediately as it leaves it leaves a medium such that the speed is still the same as if it were in that medium?
Can't you get a really long single timer with highest fps cameras running along the length? like a T shape on it's side? measure it going both directions
How did you measure both the mirror distances ? This crucial and you did not show it. Nanometers can throw the experiment off if you are talking nanoseconds.
To measure the speed of dark you have Darth Vader turn on the laser, run 30 feet and touch the mirror and run back again and turn off the laser. The speed of dark would be 60 ft divided by the amount of nano seconds the laser was on.
Which light speed are you measuring with your detector? When you observe the reflected light from mars that means you saw mars. Right? But, do you see the light as a wave? or do you see mars as a wave?are you able to measure that wave with your device (detector)? I mean when we say light speed we may need to answer the related question: which light? which light speed? Right?
This experiment doesnt take into account that the earth is moving through space, so if the speed of light is constant, it will move at different speeds relative to the earth on the way TO the mirror and back FROM the mirror. The only way to measure it is with sync clocks in different points which is also impossible because in order to sync them you need to know the speed of light. So there's no way to actually measure the speed of light, when you realize you need to know the speed of light to calculate the time dilation between your points of measurement. Einstein wrote this in the first page of his electromagnetism article.
So light travels a foot in a nanosecond. Navy Admiral Grace Hopper used to walk around with 30 cm (or 1 foot) chunks of wire and pass out "nanoseconds" to all and sundry. What a legend.
Does the lazer generate and transmit only light? What is light? which one is light? strong beam, light beam, medium beam, faint beam, very strong beam.....? thanks.
wait so why was the laser shot into the receiver with the no time delay or no extra distance used...i thought he was going to use that..... also i wish you had covered how to use the o scope with the receiver as well since it was a simple set up....that would have been useful
The Laser is storming the receiver and the oscilloscope forcing them to respond for the storm. But, there was/is light around the receiver and the oscilloscope, but they don't sense it, they don't respond for it. So, to measure light speed we need, we need an equipment which is at least made of light itself, which is impossible, impossible even if we create clocks or sensors made of light. Right? Thanks.
How can you tell the difference between the receivers reaction time vs light speed? Maybe the speed recorded is the limit of processing for the receiver.
My Question is, about the meaning of c. C (used in e=mc2) is supposedly the speed of light. Only, under the conditions of a vaccum. So, how can you measure that and get accurate results?
no its not. water for example: look up the video of a nuclear reactor shooting electrons through water at a speed greater than the speed of light in that medium.
@@fuahuahuatime5196 no man the speed of individual photons is always exactly c, the whole beam of light consisting of a lot of photons slows down because of interactions with the material it passes through
How doesn't the speed of electricity through the chosen conductor effect the accuracy of this experiment? Had that been factored into the official findings?
I know that we can measure the speed of light pretty well. One silly question: When you have two sensors hooked up to the same computer, the information can only travel so fast. Couldn’t you say that 1) there should be an error in the calculation due to how electricity is transferred - and 2) you couldn’t get the speed of light from a single device, because that device is running a single thread at once as well. I just, think there are a few logistical issues with this setup. Also, it’s not in a vacuum…
Then there was, "In 1676, the Danish astronomer Ole Roemer (1644-1710) became the first person to measure the speed of light. Roemer measured the speed of light by timing eclipses of Jupiter's moon Io. "French physicist Hippolyte Fizeau is credited with making the first non-astronomical measurement, in 1849, using a method that involved sending light through a rotating toothed wheel then reflecting it back with a mirror located a significant distance away. One of the first precise calculations of light’s velocity was made in the 1920s by American physicist Albert Michelson, who carried out his research in the mountains of Southern California using an eight-sided rotating mirror apparatus.
UnderMan UnderMan More like just about everything in our country measurement-wise is customary oriented? It would be a massive undertaking and would only cause confusion and unnecessary stress for a number of years following our theoretical switch over to metric.
