I highly respect you doing these experiments and reporting them. Keep up the good work.

I can't resist making a comment about your vacuum chamber. I always enjoy when it shows up in your videos, and it definitely was the tool that propelled your channel in the first years!

I know this will probably get lost in the comments but sometimes when I’m home alone I like to go out in my garden and cover myself with dirt and pretend I’m a carrot.

the spectrum looks like black body radiation, perhaps the infrared is turning into thermal phonons on the graphite surface

There is one thing I now know: I need a vacuum chamber.

When you said that you weren’t sure what was going on, and that’s why you’re posting a video to get our thoughts, I was thinking of posting “Black Body Radiator?” Turned out to be the case as you kept pushing to figure it out. I love your videos! Thanks for all the hard (but fun) work!

I really admire the fact that you left all the parts where you weren't sure about the explanation, even though at the end you could have just edited it all up with the results and upload a video where you "know everything" - this really shows your scientific spirit!!!

I always wondered why the laser card would get saturated (or I guess unsaturated).

I’m a scientist with a Master’s degree in organic chemistry. I find this guy much better than I could ever hope to be. Keep it up Action Lab.

Send this guy a new radiometer!

I feel like I would have bought a new radiometer and made sure it works just as good as the old one before I smashed the old one. Sometimes new things don't work as well as the old ones did!

I really love the way this one was presented. Felt like you discovered something then through experimentation, figured out what the cause was. Like watching science happen, rather than being told how science happens. Nice job :)

the part where the light was confirmed to be white by using the diffraction grating was kind of genius

The second you said you shouldn't be able to increase the the frequency I immediately thought how the hell does a green laser pointer work then! I'm so glad you answered that.

Hi Action Lab, Nice video and demonstration of that effect. I'm an engineer specialized into organic and bio chemistry and I know a lot about chemistry and science, but less about specific aspects of physics. I had an idea about your experiment but I had to first check onto wikipedia what they say about Black body and Stokes-Raman. I found that wikipedia under Black body states litteraly into the chapter "Near-black materials" that: "They also have application as solar energy collectors, and infrared thermal detectors. As a perfect emitter of radiation, a hot material with black body behavior would create an efficient infrared heater, particularly in space or in a vacuum where convective heating is unavailable." So this is precisely what you displayed :o) Your IR laser hits the target (black or white; with black being a better absorbant and less direct reflection emitter than white); because it is under vaccuum (partial or near total), it will limit convective heating (and/or cooling) by surrounding gas molecules; so the heating happens into the spot shined by the laser beam; then it increases with the time of exposure (observed by the glow seen into your video between 3:49 and 4:12; that passes from orange to yellow to bight yellow-white); the ray then heats up the coating (sometimes with smoke) and the metal underneath; the molecular agitation into the solids then dissipates it thermaly into the metal radialy and concentricaly to the beam spot; then only radiative emission of the black body can be observed (as if your spot was a white source of light (like the Sun, like old bulbs of carbon or tungsten (W) filament heated by their resistivity under the passage of current through it) and it display the all wavelenght (color) spectrum of those (of course the light re-emitted is < or equal to the light from your laser (otherwise you would have created more energy than furnished). So by activating the spot, the light takes some time to get ful emission intensity (ta); and conversely it should do the same, when the light is closed; the spot should glow darker by passing subsequently to lower wavelengts (yellow, orange, red, infrared (heat)) and this takes a little, but stil finite time (te). This in principle should be observable with a spectroscope with a dynamic of extinction caracterized by a more and more prononced red shift and IR (from blue to red - to the right); the enlighting fase would go counterwise of course with an increasing blue shift (from red to blue - to the left); lets say a "full color spectrum sunset". --------------------------------- Now regarding your cristal doubling frequence; it doesn't contradict the principle of emitted frequency is usually < or equal to incident frequency because two photons of IR produce (more or less - :o)) but one photon of green light is less photons. A bit what happens with a tide of water made of molecules with an average energy level; but when hitting a surface perpendicular to it; some droplets of it can go much higher than the tide height. Probably that in a near future some other cristals with such rare effects will be discovered or rendered public... (see for example below anti-Stokes shift). There are other cases where the frequency rule doesn't seems to hold: 1) When looking at Raman spectrum; it looks as if shining a laser frequency onto something makes 3 types of rays; a) direct reflection or scatering at the same wavelengt as initial b)Stokes shift (red shift) that kind of gives a finger print of the molecules (kind of fluorescence type) thus lower frequency is emitted than the incident excitation frequency. c)anti-Strokes shift (blue shift) that also provides info onto the enlighted molecules. As a matter of facts a) >>> b) >> c) (c is a very very rare event statistically) So "b" needs very strong filters to cut off "a" (and "c" will need even more efficient filters because its intensity is very low) Int(a) >>> Int(b) >> Int(c) Wikipedia states under Stockes shift: "Anti-Stokes shift If the emitted photon has more energy than the absorbed photon, the energy difference is called an anti-Stokes shift; this extra energy comes from dissipation of thermal phonons in a crystal lattice, cooling the crystal in the process. Yttrium oxysulfide doped with gadolinium oxysulfide is a common industrial anti-Stokes pigment, absorbing in the near-infrared and emitting in the visible region of the spectrum. Photon upconversion is another anti-Stokes process. 2) The famous effect of relative to each other speed of emitting source and observer; the Doppler effect... very observable with sound, but also with red or blue shifts of galaxies. So approching galaxies (source arrive towards observer) or if we come closer (observer approches source) (or if both reduce their distance towards each other) will produce a blue shift that may look like frequency is higher than it should if everything was still and not moving at all. Regards PHZ (PHILOU Zrealone from the Science Madness forum)

