How could I not mention LIGO!

My brain during exam: *information cancelling device*

While making this video Action lab:everybody in the house stop breathing its making the light source vibrate

This is the same setup uses at LIGO that detected gravitational waves :)))

Hello Action Lab!! Whenever you post a new video, it will be around 10:00 PM in INDIA and after having dinner it gives a lot of satisfaction to watch your science experiments. Thanks a lot and LOVE FROM INDIA♥️♥️

Fabulous demo. Surprised you didn’t mention ligo after all that work.

There's a type of little kiosk in stores where if you stand in/under them virtually all exterior sound vanishes. Also, sound from speakers in the kiosk did not travel outside of it.

Could make one hell of a security system with how sensitive that setup is.

A flashlight that instead of lighting makes it dark ... Sooo it should be called unflashlight??? Or flashdark ... ??

Today's fact: Baked beans are actually not baked, but stewed.

Any odd multiple of half wavelength actually.. Since moving by an even multiple will lead to constructive interference..

Disappointed. Still waiting for the flash-shadow like on the thumbnail. 😂

Really cool aspect to this experiment; you talked about how doing something as simple as walking on the floor can change the phase between two light sources but temperature differences actually do the same thing so if you breathed over one light source you could actually see a phase difference.

What I have learned: my brain don't want to.

Which would absorb more heat when left in the sun: a computer screen displaying black or a computer screen displaying white? Also, do different colors display at different temperatures on computers? (Not left in the sun, but just on its own indoors.) Does blue display any warmer than red for example?

3 words for you. YOU ARE AWESOME. Thanks for giving us all of this stuff!

"Everybody please don't take a shit now it disturbs my not-light."

This video is exactly the reason why i got to know your channel. I had this doubt for a long time and when i searched it in youtube, i got your other videos on additive mixing, subtractive mixing and those on 'if black and white are colours'. Now my doubt is finally cleared. But i can't stop following your channel as your experiments are on the next level. Thanks a lot. It is actually surprising to know that you came to this height from crushing a golf ball on hydraulic press.

Love these experiments. I love learning new things that this guy teaches on science. I love that he makes it fun as well as educational.

I knew about how noise cancelation works with offsetting sound waves by 180 degrees. But I wondered if light cancelation was possible. Whe I thought about it I realized how hard it would be but am very happy now to see it explained in a video. Thank you!

_Those markers screech through my heart every time..._

We don't need a flash-dark in 2021, please continue your work, we don't need it, but we want it

Wow. This channel has put science into so many of my twin brother and my comic characters that we make. There’s a creature that has light cancelling eyes. Looks like it’s eye structure will have to be completely different than what I originally wanted it to look. One on the front which emits a light cancelling glow, 2 on the sides and on on the back of the head to receive light. Which goes into a bioliogical beam splitter type organ.

Love from INDIA The Action Lab!!! ❤️❤️❤️

this is basically a mini version of LIGO, they use the same mechanic to measure the tiny mirror movements to detect the gravitational waves

You are an amazing teacher. Keep up the great work. Thank you 🙏.

The coolest thing about this was how sensitive it was. That was crazy! :)

Wouldn’t be a flashlight then now would it, it would be a flashdark. 🤣😂😂

Hi action lab! Could you please make more videos on quantum mechanics stuffs...like entangled photons,eraser experiment etc !! Btw great video as always

Pretty cool experiment. I wonder what would happen to some of the wave patterns if you tried using a polarizing filter.

This channel doesn't disappoint, I was hoping to see a total cancellation here of the light. What if you did this in a anti-vibration & sound dampening room? an maybe throw in the vanta black as necessary for light control.

I think the vibration sensitivity shows a good demonstration of how high power telescopes need to be vibration isolated. People who have never used a telescope wouldn’t understand that. This device shows a good representation of that. The difference though is that a telescope usually takes longer to settle out after the vibration starts.

Blowing my mind again!

Really cool! Intresting that you can make a device that sensitive to vibrations, but yet so simple.

8:30 honestly that was the most intresting and cool part. id love a whole vid on just that alone

You are really funny in a geeky kind of way. I love it when you try doing things that you know won't work for us. Not talking about this video specifically.

Man, you're reading my thoughts!😂 I was thinking of the exact same thing some months ago! Thank you for existing! :)

People on the street: "hey where are my sunglasses?" Me:

Please try the "Delayed Choice Quantum Eraser" experiment - it would be so cool because it is a kind of time travel device (for subatomic particles at least)! @The Action Lab

Thank you soooo much. This is a wonderful visualization of concepts that come up so frequently in science and science explanation. Truly a service to education.

Love the idea of this! These are the experiments I watch this channel for. We do need to get you a nice, large white board though...

ohh! now i understand that's the setup they used for gravitational wave detector ! that much of accuracy is awesome !!!

