How to Measure the Speed of Light in your kitchen! (Waves, Physics)

[@alysterbenedict]

The most talented teacher o😍😍😍n earth

[@PhysicsMadeEasy]

Wow thanks!

[@SHARHANMOHAMMEDALHASSAN]

This is over the moon with excellence. Thank you. Just made me smiling

[@PhysicsMadeEasy]

You are welcome Sharhan. I am glad a physics lesson made you smile! The Universe does have a sense of Humor ;-)

[@amrimoussa2606]

masterpiece

[@PhysicsMadeEasy]

Thank you :-)

[@gyanendrasingh4471]

This is so fantastic. What a way to explain so many important concepts and also arrive at the result using those concepts by using everyday stuff(no I don't eat cheese everyday). Brilliant stuff

[@PhysicsMadeEasy]

Thank you Gyanendra! I am glad you appreciated the approach. I actually enjoyed very much doing this one, as it provided many opportunities to explain very interesting and important notions in physics. and also, it was fun :-)!

[@gyanendrasingh4471]

@@PhysicsMadeEasy Indeed it must have been. In the easiest way possible you explained application of law of Physics in reality. You definitely deserve subscribers equal to the magnitude of speed of light 😀

[@luzbuensuceso2916]

What a great way to teach the wave equation❤

[@PhysicsMadeEasy]

And it was a lot fun to teach it with that approach :-) I was quite amazed of getting a result so close to the real thing haha!

[@venujohn9362]

Great sir......👏👏👏👏

[@anonymous88897]

🙏🙏One of the best physics teacher on earth.🙏🙏 Thank u for providing knowledge free of cost.😊 Looking forward for ur upcoming intresting videos. Thank u.

[@PhysicsMadeEasy]

You are most welcome Vinit! And thanks for the kind words. I am glad you enjoy my work.

[@tabugboonyedika6974]

I really enjoyed it sir. Thanks and God bless u sir 😘😘😍😍😍

[@spencerwenzel7381]

Perfect, my physics class was asking me yesterday how they measure the speed of light in modern times. We will do so with cheese now on Monday.

[@PhysicsMadeEasy]

haha! How did it go?

[@spencerwenzel7381]

@@PhysicsMadeEasy Excellent! Next time, I will get larger slices of cheese but a few groups were within 2% of the accepted value. Your channel is a hidden gem I am glad I found, excellent videos. Your visualization of polar light using an oven rack is brilliant. Keep up the good work!

[@ArifKhan-tj2ez]

Really pretty beautiful.... Beauty of Physics= Understanding the Nature.

[@PhysicsMadeEasy]

Yes, Physics is full of symmetries, it's like a painting where all pieces come together. (the periods I prefer to teach in the life of a student is when the student already knows quite a few things and I make him realize how everything fits together in the end...)

[@zeyadramadan8759]

Really amazing.

[@PhysicsMadeEasy]

Thank you

[@nowthenad3286]

You are making me want to be a physics teacher.

[@PhysicsMadeEasy]

Go for it! It's a lot of fun!

[@jeonjungkook6584]

Thanks it helped me alot 😊🌺

[@PhysicsMadeEasy]

You are welcome Jeon. I am glad my work helped.

[@conradmendes5583]

Good video. Concept well explained 👍

[@PhysicsMadeEasy]

Thank you Conrad

[@gyanendrasingh4471]

Fantastico You deserve subscribers = the magnitude of speed of light. And more

[@PhysicsMadeEasy]

Merci Gyanendra, For the magnitude of the speed of light, are you talking in km/s or m/s ;-)?

[@gyanendrasingh4471]

@@PhysicsMadeEasy haa haa km/s sounds little impractical so let's stick to m/s and much more than that

[@PhysicsMadeEasy]

@@gyanendrasingh4471 🤣🤣🤣

[@beyon-limits]

Super nice work Mr Edouard, & we hope you do a quick review next time if you want to use math because we understand the phenomena, but the math makes it a little bit difficult, but anyway we really enjoyed it & thank you.