For day-to-day uses, in the kitchen or carpentry shop, traditional units are incontrovertibly more convenient. Just about the only inherent advantage of metric units is representation in base 10 numerals. That's *really important* when you do calculations with tables of base 10 logarithms and slide rules. Do you know anyone like that? Your reaction to traditional units is conditioned by your familiarity with them. Americans have somewhat the same reaction to metric units. So metric units would be preferred by people whose labors consist of tedious laborious calculations, traditional units by people baking cakes or framing houses. I know you can do carpentry and cooking with with metric units, but it's like teaching a dog to walk on its hind legs. The wonder is not that it is done with difficulty, but that it is done at all. American scientists and engineers are perfectly capable of operating with either metric or useful units. We feel no need to impose laboratory units on our mothers in the kitchen, or at the hardware store or lumberyard. The impulse to do so is inherently totalitarian, redolent of the French Revolution. Before you lecture us about our backwardness, you ought to do something about that gawdawful sexagesimal system of time. Why not some rational enlightened time units? Why won't you save us from those vestiges or primitiveness, the second, the minute and the hour? And the Gregorian Calendar! Quelle horreur! That relic of superstition and Eurocentricism! We need a *rational* international standard of time! Appoint a UN commission! One that makes the day a simple fraction of the year! 365.2425 days in the year, indeed! A year should be a kiloday, 1000 days long! Time should be in units of the day! The decaday (2.4 traditional hours) will be the natural unit of length of time of human activity. The centiday (864 seconds - 14.4 minutes) is a most natural and useful measure of time! Oh thinK of the *improvements* in the arts and sciences when mankind is no longer shackled to those superannuated traditional units of time! A boon to education and the economy! Why don't you stupid and unenlightened people just DO WHAT I AM TELLING TO YOU TO DO FOR YOUR OWN GOOD!!!!!
C=d/t the distance corresponds to the time measured and then you get the speed of light. The equipment bye itself makes all the time measurements with hi precision this makes the experiment easier.
and the experiment is complete trash and doesnt prove that light moves bc is dont move , the only situation where light moves and has speed its when a car that has light moves so that light would move with thats the only way speed of light could make sense other than that its jus made up by man
@@qdpqbp As we belief that the earth is moving and rotating, the laser, mirror and target are also moving. Therefore: the path to the mirror is not the same path away from the mirror.
@@qdpqbp OK so imagine a record player going around. But it is big, and you can look at it frim the top. Place a penny on the turntable and at some speed the penny will slide off the turntable. FROM the perspective of being on the turntable the penny goes straight. However: looking from above, independent of the turntable we can see the path of the penny is a curve. See th-cam.com/video/WdcfWf07UIg/w-d-xo.html . So gravity and rotation affect light see gravitational lensing. If the penny bounced back that would also be a different path.
Holong does it take fir the issciliscope to sense light and to create frame and to display pixeles...etc and how long does it take for the receivers and oscilloscope to convert the lught to electrical. .etc?Thanks.
+Jonas Madsen Rogne Yes, that's why the Real Big-bang physicists stick with 'C', otherwise the whole concept, especially Relativity becomes so obviously ridiculous, that even Pixy-dust can't fix. Notice how the key words "time delay" is repeated? Just like in nature documentaries the hypnotic: "Science, .." followed by "Sixty billion years ago, 120 billion years ago, Dinosaurs," and of course the famous movie star "T-Rex."If time dilation was real, then a rocket taking off from earth, from the rocket perspective the earth is moving away from the rocket, right? So who is 'time dilating'? From the rockets perspective when the astronaut returns 20 years from now, it is he who has aged while the people on earth has aged far less because of the earth speeding away from the ship. From the earths perspective, it is the rocket that has distanced away from them, so the guy in the rocket aged less.In reality, neither has aged less or aged more. They all aged 20 years. It is all BS, so is the 'speed of light', a necessary delusion to keep the confusion rolling.
+Odon Sabo I'm sorry you dropped out of school so early and never took enough physics classes. In your rocket example, the people on the extremely fast rocket would have aged slightly less compared to those on earth when they meet if the rocket turns around and returns. Also the numbers you are throwing out are way too big, the earth has only been around for 4-5 billion years.
+Jonas Madsen Rogne Thank you Jonas, I was just summarizing things being un-respectful of people with your caliber of intelligence, .. and I am truly sorry. 300 or more years ago they gave a pretty close to what we have today answer to how fast light travels in a vacuum, so I should have mentioned the value of the energy density of the vacuum of space, or the cosmological constant. As you well know light can have very different speeds, depending what medium it is traveling through. They claim they have stopped light in a frozen saline solution, so understanding the energy density of space is extremely important, so is the proper use of mathematics. They say the cosmological constant has the same effect as an intrinsic energy density of the vacuum, ρvac (and an associated pressure). In this context, it is commonly moved onto the right-hand side of the equation, and defined with a proportionality factor of 8π: Λ = 8πρvac, where unit conventions of general relativity are used (otherwise factors of G and c would also appear, i.e. Λ = 8π (G/c2) ρvac = κ ρvac, where κ is Einstein's constant). It is common to quote values of energy density directly, though still using the name "cosmological constant", with convention 8π G = 1. (In fact, the true dimension of Λ is a length-2 and it has the value of ~1 10-52 m-2 or in reduced Planck units : ~3 10-122, calculated with the best present values of ΩΛ = 0.6911 ± 0.0062 and Ho = 67.74 ± 0.46 km/s / Mpc = 2.195 ± 0.015 10-18 s-1. As for Earth being around for 4-5 billion years old, .. well now who is throwing numbers around? Is it 4 BILLION years, or is it 5 BILLION years, because if you consider the Evolution of monkey-man to man-monkey (Homo erectus) 1.8 to 1.3 million years, .. that's a dumb monkey swinging from the trees to us debating reasoning intelligent clothes wearing people who invent gods for religious entertainment. 1 BILLION year difference is huge in evolutionary terms, cause you have to fill in those gaps. As for my brief rocket example, take two objects in space, Earth and a rocket. You got it? Now they are moving apart, or separating at near light speeds, now which one is dilating? Think this through before you answer!? Thank you my friend.
