You know you have a powerful flash light when it needs a fan.

@VaginaLInspektA

3 жыл бұрын

No shit !

@JesusChrist-xc4yb

3 жыл бұрын

Laser cutters be like: *PS4 startup fan*

@theblukatlife

3 жыл бұрын

And only lasts 1 minute turned on at that power

@v1Broadcaster

3 жыл бұрын

not really, just means it's terrible inefficient and turns alot of energy into heat instead of light

@slickrick8279

3 жыл бұрын

What about those Water cooled LED's they are super effifient yet they need strong cooling

His neighbours are now believing that sun rises from West😂!

@zwz.zdenek

3 жыл бұрын

Actually half of his neighbors believe there are 2 suns rising East.

@Grze9898

3 жыл бұрын

Australians maybe?

@ImalentFlashlight

3 жыл бұрын

hahaha

@dogytwa7295

3 жыл бұрын

Bro I am Australian it obv rises from the west :/

@chillzwinter

3 жыл бұрын

It does in the opposite hemisphere.

I saw this thing 15 years ago in elememtary school for the first time and never understood how it works because noone else knew. Thank you for explainig it in the video. I always learn something on your channel.

@-danR

3 жыл бұрын

His diagram of the vanes didn't make any sense to me, so I'm still somewhat in the dark.

@MikkoRantalainen

3 жыл бұрын

@@-danR I agree that the diagram was not clear. I would explain it as follows (assuming I've understood this correctly): The higher the temperature, the more the molecules bounce around (the movement speed of the molecules is the same as temperature). Molecules move equally *often* when temperature is low, they just move at slower speed. When temperature on the one side of the vane is higher, the atoms hit the surface of that vane faster and transmit more energy towards the vane. The atoms on the colder side of the vane hit the surface with slower speed so they transmit less energy. The sum of these collisions is a non-zero vector causing the movement. When the surface of the bulb is made colder, the existing energy in the vanes (warmth) will radiate as infrared (this happens all the time but in case the bulb has equal temperature, it will emit similar amount of infrared back to vanes so net result is zero). As black surface radiates infrared energy faster than white (or mirror) surface, the black surface of the vane gets colder than the white surface and the rotation goes to another direction. In the end, I'm not sure if it would be incorrect to call this "pressure" because if you take a gas filled ball and you heat it (assume that the volume of the ball stays the same). Here the number of molecules inside the ball doesn't change, the volume of the ball doesn't change but still the pressure does increase. What is this pressure if not just the movement of the molecules hitting the surface of the ball? Is this really different from the collisions of the faster moving molecules hitting the surfaces of the vanes? However, if one thinks that the Crookes Radiometer spins because temperature difference "create wind", that's not true. Any wind would be about big groups of molecules moving in one direction but in this case, the molecules bounce around randomly and the speed of that movement causes the force to move the vanes.

@nathanegbert977

3 жыл бұрын

@@MikkoRantalainen I'm not satisfied with this theory. Say you were to increase the gas density in the bulb. While this would certainly increase drag, the ratio of faster to slower impacts on either side of a vane would remain constant. Thus the vanes would still spin, just slower. But that is not what we see. A radiometer does not function at all if there is too much or too little gas. When I shine a 2 watt UV laser into my radiometer, it spins so quickly that I worry it will fly apart. The beam is potent but it does not heat evenly. All of the surface of the vane remains at ambient except a thin stripe where it passes through the beam. Are we to believe this thin stripe is inducing enough kinetic energy into the gas to spin the vane into a blur? When I shine the beam at the white side of the vane, it does move at all. This is significant. The beam is certainly strong enough to heat the white side. Matter of fact, it would quickly heat both side as the heat conducts to the black side. When the beam is removed, you can confidently conclude both sides of the vane are equal high temperature, yet the vane still does not move. This challenges the theory that surface heat is powering the motion. So I don't know how radiometers work but if you are still reading, I'd be interested in your thoughts about a cold night last winter. My radiometer was outside the kitchen window (it's actually part of a windchime, so it's always outside the kitchen window). It was well after dark and it was spinning like crazy. No visible light other than moonlight. I'm at a complete loss to explain why it was spinning that night. I live in the country, no neighbors nearby. Cosmic radiation?