Oh my god! That's my idea and I have been trying to make it possible. But it looks like it is impossible unless you put a black hole inside it because black hole can suck light. I am so glad you did this video

So well explained! one of your best videos! I think I know how gravity waves were measured now :D

Minor correction: "Any multiple of a WHOLE wavelength PLUS OR MINUS half a wavelength" will cancel out some of the light. Any even whole number multiple of half a wavelength will produce constructive interference (contributing to the light level) rather than destructive interference (canceling out the light level). A simpler way to phrase the correction is that any ODD NUMBER multiple of half a wavelength will cancel out the wave.

Me: just how sensitive are you? Soft boy: have you ever heard of a Michelson interferometer

I love your channel and you just seem like a genuinely cool dude! Much love and support man!

*Me in the lab doing this experiment* My friend: *lives* The lights: 🤯 Me: who allowed you to breathe

“Hey guys, today we’re going to be...” Every time

you also build an motion detector with this experiments... or an vibration, quite cool!

Hi Action Lab... I wonder if there is any beam splitter " equivalent " for heat waves ? - to cancel out waves from two heat sources. Your thoughts on this?

I will tell my science teacher this to escape not doing homework

This video is more useful than school

Wow, this could be a great movement sensor.

We lost a legend “grant Thompson” in these past few days,we are really sad about it so we don’t want to lose you, please be careful with your experiments!

Excellent explanation..... so in theory can we make a NAND gate or a Boolean function from this phenomenon?

Now I know where Vsauce got that thumbnail for his, 'What is the speed of dark?' video!

Great video, but there is one point that needs to be clarified: it is not enough that the light comes from the same location, to get interference patterns. The light beams must have constant phase difference. So, it is impossible to have the same results using an ordinary flash light, not only because is not monochromatic, but mainly because, like most light sources, including LEDs, emits photons in random phases. As far as I know, only laser light can do the work. Further more, even with lasers, it is extremely difficult to keep the phase difference constant between do different laser devices. So, in order to get the right result, you have to split a light beam coming from the same source, and this source must be a laser.

Another great video! Years ago I saw a picture in an encyclopedia of search lights arranged in a large circle. They were aimed at one point in the sky overhead. The beams were bright until they met at the focal point and beyond that they were not nearly as bright. The explanation was that the light beams interfered with each other. I’ve tried to duplicate that with flashlights and lasers in my house with no success. Have you seen anything like that picture in the encyclopedia?

This seems sorta similar to the polarized sunglasses trick.

By the way, if you record amount of oscillation of the interference pattern, would it produce sound? Might it be the way to make supersensitive microphone?

Hey this is a great video! Better than usual! You're a lot smarter than you sound! 😁😁😁😂❤️ J/k

One of the best things i have seen on KZfaq . Keep up this good work man, congratulations.

It always a gr8 experience on getting that free knowledge from you sir thanks for all the effort

@ The Action Lab Hey man, nice video again! Just want to correct two things. At 1:35, the trough of the wave doesn't represent low electric field, it represents electric field in the opposite direction to the peak. The peak is upward electric field, and the trough is downward electric field vector. Second is at 7:39. It isn't true that there would be no interference pattern if the mirrors were exactly the same distance from each other. There would still be an interference pattern, but the fringes shift whenever a mirror is moved. The reason is that the laser is not just a single ray of light. The laser light always comes out at slightly different angles, and hence should reflect off slightly different points on the mirror. The entire path of different portions of the light is different, and that's why some places interfere constructively, and other places destructively. So regardless of the mirror distances, there will be an interference pattern. Anyway, great and interesting video! I remember when I took physics III in college, we did the Michelson interferometer, and I took one of the tuning forks in the room and struck it. The When I brought the ringing tuning fork near the interferometer, it actually blurred out the interference pattern. My physics professor and I had two completely different explanations for this. I thought it was because the pressure waves from the sound were moving the mirrors back and forth 440 times per second (I think that was the frequency), and that's why the pattern blurred. He thought the pressure waves were changing the index of refraction in the air to make the light travel at different speeds through the air, thus making it go in slightly different directions.

His experiments : Light Cancelation My Experiments: Ho much lego could I put up without making it fall?

2 points to be noted to see interference: 1. The 2 sources should be coherent. 2. Interference doesn't always show. The distance between 2 mirrors from beam splitter should be multiple of ½ of wavelength + it should not be > coherence length. The wave train should interference with itself and not other wave train to see interference pattern.

It is thanks to this channel that I passed my 12th grade physics class

Just one correction. The dots on top of LEDs are primary lenses that are use to narrow the light beam not to open it. All the rest it’s amazing... 👏👏

Mr.Action lab,Please do a video on canceling magnetism.North,south and or both.Thank You.

LIGO which is used to detect gravitational waves uses this principle only.

YES!!! another ActionLab video!! I love it! 😊

Where did you get that light table Michelson Interferometer? I'm working on making a light table from a long coffee table. That would work really well as an insert component.

I love your channel a lot!! I am liking all the videos. 😋🙂 you’re awesome 😎 please make a video on how to see photons in light. Or atoms of anything .