I said the earth was 4-5 billion years old, because I didn't bother to look up a more precise number. The range I gave was correct though, and not random numbers like the one you used. A quick check would tell you that our best measurements currently places it at 4.54 ± 0.05 billion years (4.54 × 109 years ± 1%). Seeing as it didn't form instantaniously overnight but gradually from over a longer period of accretion, I imagine a much more precise number would be hard to find... Anyway, your rocket example is well known. Relativity can get a bit hard to wrap your head around (as it's not intuitive "common sense") so google it if you want more thorough explanations and maths. If the tocket leaves earth at a _constant_ near-light speed (no acceleration/turning - just a straight path), and the observer on the rocket and the one on earth look at each others clocks (through some super-telescopes) they would both see the other observer's clock running slower than their own. It would be perfectly symmetrical (if compensating for the time delay/doppler effect of the light traveling between the two). Now, what happens when we accelerate the rocket to turn it around and switch to another inertial frame and return it to earth? Read more: en.wikipedia.org/wiki/Twin_paradox
Has anyone tried measuring speed of light in one direction? Like... forward, without reflecting back? In addition to that, has anyone tried measuring pointing both parallel to and perpendicular from the earth surface (in one direction)? I know there are some "relativistic effects" which make it implausible to transport the sensor while keeping it in the same point of reference... yet still - has anyone tried it in practice, and what was the outcome, in practice?
@@syedviqar1 yes, to a point... but also interested if light speed will be measured to go faster upward-downward. Just that... E=mc2 is the equation for all waves. Like... sound travels in metal and air at the speed C, where m is density, E is stiffness... stiffness, in material science - is kinetic energy stored in deformed "spring". So... it is funny. I'm interested if stiffness of space is changing with gravitational field...
Speed of light is not measurable. Light speed is infinite because removing the source of light results in immediate removal of the light. from any where ,it has reached, in a moment. that means light illuminates just a certain area , the amount area covered depending on the strength of the light generated from the light source. right? Thanks.
But sir I have a doubt :How can we confirm that the speed of light is the same when it is reflected back? Because the gravitational force can be varying on earth because of its geometrical design And if it is so then what we are seeing is that the time taken for light to reach mirror to be (suppose) 20 seconds while the time taken for light to travel back to the detector is done in an instant and what we will see is 20 seconds .....yes it is confusing but consider in space we know when light travels from One end of the bottom curve of a 🌎 planet to another then it would take more distance and less time than that of speed traveling straight line in space from point A to B ....so in both cases “C” or speed is constant and only time and distance adjusts itself and since speed is said to be “same everywhere” the same would apply to earths gravitational force ....I maybe stupid I thinking so cause I’m only 15 and I know the person reading this would not understand anything but I wish to post this somewhere hoping something useful would be made of my thinking
If you want to introduce the geometry of spacetime you need to study general relativity which is not the case here, the demonstration here is assuming flat spacetime (but it is still postulated that the speed of light is constant to any observer on any curved spacetime)
1) you use red laser, different speed 2) there is no vacuum 3) time delay of you machins to analyze the signal 4) how you measured the 30 feet? 5) it's not so simple 60/60*30feet
"to measure speed of light" Which light? there is light with out the laser light in your room, and you see it. Your oscilloscope/receiver is operated by some voltage level of signal, light. If it is not laser light it doesn't sense (see) the room light. But, Your eye doesn't need that voltage strength, it can see the room light. So which light are you considering and measuring its speed? Thanks.
+Asrat Mengesha Exactly, only you shouldn't ask questions like that because you know how religionists are, they get offended right away and want to cut off your head! As you can see ammy246810's response; "what dribble is this?" lol.
1 foot is the length in a billionth of a second i've known for a while, but this blew my mind right here! - another thing i noticed is that a signal frequency of 299972458 MHZ has a wave length of exactly 1 meter. woah.