@MikkoRantalainen

3 жыл бұрын

@@nathanegbert977 When the radiometer is warmer than the environment, it will spin due temperature difference causing the radiometer to emit infrared. And this infrared light will be emitted faster from the dark surfaces. About the speed use can spin with a laser, try to stop shooting the light on the radiometer and count the amount of full rotations until it slows to halt. I would guess you'll find that the friction is very low - this is thanks to low friction in the axle and low drag thanks to low gas pressure. I would guess that if the pressure is too high (that is, close to normal air pressure) the relative difference on the both sides of the vane is too little. If static air pressure is 1N per 1 cm^2 and the temperature difference can create 0.01 N per 1 cm^2 you probably cannot have any movement. If static air pressure is low, you can get more relative pressure thanks to temperature difference because the same temperature will cause the same speed for each individual molecule even if there're less molecules in total. Of course, if you go full vacuum, there're no molecules to bounce around so radiometer cannot work.

@nathanegbert977

3 жыл бұрын

@@MikkoRantalainen It would be great if youtube would let me read more than one and a half sentences of your reply. Sigh. I'll check back later.

I'm going to buy that flashlight, shine it on a zebra and laugh at the tornado.

@scrambledmandible

3 жыл бұрын

This is the most beautiful comment I've read this past year

@rikospostmodernlife

3 жыл бұрын

Word salad

@icuabc1235

3 жыл бұрын

Word gravy

@garrettmandujano2996

3 жыл бұрын

Word bacon

@SimonStuff2000

3 жыл бұрын

Word flash light.

His neighbors: why tf is the sun out this late

@I_killed_that_beard_guy

Жыл бұрын

Sun is in the party

I was stuck with the second unsatisfying explanation, thanks for this video!

@dhanush5587

3 жыл бұрын

😂

@FIRE_STORMFOX-3692

3 жыл бұрын

Thanks *

@Chainsketch

3 жыл бұрын

Confusion

@humanbeing1429

3 жыл бұрын

I was stuck with no explanation at all because I'm seeing this for the first time. But now that I know what this is and understand how this works exactly, does it make us both equally favoured with information or does this make it unfair for you as this was introduced to you long before I even saw it? P.S. I'm not trying to be rude here but I've been wondering about such instances with information and knowledge through media in different parts of the world. What is this situation called and Is there a theory/study/ whatever it is called, on this subject? (Sorry for my broken English here. Any help will be so good and much appreciated. Much Love. A curious cat from India) Thanks.

@-danR

3 жыл бұрын

@@humanbeing1429 Sse of the word "unfair" here is confusing, as it pertains to issues of contest, competition, and the like. Even "disadvantaged" would be unsatisfactory. At best, you have been less "encumbered" by an erroneous explanation, having gotten the matter right, from the get-go. I don't think there would be a name or subdiscipline for that situation. For my part, I'm still a bit confused because I couldn't map the _shape_ of what he diagrammed to the geometry of the vanes, even in any abstract sense. All I got out of it for certain is that the classic version and the revised version were both wrong.

This channel is a gift that keeps on giving. Never a boring or uninteresting episode. I love it

Flashlight: *exists* Radiometer: WE HAV REAHCED MXAIMUN VLELOCIPY

@wowreacts9717

3 жыл бұрын

S P ED

@deckedoutpistol1821

3 жыл бұрын

BAN AN BA

@firefox5133

3 жыл бұрын

YE S BAN AN BA,. , GO FAST ER

The Action Lab : "OMG it's fast !" The Hacksmith : "OMG it's fa..." *breaks it*

@furioustester4056

3 жыл бұрын

Yeah lol

@Boredability

3 жыл бұрын

That is simply reality

@DHyre

2 жыл бұрын

For those who haven't seen the Hacksmith version: kzread.info/dash/bejne/Z5pqz6afk5jgl5c.html

I'd love to be a security guard and have that flashlight 😂🔦

@britishneko3906

3 жыл бұрын

and just blind intruders

@britishneko3906

3 жыл бұрын

@@darling_uwu and what is wrong with your name?