So awesome. You think of some fascinating stuff to experiment with!

Actually even if the mirrors are equidistant from the splitter, there will be an interference pattern. The reason lies on the fact that the image projected are made of multiple "rays" and every ray travels a slightly different amount of distance (called the optical path) and arrive at the screen with different phases anyways. If your projected image is an infinitesimal dot, then there will not be any interfere.

I never understood how to cancel light but you gave me an important information i was thinking about an extremely sensitive ground vibration sensor for my snake robot and your laser fringe vibration gave an idea to make one

Very amazing,ilove what you were doing i learned something new bout this video Keep it up bru....👍👍👍👍👍👍👍👍👍👍👍

The difficulty in generating this with light and sound is the source of the two sounds originate from two different places. With different wavelengths for anything but monochrome light or a single audio pitch, the location of the cancellation is in different places for different frequencies. A polarizing filter with a 1/4 wave plate makes a unique optical filter. It is not a linear polarizing filter. The combination is often called a circular polarizing filter as it takes the delay of the E field in relation to the H field and this creates the wave that rotates while traveling. So far, so good with the physics lesson. How does it work to make dark? Obtain 1 circular polarizing filter and look through it. You can see through it but it darkens somewhat due to the removal of a polarization. Now the dark.. Look at your self looking through the polarizing filter by looking at yourself in a mirror. Turn the filter over and repeat. Notice anything completely black? The linear polarizer keeps the light in one polarization and he phase plate changes linearly polarized light to circular polarized. If you pass linearly polarized light thru (1) first, either all of the light will be absorbed or transmitted, depending on the rotation. This works as when an electromagnetic wave strikes a reflective surface, the E field is flipped, but not the H field, which reverses (reflects) the wave, but what was a Right Hand twist, is no a Left Hand twist, or visa versa. Now the reflected wave is the wrong polarization to be transmitted. With the filter flipped, the linear polarized light always reflects in the same orientation and always passes with little loss. ( a 180 flip of horizontal is still horizontal ) kzfaq.info/get/bejne/bNKGfNJqqJaydHU.html

As always the explanation was super clear! Thanks a lot :)

Hey, I'm working with a laser interferometer here!

Thanks to give some ideas bcoz long time I working on this thing... Could you try with actual flash light which have white beam... So actually i need to know....

09:12 TheActionLab: this is me, making baby TheActionLab #5 (I am not sponsored by Chanel perfume #5)

Just watched this a second time ... the action lab is awesome. Thanks for helping me and my kid learn.

Does this have something to do with the Michaelson-Morley experiment?

There was another interference pattern at the laser. The light was conserved with this second pattern. Its pattern is always opposite of the “screen” pattern.

If hypothetically you could completely cancel out the two light/photons, wouldn't energy conservation be violated? You generated two photons, but after interfering there are.. none?

3/4 of this video I didn’t know what he was saying

thanks god it's impossible to turn off every light, the government would impose taxes to the sun

I really enjoyed this video. Thank you!

a cool fact is that michelson interferometers were used to prove that light does not require a medium (called "ether" when postulated) like most other waves. michelson and morley hypothesized that for an ether to exist, light must go at different speeds in different directions, because the earth would be moving through this ether with a speed. they conducted a series of experiments at different locations around the world where they used a michelson interferometer to detect differences in the speed of light in different directions. a difference in speed would mean that the two beams would be out of phase when recombining, so for an ether to exist, there must be an interference pattern. however no interference pattern was observed throughout any of the experiments and now we know that the ether does not exist

I don't suppose it'd be possible to have a material that reduces in albedo when it's excited by some light source? My other guess was some polarized light and filter shenanigans, though I can't figure out how that could work.

My whole life, I thought that the Michelson Interferometer Experiment was actually the Michelson “Interferometer Experiment” and now I have learned that it was actually the “Michelson Interferometer” Experiment. Must have been the way my physics teacher accentuated Michelson. Well, you live and learn. By the way: The demonstration here is less than impressive.

I met James today at lagoon, big surprise :D

I'm going to invite some friends over for the action lab drinking game....we take shots every time we hear the word "basically"....and we learn stuff!

If it's so sensitive to pick up the tiniest vibration, why i can't see the pattern moves violently when you are talking?

Can you make a video demonstrating the sound cancellation idea?

Can you use multiple different blackout source sametime same place?

What will blow your mind... Use 3 polarization light filtering sunglass lenses. put 2 up, and rotate one. you'll see it get darker as they approach 90degrees offset, as light is blocked. Now add a third when light is blocked by 2 at 90 degress. Rotate the third one. MORE LIGHT will come through. You can filter out light, but then.... somehow it comers back after being blocked.

How about if you used a filter instead of the mirrors? I'm thinking of something like lenticular plastic or an opaque diffuser. What I think you're wanting to do is to homogenise the wavelengths of the light sources. Lenticular plastic will diffuse the light along the bars, but an opaque diffuser would cause the light to act more erratically.