![[TH] VCT Masters Shanghai Playoffs DAY 2 // PRX vs G2 | EDG vs TH](http://i.ytimg.com/vi/T5j2XVcDFs0/mqdefault.jpg)
FEET PER SECOND???
BLASPHEMY!!!
WHY NOT BANANA/ROCK?!
Nano second
Why not Pie/Cake
@@rupeshart9480 Bank Banana
1,802,617,499,785 , and 2 and 1/2 chains per fortnight. Much simpler and more intuitive.
why feet per second why not leg per second
iI'S "FOOTS" OR "FOOTSIES PURR SUCKENT"!
hahha
halfmoon26 The question is simply a matter of relativity. How many Shlongs per second does light travel when perceived by whom? It certainly isn't a constant!
Why not Smoots per fortnight? en.wikipedia.org/wiki/List_of_humorous_units_of_measurement#Smoot
Lol🤣👀
A scientist who uses imperial system LOL
Imperial.. Used by: The Romans, British and Americans...... The most inventive nations/empires in the world.
Not the most practical system for Maths and Physics lol
I know right?!! That lab coat has got to be fake.
I couldn't belive it myself and lost interest in the explanation.
Obviously, the video is intended for (very) non-science people not for the lads and ladies at CalTech!
For all of you saying this isn't a good experiment because he's not in vacuum, his calculation is actually only off in a true vacuum by about 1.6429% considering the speed of light in a vacuum is exactly 299,792,458 m/s. Not a huge margin if you don't need to be extremely precise, which usually isn't needed in simple calculations. 60ft/60ns a really good approximation, aside from the fact that you're using feet.
zeaga15 good enough to build antennas
doesnt the speed of light stays constant through all mediums 🤔
Per-haps this is a "Demonstration" and not an "experiment". One shows what we know and the other discovers something.
Nerd but I agree
@@drfazailzia8830 no, light slows down a lot in water and ice. It travels quite fast in earth atmoshoere, but that is still slower than a vacuum, which does not contain any air or particles, theoretically.
Clear and informative explanation thank you!
Great demonstration. That's the kind of teaching (clear & demonstrative) I need.
My class (here in the United Kingdom) think you are amazing! We would like to request a video or two about capacitors please.
Only time I've ever seen imperial come out simpler o_O
For every day use in the kitchen or shop, traditional units are generally easier to use. Go down the pub and order 568 ml, mate. You can call 500 ml a metric pint, but then what's the purpose? Same with a metric pound ( 500 grams). What's a ninth of a meter? A ninth of a yard is four inches. Not quite as simple as saying 11.111.... cm, admittedly.
And whats an eighth of a yard? quite easy to say in cm... 12.5cm. Do you know why? because it's just 100/8, everybody with basic education can calculate that within seconds.
Try to order a "Maß" in imperial units... in SI units it's just 1 liter. Also it is possible to change a pint to 500ml. Thats exactly what they did with the "Maß": en.wikipedia.org/wiki/Ma%C3%9F
your arguments are invalid.
@@jimdecamp7204 measuring the speed of light is not "every day use"
@@Miguel_Noether Whoosh.
Quite good one...!!
Good video! Entertaining and worth watching. I can't believe how many people can't get passed the fact that he isn't using the metric system. If it's even real, it's interesting regardless. I mean.. he's measuring the speed of light...
awesome explanation !!!
First of all, what is an oscilloscope? How did we measure how many frames it holds per sec? I do not want to measure the speed of light by a machine which I do not have any idea about. How can we measure speed of light from scratch?
Good point. Not understanding what the tool is or does, leads to potential fraud.
Just know he is using it properly. I use one in my job. It's mainly used to measure (and view) frequencies. It is time based, so you can see how far apart peaks (or troughs) in micro or milli seconds. plus you can measure the amplitude of the signal.
Saby Mondal u can't our senses are not strong enough
Saby Mondal
i would like to work with you on speed of light
need two mountains far apart and two guys with lanterns and radios - LOL!
Actually the foot per nanosecond definition is very convenient when doing anything involving signal propagation.
Muchas Gracias Senior
I love how he converted to metric system at the end
Now do that without a mirror (two receivers), and with the laser in motion relative to the receivers. Will the speed really be constant?
yes and the reason why has been explained by einstein in his theory of special relativity
Speed is undefined in non inertial frames.
İsn't it moving with earth's rotation
I am from India and i am big fan of your practical teaching
How do we know the O-scope was accurate? What was it calibrated to?
How would I know if the response time of the electrical components weren't affecting my measurements were I to do this myself?