[@PhysicsMadeEasy]

Hello Ayoub, the only maths you need is actually: v = f x lambda. Maybe what I did in the end confused you a little: when you measure experimentally something, you need to know if your measurement is meaningful, so you need to define an interval centered around your experimental value that defines where the real result is... Then you need to see how this uncertainty affects the value of the quantity you calculate from your experimental value. This is called propagating the uncertainties (or error). After reading your comment, I just put this topic on the list of potential videos to come!

[@surendrakverma555]

Very good 🙏🙏🙏🙏

[@PhysicsMadeEasy]

I saw you viewed many of my videos. I hope you enjoyed them, thanks for exploring the world of Physics Made Easy!

[@stevewassailing]

Great demonstration! I enjoyed the simple analogue...but...how did they measure the Hz of the microwave? A long baguette?

[@PhysicsMadeEasy]

Thanks. The frequency of the microwaves is set by the manufacturer. it is probably set to the natural frequency of an internal oscillation of the water molecule (to optimise heating food).

[@ButchNews]

Neat. I saw a video, previously, where a guy put a sheet of paper covered with a dust into a micro wave to find the standing waves.

[@PhysicsMadeEasy]

I'm curious, do you have the link to that video?

[@ButchNews]

@@PhysicsMadeEasy I don't think I do. If I think of how to find it I'll let you know. I'm looking at Standing Wave research... i.e. Black Holes are standing waves (Russians beat me to that idea) and rings around planets are standing waves (Nasa beat me to that one but they don't see why it's so extra special yet... I'm into motion physics.)

[@ButchNews]

@@PhysicsMadeEasy I don't but I'll let you know if I find it again.

[@ButchNews]

@@PhysicsMadeEasy I only remember I was researching Standing Waves... one of my pet things to think about.

[@PhysicsMadeEasy]

​@@ButchNews Hi Butch, "rings around planets are standing waves". Yes, I knew that too and find it really cool. Be careful though, remain precise: rings are not standing waves, but their motion is... You can see each particle in the ring as oscillating, and interacting with their neighbours. the fact that it is a closed system (like a looped rope), imposes conditions for the existence of the resulting waves. Hence only harmonics related to the perimeter of the ring can exists... Oscillations will always occur when nature searches for an equilibrium following an interactions. Even the orbits of the planets of stellar systems, can be seen as particles interacting with each other (by gravity this time), and end up in harmonic synchronisation. The universe is waves… and as soon as you have rules or symmetries to follow, standing waves are just around the corner 😊.

[@evan.5967]

Sir, can you do a full playlist on electriicty: like volts, amps, resistance and building from there, doing more complex topic? I am beginner on electricity and I love your explanations you are best!

[@PhysicsMadeEasy]

Hi Evan, thank you. You are asking for a full course lol! Actually, I have published a few courses here: www.udemy.com/user/edouard-reny/ One of them is about electric fields but it stays on the basics (The fundamentals you need to enrol in an electrical science course effortlessly). And feel free to explore the channel: there is actually a playlist on electricity, but there is no teaching plan behind it, like a course would have. kzbin.info/aero/PLU0ETLdKNmc5UTL-_71rwUt1uUQra2-eC

[@PhysicsMadeEasy]

Oh, and I saw your other comment in my notifications. Yes, there has been a pause in me posting new videos, because of (positive) personal events happening that are requiring a lot of my time, and are limiting my access to my main computer (the one powerful enough to handle the video edition). And that should continue for maybe a few more months. Yet, it's been a couple of weeks where a little stability / rest combines with a full access to my things, so I had the opportunity to produce a few videos, which I did because I want to show that I am not forgetting you guys and the channel 😊!