I still cannot classify the way you approach problems. But your intuition, curiosity and persistence yield a stream of continuing discoveries. I am glad you traced out the incandescence. Perhaps you did find a practical way to use long wavelength IR to make white light. As long as it is reproducible why quibble? "All I've got is this IR laser, but I need white light. Stick it in the vacuum focus it, and be sure to cool it so the lattice or plasmonic states do the right dance and sing the right frequencies." You helped me understand "high harmonic generation" and "frequency doubling" better. And I have never seen those "infrared to red dot laser paper"things before. Or the "glow in the dark, draw with a laser thing" before. I wish I had time to translate your videos into "What are reliable ways to model this, calculate what is happening, and apply it to broader classes of materials and to make new devices or predictive phenomena" web pages that anyone can use to explore what you found, and "make predictions and make new things to share with everyone in the world." If you get a chance, please look at 3 axis MEMS gravimeters that are able to track earth tides. They are sensitive enough to track the sun and moon vector tidal gravity in real time. All three axes almost exactly match the Newtonian vector tidal acceleration with only a linear regression for each axis. Maybe you could try to use an atomic force microscope to monitor tiny movements of masses, when you differentiate the position, it is velocity. Differentiate again and get acceleration. A "gravimeter" is simply an accelerometer sensitive enough to track the sun and moon. Arrays of cheap devices, around the world should be able eventually to monitor gravitationally hot spots inside the earth. Places with more than the usual share of local acceleration changes. Like earthquakes, surf waves, volcanic flows, ocean flows, atmospheric flows and turbulence. Richard Collins, The Internet Foundation

Hey Action Lab, thx for all the good content. Always curious many times surprising! Have a nice holiday and keep up the good work! You are an inspiration for many!

As an optician, it was incredible for me to see white light from an IR laser. Thank you so much for the explanation - this is a very interesting effect that can be used somewhere.

A) I will never, ever make fun of your vaccumm chamber, I want to make one, and if I had one and would put stuff in it daily. B) I truly respect your willingness to destroy a sentimental object in the name of science. C) I love how you find truly unique things that seems like they shouldn't exist and then explain in clear understandable language why they do exist, sometime really small little things that are a huge surprise and result in a deeper understanding of how the whole universe works

That's incredible. I've said it before, I love educational KZfaq but this channel more than any other makes me say "wait, what IS going on here?" Either phenomena I've never seen before, or explanations that blow me away. Great stuff!

Did you notice the small point of green light reflected by the radiometer glass @ 3:51? I would be curious to understand the mechanism of this phenomenon.