@uclaphysicsvideo How would you measure the speed of light immediately as it leaves it leaves a medium such that the speed is still the same as if it were in that medium?
Please make another video on this topic
cool. i was always curious about that :)
Thanks. Nice explanation
Could you redo this experiment with water and glass etc? And is light carried with flowing water?
Thanks!
I have used nano seconds per foot as a unit in electronics because a lot of psb layout uses lengths in decimalised inches.
jgt
Great
How do you know the distance is EXACTLY. Did you measure it PRECISELY? How were you able to measure it so pecicely?
Can't you get a really long single timer with highest fps cameras running along the length? like a T shape on it's side? measure it going both directions
thanks, you answered this question which i had in my mind since weeks in just 2 minutes... O: well done my friend ! THX
Perfect - experimental, empirical.
Will you get the same result with a gold mirror
How did you measure both the mirror distances ?
This crucial and you did not show it.
Nanometers can throw the experiment off if you are talking nanoseconds.
Champion presentation.
Thanks for serving to my curiousity
Good video
How do you do it without or before a 100 MHz. oscilloscope, though?
To measure the speed of dark you have Darth Vader turn on the laser, run 30 feet and touch the mirror and run back again and turn off the laser. The speed of dark would be 60 ft divided by the amount of nano seconds the laser was on.
ohh ok and how do we measuere the speed of dumbness
top 10 unsatisfying videos of all time. this one would make it to that list lol
Which light speed are you measuring with your detector?
When you observe the reflected light from mars that means you saw mars. Right?
But, do you see the light as a wave? or do you see mars as a wave?are you able to measure that wave with your device (detector)?
I mean when we say light speed we may need to answer the related question: which light? which light speed? Right?
This experiment doesnt take into account that the earth is moving through space, so if the speed of light is constant, it will move at different speeds relative to the earth on the way TO the mirror and back FROM the mirror. The only way to measure it is with sync clocks in different points which is also impossible because in order to sync them you need to know the speed of light. So there's no way to actually measure the speed of light, when you realize you need to know the speed of light to calculate the time dilation between your points of measurement. Einstein wrote this in the first page of his electromagnetism article.
So light travels a foot in a nanosecond. Navy Admiral Grace Hopper used to walk around with 30 cm (or 1 foot) chunks of wire and pass out "nanoseconds" to all and sundry. What a legend.
i think it depends on the health of the light. if its been working out at the gym it will travel faster than if its been watching TH-cam all day.
Does the lazer generate and transmit only light?
What is light? which one is light? strong beam, light beam, medium beam, faint beam, very strong beam.....? thanks.
wait so why was the laser shot into the receiver with the no time delay or no extra distance used...i thought he was going to use that..... also i wish you had covered how to use the o scope with the receiver as well since it was a simple set up....that would have been useful
You can observe the farthest star, but your detector doesn't detect that light. Right?
Thanks.
What did you use for the receiver?
The Laser is storming the receiver and the oscilloscope forcing them to respond for the storm. But, there was/is light around the receiver and the oscilloscope, but they don't sense it, they don't respond for it. So, to measure light speed we need, we need an equipment which is at least made of light itself, which is impossible, impossible even if we create clocks or sensors made of light. Right?
Thanks.
gt
Thank you sir.
Does the receiver sense at speed of much much greater than light speed?
Can anyone tell me how I set up this experiment and what all these tools are called? I need it for school
This shows feet is soooo much better than meters because it's directly related to the speed of light (1 feet / nanosecond) beautiful.
Can we measure the speed of light which gets reflected from a mirror.
Wouldnt signals cause a massive delay since it itself isnt light? I need to understand the device itself
How can you tell the difference between the receivers reaction time vs light speed? Maybe the speed recorded is the limit of processing for the receiver.
My Question is, about the meaning of c. C (used in e=mc2) is supposedly the speed of light. Only, under the conditions of a vaccum. So, how can you measure that and get accurate results?
speed of light is same in all mediums but light travels more distance in denser medium due to refrection of atoms and molecules
no its not. water for example: look up the video of a nuclear reactor shooting electrons through water at a speed greater than the speed of light in that medium.
+Catherine Macasieb the speed of light will still be faster than the speed of electrons in the same medium. light has no mass. electrons do.
8
thank you
So the laser is shot at both mirrors at the same time?
I want to see more from this channel but I think deeper explanations of equipment and methods are needed, see the other comments about this.
Serious question here: Doesn't the speed of light vary depending on the atmosphere? Vacuum? No Vacuum?
The speed of light changes depending on the material it's passing through. But the fastest it can go is the speed it travels in a vacuum.
mapoff and as the light returns to the previous medium it resumes its speed prior to passing through another medium.