[@evan.5967]

@@PhysicsMadeEasy Ohh it it because you were moving houses

[@PhysicsMadeEasy]

@@evan.5967 And country ! 😊

[@ButchNews]

In theory, one may measure the diameter size of an Electron. Axiom: things that are equal to the same thing are equal to each other. A mind experiment. One coulomb per sec is one Amp and we know how many Electrons are in a coulomb. So, with a super conductor cable, we measure one light second's worth of cable and allow only one electron at a time to pass... pretend it's in a vacuum if that idea is too ridiculous for you. So our conductor is a vacuum allowing one electron, at a time, to pass. We get our nano second clock out and open the gate for one second/one coulomb and divide one light second's worth of distance divided by one coulomb worth of Electrons and one has one's Electron diameter. It's a mind experiment, don't go ballistic on how impossible that is. A light second long line of paired electrons (so they won't repel each other). Count them... = one coulomb's worth. I love electrons, they are life. Everything we see, touch and smell or think is controlled by Electrons. In my private world they are shaped like an icosahedron and composed of 20 gamma particles. With enough energy and a really tough target, one may smash electrons into the Gamma particles. But what do I know?

[@PhysicsMadeEasy]

OK, let’s consider 1C of electrons. That is 1/1.6e-19 = 6.25e18 electrons. Now a tube of 1 light second. That is 3e8m. You claim that if you pass 1A in this tube, you would get 1 Coulomb held in the tube of that length, that is 6.25e18 electrons side by side. That gives you an average diameter for the electron = 4.8 e - 11m. The result is fun as it is about the radius of an hydrogen atom at ground state (which could be seen of the range of the electron cloud). The radius of an electron is known to be less than 10e-18m. Your reasoning appears to be based on electrons travelling at the speed of light… which they never do (electrons have mass.). But do continue playing with your mind like this!

[@ButchNews]

@@PhysicsMadeEasy Yup... it is an impossible reality experiment. I thought it would be neat to compare that size to other sizes suggested. In my universe reality, I go with the Plank constant as being the diameter. My theory of reality has an Electron being of shape of an Icosahedron... 20 Gamma particles. That allows the Electron to be smashed and the possible rubble can include a neutrino, two Xray particles or else a total of 20 Gamma particles. In my reality the Gamma particles are magnetic and as close to the Dark Matter we are seeking as we are likely to penetrate... using particle/motion physics. Relativity is all rather moot because the time factors are so fast they are living in a reality where a pico second is an hour. The neutrino is 10 Gamma particle and extremely unstable. The Xray particles are 5 Gamma particles and extremely unstable.

[@ButchNews]

What else... I see atoms as being constructed in a manner similar to Hoberman Spheres where the Electron is the all purpose ball joint with 10 possible poles.

[@ButchNews]

@@PhysicsMadeEasy I was thinking that, rather than the diameter of the electron, it has to spin one spin to complete a wave so, rather than the diameter. one would divide the distance by 6.25 x 10(18th) by the CIRCUMFERENCE of a circle, so the final answer will be divided by Pi (3.14159) so that would make the distance smaller. There is the issue that electrons don't really travel in straight lines but they would have no choice in a conductor one electron wide... also didn't allow for the skin effect. In any case, the field around the conductor would be a circle which would act as a magnetic shield of sorts. It would seem to indicate that one volt would give the required spin to do that or one second. I got onto that thought after Veritasium's silly idea that a metre gap between wires would allow for capacitance and his ridiculous answer for the time for the light second wire to conduct a current. I no longer trust anything he says.

[@ButchNews]

Here's a physics mind experiment I'm thinking of. Put a block of Plutonium into a gold Faraday cage, suspended in the center for best results. Now, on the outside of the gold Faraday cage attached thermal couples to turn the expected heat into electricity and, also, attach a conductor to the outside of the cage to capture the Beta particles hitting the gold... the high velocity electrons the Plutonium is releasing constantly. It is the electron supply which should have a different charge than the Earth so the other "wire" is a rod into the Earth, maybe needing a capacitor. Still thinking about it. With any luck at all, one would have a nuclear 1.5V cell with two outputs... beta absorbing and heat absorbing, one's home made nuclear reactor. Would it work? I don't know but I'm thinking about it.