As an optics enthusiast, I feel amazed by this experiment. You rock! Thank you.

I love how you point out that these effects are so weird. That's precisely my reaction. It keeps me curious when I notice stuff like that.

Would love to see how much heat is left in the black part of the radiometer with an IR meter

I was thinking about anomalous luminescence but it turned out to be good ol' burning stuff to produce light.

How about using thermocamera to check the temperature of the spot illuminated with the IR laser?

That's amazing. I hope this video goes viral! Thank you for your work and content 👍✌️

Hello from the other side! You may have studied chemistry, but I see you as more of a physicist than I have seen in most of my peers in the past. Experimental physics is just wonderful! In order to be a good experimenter, experience is advantageous and creativity is indispensable for the implementation of the experiment because of...but it is much more important to "pick the right questions", or questions in general - to nature, technology , whatever - to be able to ask. In this video, this fact was highlighted so well! Just great, thank you. I hope you will be able to fill many inquisitive minds with ideas and insights in the future. LG from Vienna

Notice an excellent usage of the scientific method here! He kept doing different experiments and showed his discoveries as he went. While he didn't come to a conclusion, he tested several hypotheses.

i always wondered about different types of molecular crystalline structures, and how we artificially create some with specific arrangements? it's kinda like making graphene but with crystals in bigger chunks? i would love an entire episode on this and how it can be used to manipulate light wavelength and possibly discover new properties of quantum physics?? i was thinking it could be combined with light and heat energy to convert it with an artificial process of abiogenesis with controlled parameters! but i don't know what's possible and what not with current technologies and what we can find naturally on earth and in space? and possibly how to discover new arrangements, the theoretical part of vector physics. fascinating stuff!

Whoever makes fun of your vacuum chamber belongs in one. Just found your channel and I'm hooked. Thanks for your wisdom and humility

One of your most interesting videos IMO! Happy new year 💥

Nice video! I think supercontinuum generation would have been very unlikely. It is a process which requires the material to be mostly transparent at all wavelengths (both the input laser wavelength and at the generated wavelengths). Also, it requires an extremely high power ( ~ kW), usually obtained at the center of ultra-short and very focused laser pulses. This is because the type of light-matter interaction with the material that is involved (3rd order non-linearity) is extremely weak in most materials. Also, depending on the strentgh of this non-linearity, the optical pulses should travel in the material for a given length for the spuercontinuum process to be effective, for example few cm or meters in optical fibers, or few mm in photonic chips with more efficient materials. Though it was a nice idea and congrats for managing to rule it out experimentally !

Great video, you should mention that the number of visible photons coming out from the heating is less than the amount of photons going in from the infra-red source, and that that's how energy remains conserved.

So cool! Love seeing science-you know, that actual process of curiosity, discovery, testing, figuring stuff out. Love it!

That was one of the most simple but impressive phenomenum i had sen on your chanel! Thanks for the explantations

You should make a radiometer with Musou Black and White 2.0, or if you want to go further... perhaps Singularity on the black side and Spectralon on the white side.

Great demonstration. Les' Lab latest video literally shows how he made a "DIY Supercontinuum Laser! The Ultimate White Light Laser!" Neat timing for some neat systems. You can maybe give him some props and subscribers by referencing his video and maybe doing the same or even more homebrew?

A brilliant demonstration of science in action. I enjoyed that. Thank you for sharing.

I love this video. Having someone say I don't know, let's learn more is so rare. Showing us the reasoning and coming to a final conclusion through experiment was just amazing.

A lot of times, if you take the base off of those radiometers, they have a valve stem like an incandescent light bulb. I was hoping you would have done that to release the vacuum instead of cracking the whole thing. That way you could have used your vacuum chamber and revived it afterwards.

The sacrifices you make for science!

amazing work, you keep improving, your best work is yet to come.