@@fuahuahuatime5196 no man the speed of individual photons is always exactly c, the whole beam of light consisting of a lot of photons slows down because of interactions with the material it passes through
How doesn't the speed of electricity through the chosen conductor effect the accuracy of this experiment? Had that been factored into the official findings?
Because the electric current does not travel at c, the electric field through the wires does
First time I've seen foot used together with speed of light
i never knew chandler was so smart
what if the electron flow is not a constant and it doesnt travel at speed of lite?
What about the delay incurred by the laser light bouncing off the mirror?
More impressive -we’re the guys that figured it without the equipment!!
I know that we can measure the speed of light pretty well.
One silly question:
When you have two sensors hooked up to the same computer, the information can only travel so fast. Couldn’t you say that 1) there should be an error in the calculation due to how electricity is transferred - and 2) you couldn’t get the speed of light from a single device, because that device is running a single thread at once as well.
I just, think there are a few logistical issues with this setup. Also, it’s not in a vacuum…
Then there was, "In 1676, the Danish astronomer Ole Roemer (1644-1710) became the first person to measure the speed of light. Roemer measured the speed of light by timing eclipses of Jupiter's moon Io. "French physicist Hippolyte Fizeau is credited with making the first non-astronomical measurement, in 1849, using a method that involved sending light through a rotating toothed wheel then reflecting it back with a mirror located a significant distance away. One of the first precise calculations of light’s velocity was made in the 1920s by American physicist Albert Michelson, who carried out his research in the mountains of Southern California using an eight-sided rotating mirror apparatus.
Which language is used to buy you in this video
Old British Empire "feet"? Don't Americans understand modern measurements in a scientific context???
i dont know why he used feet. that's unusual
then he changed to m/s.
Americans need to get with the the modern world. They're too pompous for their own good.
UnderMan UnderMan More like just about everything in our country measurement-wise is customary oriented? It would be a massive undertaking and would only cause confusion and unnecessary stress for a number of years following our theoretical switch over to metric.
Tony Souter Canada changed to the metric system decades ago. It's not as big a leap as you make it out to be.
For day-to-day uses, in the kitchen or carpentry shop, traditional units are incontrovertibly more convenient. Just about the only inherent advantage of metric units is representation in base 10 numerals. That's *really important* when you do calculations with tables of base 10 logarithms and slide rules. Do you know anyone like that?
Your reaction to traditional units is conditioned by your familiarity with them. Americans have somewhat the same reaction to metric units.
So metric units would be preferred by people whose labors consist of tedious laborious calculations, traditional units by people baking cakes or framing houses. I know you can do carpentry and cooking with with metric units, but it's like teaching a dog to walk on its hind legs. The wonder is not that it is done with difficulty, but that it is done at all.
American scientists and engineers are perfectly capable of operating with either metric or useful units. We feel no need to impose laboratory units on our mothers in the kitchen, or at the hardware store or lumberyard. The impulse to do so is inherently totalitarian, redolent of the French Revolution.
Before you lecture us about our backwardness, you ought to do something about that gawdawful sexagesimal system of time. Why not some rational enlightened time units? Why won't you save us from those vestiges or primitiveness, the second, the minute and the hour? And the Gregorian Calendar! Quelle horreur! That relic of superstition and Eurocentricism! We need a *rational* international standard of time! Appoint a UN commission! One that makes the day a simple fraction of the year! 365.2425 days in the year, indeed! A year should be a kiloday, 1000 days long! Time should be in units of the day! The decaday (2.4 traditional hours) will be the natural unit of length of time of human activity. The centiday (864 seconds - 14.4 minutes) is a most natural and useful measure of time! Oh thinK of the *improvements* in the arts and sciences when mankind is no longer shackled to those superannuated traditional units of time! A boon to education and the economy! Why don't you stupid and unenlightened people just DO WHAT I AM TELLING TO YOU TO DO FOR YOUR OWN GOOD!!!!!
C=d/t the distance corresponds to the time measured and then you get the speed of light. The equipment bye itself makes all the time measurements with hi precision this makes the experiment easier.
and the experiment is complete trash and doesnt prove that light moves bc is dont move , the only situation where light moves and has speed its when a car that has light moves so that light would move with thats the only way speed of light could make sense other than that its jus made up by man
The pain he suffered to demonstrate that Lazer. Ouch!
thanks a lot ............this is my tomorrow's experiment
Can you do this one way or does it have to go there and back?
Impossible
Feet? Heck no.
"Common measurement for physicists."
How do you prove light travels at the same speed to and from the mirror?