[@PhysicsMadeEasy]

The idea is interesting, but you should dive a little deeper. First you should use a fuel that decays Beta,. Pu239 tends to decay alpha into U235. You should select the fuel considering the half life, so that you find a balance between the electrons produced and the heat they would provide. Too much and the gold would melt, too little not enough current. Also the KE of the electrons produced is huge (MeV range), while for photoelectricity, we are more in the 10eV ranges. Most of the energy would be heat, melting/vaporising your cage. Better transforming the heat into electricity instead of trying to collect electricity directly (and in that case, alpha decay is more effective, because alpha particles have a larger effective cross section). Even though, imagining you could generate low energy electrons: Then you should reconsider the receptor. Why a faraday cage? Some photoelectric material enclosing the fuel with the suited work function would be more effective. And behind the material, some water tubes to evacuate the extra heat. Search the internet, I am pretty sure, some have been thinking of some designs, maybe NASA (long time probes like voyager 1 and 2)

[@ButchNews]

@@PhysicsMadeEasyGuess I forgot about those pesky helium nuclea. Just thought that we must waste a lot of Beta radiation that could be turned into electrical force. There is a heat problem too but that is another normal source of taping radiation energy... small scale reactor, or something like that. My reasoning for the CAGE is that Electrons of same physical spin repel each other and they would be trapped inside the cage... gold is a conductor with tons of flirtatious electrons so it would be easy to tap the field on the outside of the cage directly or by induction with another gold plate (make the cage 1/2 of the capacitor... the more surface area the better for this... you can't get enough surface area. Where was I? Haven't thought enough about that one.

[@ButchNews]

I've been trying to think how I would word a video about my thought process of measuring electron size by an imaginary light second wire of LRLRLRLRLRLR electrons... put them in spin pairs Lspin/Rspin together as pairs in a one electron size to imagine the diameter of the electron my the Ohm's Law rule and our best measurements of a Coulomb. I gather it has been adjusted a couple of times in my lifetime... I'm 77. I just looked up the basic numbers yesterday but haven't done the division to see what it would give.

[@hakeemjinna935]

Great great

[@joe_ninety_one5076]

The error formula was misleading. The fractional error of a product is not the product of the two individual fractional errors, or it would be zero when one of the factors is known perfectly, as in this case. You have to take the square root of the sum of the squares of each individual fractional error. The result will be the same as that stated in the video. Because the fractional error in the frequency is zero, the fractional error in the speed is about the same as that of the wavelength. Great video on the physics side though, and I have just watched the one about light reflection which is a model of concise clarity.

[@PhysicsMadeEasy]

Hi Joe, You mean the equation on the bottom left of the board around 12 minutes 30, . The sign between the fractional errors of frequency and wavelength is a + (for addition...) :-) Thank you for your kind comments too

[@joe_ninety_one5076]

​@@PhysicsMadeEasy Oops! I blame my screen resolution, but I'm good at passing the buck. It is still incorrect, but in a different way that at least does give a sensible result when one of the fractional errors is zero. It is a trivial point, though, in a seriously good presentation.

[@Masoch1st]

Very cool man

[@mannmohan3009]

fsntabulous...

[@christopherus]

This measured the speed of light in cheese, not in vacuum.

[@PhysicsMadeEasy]

Good point I didn’t think about that, maybe I should use Emmental haha ( A cheese with holes). Actually, it would probably be a complex combination of both: Considering for example, that the standing wave formed is based on the boundary conditions of both the microwave oven and partially of the cheese, and considering the heat exchanges at the air /cheese and plate / cheese interfaces, the potential refraction / reflection at these interfaces etc… Also as you can imagine uncertainties on the measurement are quite high, in this video we just get an order of magnitude…