@citysaltlake

3 жыл бұрын

Yeah

@rooblixkewb7952

3 жыл бұрын

Just imagine trying to escape jail, and suddenly blinding white appears around you. What if there were 10 people shining this at the same time at you?

@britishneko3906

3 жыл бұрын

@@rooblixkewb7952 burns like a vampire in afrika

6:30 I was wearing headphones and started hearing music to my left. I thought someone is playing very loud music 🤦‍♂️😬

@sankalps17

3 жыл бұрын

Yes

@Bnslamb

3 жыл бұрын

I took my headphone off to be sure.

Awesome! Someone who goes the extra mile and states the REAL reasons. Thanks, Harlie

Whenever I wanna die, I realize that I'd miss out on The Action Lab's cool content which always brings me back to reality

@bigolventam6288

3 жыл бұрын

Thats awesome fam. Don't forget there are a lot of other really cool science things and content creators out there too in case he ever decides to stop making videos!

@69k_gold

3 жыл бұрын

@@bigolventam6288 I ain't gonna let him stop

@intimiderp7934

3 жыл бұрын

I don't know the likeliness of you accepting this message, but this is for the next time you're feeling overwhelmed in life perhaps. Jesus offers life in abundance, was struggling with depression for a long time, gave my life to the Lord and he brought me out of that pit of despair, ultimately the gospel message is that Christ died for the sin of the world, we are broken, this world is broken, we are self condemned beings, but Jesus defeated death by rising on the third day, He was prophesied to come from the beginning, if you repent (metanoia, meaning to have a change of mind) allowing yourself to admit that you need a savior, then trust in Him to save you and you will be saved. He freed me from so much, and He continues to sanctify, work in me, provide good works to walk in as well, He gives new life through His Holy Spirit we are born again, new creations. Anyways, God bless, hope that things pick up for you in life.

@StefanReich

3 жыл бұрын

@@intimiderp7934 Yes, God helps. Christianity not required (but possible)

@atriyakoller136

3 жыл бұрын

@@intimiderp7934 I wouldn't try to preach any sort of religion into someone who's in a vulnerable state, because they might accept it due to that and it's basically depriving them of freedom of choice of their own beliefs. But honestly, your message was actually among the ones that don't really force a religion, so it's not really bad.

This video deserves 7x as many views :( THIS WAS THE COOLEST THING EVER. You sir are gifted and talented. LOVE your videos so much.

First time I hear this explanation. And I really appreciate the proofs with the hot water and the ice cube. Excellent pedagogy. Hats off!

Sick!! Make more content like this It's so interesting, that my brain is spinning faster than a radiometer at 100,000 lumen

Too lazy to read a book, but can read 500 comments of people's arguing in comment section👍

@MikkoRantalainen

3 жыл бұрын

It just shows that you don't have interesting enough books. Obviously you're not avoiding the actual reading so it's not about lazyness.

@spencerlott1202

3 жыл бұрын

@Paranormal Stick i don’t think it worked :/

@TheBiscuitFactory

3 жыл бұрын

@Paranormal Stick am a vampire. Can confirm

@marcelenatoh4701

3 жыл бұрын

@@MikkoRantalainen haha

@xaven199

3 жыл бұрын

I’ll try... The Earth is flat, not a spinning ball !

Can we put it in sunlight and make energy?

@oakclass356

3 жыл бұрын

Energy cannot be created nor destroyed.

@harshil6043

3 жыл бұрын

@@oakclass356 he just wants to convert the light energy from sun to use it as electrical or mechanical energy what is wrong with you?