@@qdpqbp As we belief that the earth is moving and rotating, the laser, mirror and target are also moving. Therefore: the path to the mirror is not the same path away from the mirror.
@@qdpqbp OK so imagine a record player going around. But it is big, and you can look at it frim the top. Place a penny on the turntable and at some speed the penny will slide off the turntable. FROM the perspective of being on the turntable the penny goes straight. However: looking from above, independent of the turntable we can see the path of the penny is a curve. See th-cam.com/video/WdcfWf07UIg/w-d-xo.html . So gravity and rotation affect light see gravitational lensing. If the penny bounced back that would also be a different path.
Holong does it take fir the issciliscope to sense light and to create frame and to display pixeles...etc and how long does it take for the receivers and oscilloscope to convert the lught to electrical. .etc?Thanks.
+Asrat Mengesha Luckily that is completely irrelevant for this experiment setup.
+Jonas Madsen Rogne Yes, that's why the Real Big-bang physicists stick with 'C', otherwise the whole concept, especially Relativity becomes so obviously ridiculous, that even Pixy-dust can't fix. Notice how the key words "time delay" is repeated? Just like in nature documentaries the hypnotic: "Science, .." followed by "Sixty billion years ago, 120 billion years ago, Dinosaurs," and of course the famous movie star "T-Rex."If time dilation was real, then a rocket taking off from earth, from the rocket perspective the earth is moving away from the rocket, right? So who is 'time dilating'? From the rockets perspective when the astronaut returns 20 years from now, it is he who has aged while the people on earth has aged far less because of the earth speeding away from the ship. From the earths perspective, it is the rocket that has distanced away from them, so the guy in the rocket aged less.In reality, neither has aged less or aged more. They all aged 20 years. It is all BS, so is the 'speed of light', a necessary delusion to keep the confusion rolling.
+Odon Sabo I'm sorry you dropped out of school so early and never took enough physics classes. In your rocket example, the people on the extremely fast rocket would have aged slightly less compared to those on earth when they meet if the rocket turns around and returns. Also the numbers you are throwing out are way too big, the earth has only been around for 4-5 billion years.
+Jonas Madsen Rogne Thank you Jonas, I was just summarizing things being un-respectful of people with your caliber of intelligence, .. and I am truly sorry. 300 or more years ago they gave a pretty close to what we have today answer to how fast light travels in a vacuum, so I should have mentioned the value of the energy density of the vacuum of space, or the cosmological constant. As you well know light can have very different speeds, depending what medium it is traveling through. They claim they have stopped light in a frozen saline solution, so understanding the energy density of space is extremely important, so is the proper use of mathematics. They say the cosmological constant has the same effect as an intrinsic energy density of the vacuum, ρvac (and an associated pressure). In this context, it is commonly moved onto the right-hand side of the equation, and defined with a proportionality factor of 8π: Λ = 8πρvac, where unit conventions of general relativity are used (otherwise factors of G and c would also appear, i.e. Λ = 8π (G/c2) ρvac = κ ρvac, where κ is Einstein's constant). It is common to quote values of energy density directly, though still using the name "cosmological constant", with convention 8π G = 1. (In fact, the true dimension of Λ is a length-2 and it has the value of ~1 10-52 m-2 or in reduced Planck units : ~3 10-122, calculated with the best present values of ΩΛ = 0.6911 ± 0.0062 and Ho = 67.74 ± 0.46 km/s / Mpc = 2.195 ± 0.015 10-18 s-1. As for Earth being around for 4-5 billion years old, .. well now who is throwing numbers around? Is it 4 BILLION years, or is it 5 BILLION years, because if you consider the Evolution of monkey-man to man-monkey (Homo erectus) 1.8 to 1.3 million years, .. that's a dumb monkey swinging from the trees to us debating reasoning intelligent clothes wearing people who invent gods for religious entertainment. 1 BILLION year difference is huge in evolutionary terms, cause you have to fill in those gaps. As for my brief rocket example, take two objects in space, Earth and a rocket. You got it? Now they are moving apart, or separating at near light speeds, now which one is dilating? Think this through before you answer!? Thank you my friend.
I said the earth was 4-5 billion years old, because I didn't bother to look up a more precise number. The range I gave was correct though, and not random numbers like the one you used. A quick check would tell you that our best measurements currently places it at 4.54 ± 0.05 billion years (4.54 × 109 years ± 1%). Seeing as it didn't form instantaniously overnight but gradually from over a longer period of accretion, I imagine a much more precise number would be hard to find...