This is really a nice video! I am a researcher in the field, I will try to comment in the simplest possible way. Generally speaking, it is possible to obtain supercontinuum generation even with continuous wave laser. One of the main source is a process called four wave mixing. Four wave mixing is a third-order non linear process. This means that you need really a lot of power and tight focusing to have it with a continuous source. Moreover there is a lot of power directly transferred to the material, so it is also easy to damage them. To avoid this, in our field we prefer femtosecond laser in order to effectively generate supercontinuum. Also the frequency doubling that you are showing for generating green light is a second order non-linear process. So it is much easier to handle it even with a laser pointer. Considering the low amount of power one can have with a diode laser, the easiest explanation that comes in my mind is that you are emitting a "black Body" radiation. In vacuum you expect to be much more efficient since there is no thermal contact with the environment, so the material can reach higher a temperature and emit in the visible spectrum.

I thought that it was probably better in a vacuum because the air was mainly conducting the heat away and also taking some of the heat away through convection.

The Action Lab will one day be the greatest villian this world has yet too see

This was such a cool video! *Totally worth the length. Loved every minute of it* 🙌🤩

Very interesting vid! Thank you Sir. And happy new year 🎈

Your videos are always interesting, many times I have expected you to hurt yourself, I am glad you have not and thankyou for your efforts.

Very interesting! I wonder, is it just because the vanes are black that it works well or is there a coating on the black side of the vanes that also interacts with the IR?

This is my favorite episode! Thank you SO much!

from the seemingly continuous spectrum i thought of a blackbody emission, glad to had it guessed right. what amazes me is how bright it gets, giving what it seems to be a

Just Imagine one Day he actually discovers something new by just making these science videos that would be crazy!

Wow, that was really interesting!

I love your experiments, they are so fascinating to watch and love when you use the vacuum chamber 🤍🤍🤍

I learned something very important today from you. This was an excellent presentation.

This man never fails to surprise

Next video you can show how you Fix it, and make more radiometers.

Supercontinuum in Multimode Fiber is Les' Lab latest and worth of watch. Great detail and amazing output!

Showcased some cool concepts, thanks for sharing.

If you spot it with a udible frequency pulsed laser you can hear the frequency too, photons and phonon will be produced by this carbon coated surface

I'm still left with the question how a low power laser can burn the radiometer.

you are so incredibly smart in the most non condescending way. its really great. thanks for all your vids!!

Wow! This is a pretty cool effect that I've never seen before, crazy what light can do! 👍👍👍👍

I enjoyed it.

You need to check the temperature of the Dot because the spectrum appears to be Black body. Your Laser is heating it up but Radiative cooling is extremely bad.

Super interesting video! Also, the vacuum chamber is a staple of your channel, I'm always happy to see it! ❤

That was interesting, thank you for sharing and your efforts❤

You don't seem to be careful with IR laser. They are extremely dangerous and can inflict serious damage to eyes by accidental reflection that you can not see (and so there is no protective reflex).

sorry but if it's a matter of incandescence how long can it last before the material carbonizes? You should have tried on the white side as well, what material are the black and white diamonds you used made of? maybe the glow is due to some component of the paint..i don't know why but i can't believe it's a glowing issue due to high temperature, please keep thinking about it and see if you find other possible reasons.

That was my initial guess, that it got really hot. At first i didn't know there was a vacuum inside that bulb. So i thought there was some super absorbent paint on those fins that would easily glow. But once you said there is a vacuum inside it i realized that it glowed white hot because it had no way to transfer the heat away from it. Air is pretty conductive for heat after all.

The reason it works in the vacuum is because of the barrier between. In this case the barrier is glass. Energy is going through the glass to turn the blade. The dot you see is the source wave crossing back on itself, or twisting (perspective). That results in reflected visible light as well as pull/thrust for the dark blade. The shape of the glass is important as well. When you used your chamber, the dot seems to reflect back from the barrier (chamber material) and not the blade itself. The bulb shape combined with the vacuum, converts the light to thrust and allows you to view the light on the next barrier (the dark side of the blade) from all angles as if that's exactly where you point it. But you are pointing it there. To me that ties into why time seems to stop around black holes. It's like the space between is the barrier, the distortion. From another viewpoint, that dot from the Infared laser (low pressure) is the eye of a reverse hurricane that draws in high pressure (and we see the point of the laser). The equal and opposite reaction is the spinning of the blade and reflected light. To me the basic function of reality, and a positive and negative charge with a gate between. The real control comes from the gates. Galaxies wouldn't look the way we view them without the gravity of a blackhole.

then try to put a sheet of paper in the vacuum and see if it turns bright with the IR laser......If find it really surprising given you wont feel the laser on your skin

So if you combine blue lasers you get ultraviolet that's so cool

yep, pretty interesting as usual... keep up the great work man!