@danielclv97

3 жыл бұрын

Sure, it can be done, but will have a lot less efficiency then solar panels

@danielparker813

3 жыл бұрын

@@oakclass356 Come on now, you know what he meant. 🤨

@harshil6043

3 жыл бұрын

@@danielclv97 I do get your point and I certainly agree with it. Even the best Carnot engine wouldn't be able to harness most of the energy. But what the other guy said was totally absurd

I am deep in electromagnetism and did not know this. Thanks. I have this Crookes radiometer for around 35 years and I realized that the phenomenon cannot be due to momentum, for the reasons you explained. But I did not have a clue why it spins in this direction. It is the thermodynamics, really unexpected explanation. Thanks.

Excellent demo and explanation. I suspect the behavior with light was already well-known to most science geeks. But I'll bet most of us (myself included) didn't know about the behavior with hot water and ice. So thanks for adding something new.

Coolest thing in my life that happened today.

@MirageUchiha

3 жыл бұрын

It's actually one of the hottest things in my life today. Considering how hot it got with that Uber Flashlight shining so bright! 🔥 🌞 🔦

@guttireddysandhyarani362

3 жыл бұрын

Yep

@gamingwithdeku9992

3 жыл бұрын

@@MirageUchiha LMAOOOO agreed 😂😂😂😂😂

@neelamverma7852

3 жыл бұрын

Really?

@guttireddysandhyarani362

3 жыл бұрын

@@neelamverma7852 hi chotu

The BMW tailgating me with his high beams on would appreciate this flashlight

@L3THA1

3 жыл бұрын

Why are you watching while driving

@britishneko3906

3 жыл бұрын

@@L3THA1 stonks that's why

@oldschoolman1444

3 жыл бұрын

Know what the difference is between a porcupine and a bmw? BMW's have the pricks on the inside!

I love the deep dives and the explanations. I'm not all there yet with the edge of the fin actions, but I was one of those "The black side is heating and causing a push" guys. Thank you for the eye opening.

God bless you dude you come up with such creative ideas every time. It's very interesting to watch your videos and learn something new 😊

Super interesting! Never heard of Thermal Transpiration until now. I was expecting it to work like a solar sail.

@StephanBuchin

3 жыл бұрын

That's what I always thought but the ice cube test makes this explanation a clear winner.

Who loves "The Action Lab?"

@annamorales3681

3 жыл бұрын

Me

@koerga

3 жыл бұрын

Me

@shohjahonhamraqulov8439

3 жыл бұрын

Me too😀

@frankpalmer5085

3 жыл бұрын

Shouldn't the question be, who doesn't? One of my top 5 favorite channels.

@n0t_UN_Owen

3 жыл бұрын

Would you mind taking a ReCaptcha test?

Thank you for an excellent video. I stumbled upon your channel and have now subscribed to see more of your excellent explanation videos. Carry On Sir.

Great Job Sir....you have explained very clearly and concisely as what i feel as a Physics teacher

Realizing now that my uncle didn’t explain how his new toy worked accurately when I was about 8 years old. Dang. I’ve thought it was the photons being absorbed and reflected this whole time!

You can tell how bright the flashlight is by how the camera adjusts so that it looks like he turned off the lights in there. And then how 100 k Lumens overwhelm’s the camera’s ability to adjust and maxes out the sensor. Crazy stuff. That thing is like a weapon

Very clever trick with the ice cube in helping fully understand the way heat transfer in the air moves the vanes.

Never heard it explained like this. Excellent.

Radiometer, Hats off to people thinking, We can listen to *Radio* by Shining the light

@69k_gold

3 жыл бұрын

@dendo111 r/woooosh

@andricode

3 жыл бұрын

@@69k_gold Sadly, memes side of reddit makes you dumb, instead of "using reddit makes you intelligent"

@69k_gold

3 жыл бұрын

@@andricode Dude ik it's a joke now stfu I'm not stupid

@avaydon7679

3 жыл бұрын

Don't know who : This guy (with a name which we ain't get) is so funny. Me : Really Negga? Really?