Anyway, your rocket example is well known. Relativity can get a bit hard to wrap your head around (as it's not intuitive "common sense") so google it if you want more thorough explanations and maths. If the tocket leaves earth at a _constant_ near-light speed (no acceleration/turning - just a straight path), and the observer on the rocket and the one on earth look at each others clocks (through some super-telescopes) they would both see the other observer's clock running slower than their own. It would be perfectly symmetrical (if compensating for the time delay/doppler effect of the light traveling between the two). Now, what happens when we accelerate the rocket to turn it around and switch to another inertial frame and return it to earth? Read more:
en.wikipedia.org/wiki/Twin_paradox
What if the Delay is caused by the mirror itself?
Nice Experiment yet why do you measure distance in feet and hove result in metre/ sec ?
3 X 10^8 m/s
"ouch" 🤣
If two torches were pointed at each other, then turned on...is the collision point twice the speed of light?
Yes, but there's nothing physical actually traveling twice the speed of light, so it's not relevant
ISAAC NEWTON : HOLD MY BEER.
What is the Bandwith of your scope, 200Mhz ?
*
* *** ****** ****** ** ***** ?
Has anyone tried measuring speed of light in one direction? Like... forward, without reflecting back?
In addition to that, has anyone tried measuring pointing both parallel to and perpendicular from the earth surface (in one direction)?
I know there are some "relativistic effects" which make it implausible to transport the sensor while keeping it in the same point of reference... yet still - has anyone tried it in practice, and what was the outcome, in practice?
th-cam.com/video/pTn6Ewhb27k/w-d-xo.html
Just watched this and read your comment
Veritasium fan?
@@syedviqar1 yes, to a point... but also interested if light speed will be measured to go faster upward-downward.
Just that... E=mc2 is the equation for all waves. Like... sound travels in metal and air at the speed C, where m is density, E is stiffness... stiffness, in material science - is kinetic energy stored in deformed "spring".
So... it is funny. I'm interested if stiffness of space is changing with gravitational field...
Could u plz use metric system more often
no
Speed of light is not measurable. Light speed is infinite because removing the source of light results in immediate removal of the light. from any where ,it has reached, in a moment. that means light illuminates just a certain area , the amount area covered depending on the strength of the light generated from the light source. right?
Thanks.
I am Indian and very interesting and understanding video
But sir I have a doubt :How can we confirm that the speed of light is the same when it is reflected back? Because the gravitational force can be varying on earth because of its geometrical design And if it is so then what we are seeing is that the time taken for light to reach mirror to be (suppose) 20 seconds while the time taken for light to travel back to the detector is done in an instant and what we will see is 20 seconds .....yes it is confusing but consider in space we know when light travels from One end of the bottom curve of a 🌎 planet to another then it would take more distance and less time than that of speed traveling straight line in space from point A to B ....so in both cases “C” or speed is constant and only time and distance adjusts itself and since speed is said to be “same everywhere” the same would apply to earths gravitational force ....I maybe stupid I thinking so cause I’m only 15 and I know the person reading this would not understand anything but I wish to post this somewhere hoping something useful would be made of my thinking
If you want to introduce the geometry of spacetime you need to study general relativity which is not the case here, the demonstration here is assuming flat spacetime (but it is still postulated that the speed of light is constant to any observer on any curved spacetime)
1) you use red laser, different speed
2) there is no vacuum
3) time delay of you machins to analyze the signal
4) how you measured the 30 feet?
5) it's not so simple 60/60*30feet
what's the receiver name?
"to measure speed of light"
Which light? there is light with out the laser light in your room, and you see it. Your oscilloscope/receiver is operated by some voltage level of signal, light. If it is not laser light it doesn't sense (see) the room light. But, Your eye doesn't need that voltage strength, it can see the room light. So which light are you considering and measuring its speed?
Thanks.
Asrat Mengesha What dribble is this? He is measuring the speed of the light leaving the laser, and going to the detector. Simplez.
+Asrat Mengesha Exactly, only you shouldn't ask questions like that because you know how religionists are, they get offended right away and want to cut off your head! As you can see ammy246810's response; "what dribble is this?" lol.
1 foot is the length in a billionth of a second i've known for a while, but this blew my mind right here! - another thing i noticed is that a signal frequency of 299972458 MHZ has a wave length of exactly 1 meter. woah.
A scientist using feet. Mericans.
Bah! Lasers.
How did Maxwell & Co. do it?
… and what about the reference frame?
WooW
I thought they used a spinning turntable full of prisms that the laser pointed at?
But you did not count the 3 feet to the reciever, doesn't that mean you subtract 3 feet from 30 to get an accurate distance?
what a funny way to measure distance in feet! the unit is meter.
But is speed of light same from and towards the source
can we use laser to measure the speed of light?
Why not?