This might have implications for increasing the efficiency of lasers used to produce a fusion reaction.

Thanks for the video. Your experiment with the radiometer can be very dangerous for you and also for imitators. It would be nice if you warned people not to duplicate any test without proper goggles. Why? Because without glasses, reaching up to a lightbulb causes reflections on the glass of the lightbulb, and those of an invisible laser. Depending on the laser, this can cause irreparable damage to the eye or even instant blindness in the worst case! I hope you wore safety goggles, which should go without saying when doing any laser experiments. That's why I ask you explicitly to warn against imitators.

That vacuum chamber is the real champion of this channel. 😹

This is a helpful video. Currently I am struggling converting a infrared laser to visible laser, your video provides me inspiration.

I think perhaps boltzmann curve shall suffice... vacuum means no convective/conductive light transfer, which means the dim laser is effectively able to impart more energy.

Really cool and interesting! Happy New Year to you and yours. 🎄🌟👍

Fascinating Video! Also there is another phenomenon to convert lower energy photons to higher energies called upconversion, it basically uses two atoms that get into a higher energy state and another atom which the energy of the two excited atoms gets transferred to which then emits lower wavelength light than what was used to irradiate the material.

Great demonstration of how knowledge and scientific process can lead to understanding of an unknown phenomenon.

This is the most interesting video that I’ve seen yet on this channel - and I’ve seen dozens and enjoyed almost all of them. And now I’m again missing my radiometer that I got at Disneyland more than four decades ago.

hello from spain, i'm amazed every time i watch one of your videos

You are such a nerd and I thank you for that. I find your explorations interesting and beneficial. ❤

I am always impressed by what can be accomplished by an educated and enthusiastic mind, and such simple tools.

This episode is one of your best ones. I like hoy you chase the answers

The lab that I work in uses those IR cards because we have a giant 100+ watt IR laser that we need to track across an optic table. It's probably one of the simplest "sciency" things we use in the lab but I never knew how it worked before, partially because I'm an undergrad and I don't know much, and partially because I had never thought to ask about something so seemingly mundane. That was a great explanation, thanks! Also, it makes a lot of sense that the laser seemed cold. Skin is terrible at absorbing infrared light so it probably just passed right through you. If you had used it on a black balloon I bet you could have popped it. Hope you are wearing appropriate goggles for this-as someone who works with high power lasers, I get paranoid about goggle safety and that laser seems pretty powerful despite its seemingly low image on the IR card. Be safe out there!

Awesome! Another episode of The Vacuum Lab!

Quick tip to break something like a lightbulb with minimum drama and extra damage to whatever might be inside: squeeze the bag with a vice or clamp which will not intrude into the bulb further once it shatters.

That is fascinating. As I commented below: radiative cooling is very efficient, actually. That explains why rescue blankets are so useful during mountaineering, etc. The human body loses about 50% of heat via radiation losses (at a miserable 37 °C) the rest via conduction & convection. Here the vacuum kills convection and conduction losses, so then radiation heat loss remains. Considering the colour temperature of the incandescence, it looks like it could be above 1600 °C, you can check using a camera to detect the colour temperature. Take a daylight balanced picture and use a black body colour chart. One burning Q remains: Why doesn't the radiometer vane melt? I was imagining it to be made from aluminium. Two actually: Does it work with C black powder in vacuum? Make your own using a sooting candle and a glass slide.

Nice one..& you could use the vacuum chamber as well..;) But can concept be used to warmup the oil in the new kinda solar energy generators which don't use traditional solar panels...!

I love this video...and all of your vids I've seen! Do you think you could make a super-efficient (and practical!) light bulb with this knowledge?

Nice video explanation😊👍👍

5:53 RIP Radiometer! A pure sacrifice for science!

love these science experiments

3:48 you can see a green speck there as well, this is really cool

That little "stirling generator" is gorgeous

This was great, thank you!