@nyancat7486

3 жыл бұрын

@@69k_gold kzread.info/dash/bejne/noasrap8Z6TSeMY.html

The Action Lab: "It can't go any faster!" The Hacksmith: *Breaks device by shining flashlight on it*

@antoniomeraz520

3 жыл бұрын

Dude here we are talking real science no props

@Marhathor

3 жыл бұрын

He used a flashlight 14,14224x as powerful. The damn thing is taller than he is by a decent margin. Hacksmith Industries knows science, both real and fictional. Not sure what "props" you're on about.

@antoniomeraz520

3 жыл бұрын

@@Marhathor yeah sure dude

@Marhathor

3 жыл бұрын

Are you actually so completely braindead you can't find a video with millions of views when I tell you the channel and subject? Do I really have to hold your hand through the process of determining whether information online is credible or not? Stop being a clueless moron who seems to think The Action Lab is some kind of gift from God and that everything said on the channel has to be taken literally, exactly as it was said and is always 100% true. Watch this video before replying again, or don't reply at all. kzread.info/dash/bejne/Z5pqz6afk5jgl5c.html&ab_channel=HacksmithIndustries

@antoniomeraz520

3 жыл бұрын

@@Marhathor chill, am not riding that log of stuff

Thank you so much!!!! I learned something new! I always thought it was based on light not heat! So cool!

I've been trying to puzzle this out since I was a kid. I knew that all the wrong explanations that you gave we're in fact wrong. But, I never thought of that answer. Although this does count as research, I thank you so much for this video!

I think the Crookes Radiometer works more in infrared light than visible light so with a 10,000 lumen incandescent bulb it will probably spin the same.

@mikemills69

3 жыл бұрын

Like a megawatt infrared laser.

@MadScientist267

3 жыл бұрын

Long wave (far) infrared, eg heat, specifically. It doesn't really respond directly to higher frequency light per se, just the heat it generates, so yes a far infrared source (such as a red/orange hot element) will be more effective per unit of power input than near, visible, or UV for example.

@mikemills69

3 жыл бұрын

@@MadScientist267 such as...heat.

@proloycodes

3 жыл бұрын

@@MadScientist267 did you know that black absorbs all frequency of lights and emits them all as heat

@MadScientist267

3 жыл бұрын

An astute bunch on here I see... 🙄

The frame rate can't even match up the speed of spinning

Thanks. I've always wondered how this worked.

Wow. Superb explanation. This is one of the best scientific channels on yt. 💙💙💙💙

Make a lense adaptor to focus the light in like 1 square mm

Who else thought this was a light bulb at first?

@avaydon7679

3 жыл бұрын

Me

@TheCuCuTrain

3 жыл бұрын

Me

@Dudleymiddleton

3 жыл бұрын

Nobody I hope lol

@cleitonoliveira932

3 жыл бұрын

It is a light bulb, but with no light parts inside.

@ridhosamudro2199

3 жыл бұрын

@@cleitonoliveira932 so just bulb

wow now that is a bright light and very cool and loved the explanation

Fascinating! Thank you.

Someone loaned me one to play with and I was puzzled by it's operation... Your video has the best explanation, it was the demonstrations with warm water and the ice cube clinched it for me... I suppose you could use a thermal imaging camera to show that the vanes are getting hotter/colder, that would be a good follow on video and then in true "Action Lab" Style ( LOL 😁 ) put it in the vacuum chamber... will it still operate or... will it explode? And finally (if it didn't explode of course) you need to zap it with the world's strongest laser like you always do... will it operate or will the laser drill a hole through the vane? I hope not, I don't like seeing neat stuff like that being destroyed... but if you do it, you have a plan... so I know it was for a good cause: "science!"

@pecfree

3 жыл бұрын

You mean vein?

@raymitchell9736

3 жыл бұрын

@@pecfree No... "Vane" is the correct word: "Veins" are return path of blood to the heart, "Vanes" are fin like structures that spin on an axis like weather vanes (wind direction), and "Vain" is an attitude that is prideful or conceited... they sound the same, but spelled differently and have different meanings. They can be easily confused and English has more of these than you may realize... so I must check the dictionary to make sure I'm not making a Faux Pas... (and that's not even English) LOL 🤪

@pecfree

3 жыл бұрын

@@raymitchell9736 cool. Thanks

@jasmine2501

3 жыл бұрын

These are pretty cheap. A potentially destructive test would only risk 10 or 20 bucks. The one he's using in the video is a bit more, but you can get Chinesium ones for almost nothing.

@raymitchell9736

3 жыл бұрын

@@jasmine2501 Chinesium... I heard that one from AvE, I like his tool "reviews" and I like Big Clive where the el-cheapo PoundLand (it's like our dollar stores in the U.S.) product is in one piece only for the first 30 seconds of the video then it is dissected into a jillion bits 😁 So... I wonder what should Action Lab do? So far we have whitest and blackest paint in the world, most powerful flash light, burning lasers, and Vacuum Chamber of death... (I added that last bit) Did I leave anything out? What fate, I wonder, awaits the Crookes Radiometer? 😲

Can you try to make a big scale Radiometer. And connect it to a dynamo, to see if it can for example charge a phone.

@VoltisArt

3 жыл бұрын

Nor enough to even spin a dynamo to much effect at all. The blades are suspended from a glass cup on a needle point to get the least friction possible. The slightest bit of friction will overcome the air pressure differential. There is, however, the idea of a solar sail which could use radiation in space to drive a ship, but it might only work away from the nearest star. It would require a massive amount of lightweight film to be used for the sail, as radiation offers so little pressure relative to the weight of anything we'd want to transport.

@brokenwave6125

3 жыл бұрын

1. That wouldn't work. 2. Why? That's what solar panels are for...

Excellent. I really like this channel videos and this is the best!

Just chanced upon this and at last a better explanation of this radiometer - thermal transpiration is not easy to explain either!

8:14 that's not how you add vectors. The resulting force arrow should be tilted more to the right

@TechSupportDave

3 жыл бұрын

Yep. It's probably just a mistake but it is mildly infuriating that he somehow neglected the other vector and didn't add at all lol.

Shining 100,000 Lumen Flashlight on musou black

@thetwopointslow

3 жыл бұрын

Yes please

@skrigged9270

3 жыл бұрын

It will probably catch on fire

I enjoy the way you share your knowledge. Physics.

that was great. thank you!

@The Action Lab. You could have explained it in a much better. The real reason is the inelastic collusion of air molecules on surface. When a gas molecule/atom hits a surface it exchanges the thermal energy with surface based on the temperature difference between gas and surface. This is the working principle here. Upon irradation with light, the surface absorbs light and becomes hotter than air. The cold air molecules striking the hot surface absorbs the thermal energy (vibrational energy) of the surface atoms and reflects back at larger momentum than it's incident momentum. This difference in momentum is the additional kinetic energy gained by air molecules the same amount of momentum is gained by the surface in opposite direction. This creates a pushing force on the surface of the fin. The black surface absorbs more radiation energy is hotter than white surface hence receives more push than white side. This produce ned directional push from black to white which results in the rotation. Cooling the outer surface will cool the gas inside to lower temperature than that of the fins. The cool air again produces the push on the surface. But this time around the black surface is cooler than white surface as it radiates more blackbody radiation. This creates net push from white to black direction (opposite to previous case) and the fins rotates the other way round. One might argue that the exchange of thermal energy should reasult in eventually heating of air. While that is true the light feeds more and more thermal nergy into the fins which escapes through the gas to the glass walls and then finally to the surroundings. So, as long as the light is on, there is temperature gradient maintained and the fins keeps Rotatating.

@nathanegbert977

3 жыл бұрын

I'm not satisfied with this theory. Say you were to increase the gas density in the bulb. While this would certainly increase drag, the ratio of faster to slower impacts on either side of a vane would remain constant. Thus the vanes would still spin, just slower. But that is not what we see. A radiometer does not function at all if there is too much or too little gas. When I shine a 2 watt UV laser into my radiometer, it spins so quickly that I worry it will fly apart. The beam is potent but it does not heat evenly. All of the surface of the vane remains at ambient except a thin stripe where it passes through the beam. Are we to believe this thin stripe is inducing enough kinetic energy into the gas to spin the vane into a blur? When I shine the beam at the white side of the vane, it does move at all. This is significant. The beam is certainly strong enough to heat the white side. Matter of fact, it would quickly heat both side as heat conducts to the black side. When the beam is removed, you can confidently conclude both sides of the vane are equal high temperature, yet the vane still does not move. This challenges the theory that blackbody heat is powering the motion.

@milaanpatel4997

3 жыл бұрын

@@nathanegbert977 I will try explain your queries to the theory paragraph wise. First of all it is not moving due to blackbody radiation. It is moving due to temperarure gradiant between air and sides of the fin. Black body radiation is inderdirectly affecting the motion by maintaining this temperature gradient during cold(cooling the glass chamber) operation. Paragraph 1 query: The reason it is not spinning at higher density has nothing to do with drag(drag merly decides the speed). The thermal Conductivity of gas increases with pressure. At higher pressure, more gas particles interacts with surface and drains out the surface temperature more quickly. When this heat outflux from the surface approaches to the heat influx by the light source the temperature gradiant between gas and surface reduces. This reduces the momentum transfer and thus the unbalanced force. When the moment due to this force reduces to that of the static frictional resistance moment, it cant get enough push to start rotation. (You can validate it, by shining a brighter light at high pressure it should be able to rotate it as heat influx increases) . At very low pressure the conductivity of gas is very low hence the temperature gradient is very high. But here the number of gas particles itself are low to create sufficient force on the surface to make it spin. Paragraph 2 query: Your argument is still not clear to me. From what I understand you are trying to say that for a faster spinning radiometer, light will only see the edges of radiometer and they will not be enough to create the momentum. Well in this case the speed of light is way beyond the maximum rotational speed ever achieved by any machine. So no matter how fast it spins the light will still see the entire surface. The entire event duration of heating the surface is orders of maginutude less than that of the rotation period. Also the average thermal velocity of gas is around 460 m/s at room temperature, so a rotating fins would be way too slow to affect the gas particles collision on the surface. No matter how fast it spins, it is still slow to affect any of the physical phenomen that is causing it to spin. THE FORCE IS ALWAYS PRODUCED BY THE ENTIRE SURFACE NOT ONLY BY THE EDGE. Paragraph 3 query. Here is the thing. When you shine the bright light on the white surface. You say heat is transferred from white side to black side right? The fundamental law of thermodynamic says that the heat transfers only due to temperature gradient. So, in order for heat to transfer from white to black, white side should be unarguablely at higher temperature than black side. They cant be at same temperature unless you swith off the light source after which it won't spin obviously. Edit: while this are qualitative explanation. The actual operatioal conditions depends on lots of factors like, type of gas (mono atomic/diatomic), surface area, light Absorbance spectrum of fin materials, It's microscopic temperature, Surface roughness, pivot point friction, e.t.c so each radiometer meter should have different operational range of pressure, light intensity and wavelength and are difficult to quantify.

@nathanegbert977

3 жыл бұрын

@@milaanpatel4997 All that makes sense but I think you missed where I said I was using a 2 watt laser. A laser does not heat the entire surface. It only heats a line on the surface as the spinning vane passes through the beam. The vane only spins when the beam is on the black surface. When the beam is applied to the "white" side, the vane does not move. The vanes are made out of mineral mica, which is an effective insulator but the sheets are very thin and thus have low R-value which certainly renders the beam strong enough to heat the black side through the white side. If I understand you correctly, the temperature gradient of the vane is maintained by the color of the surfaces irrespective of which side of the vane receives the energy (such as when the device is in sunlight). If that is true, then it shouldn't matter where the heat is applied so long as a temperature gradient exists. So why doesn't the vane move when the laser is removed from the white side allowing the heat to conduct to the black side where it is radiated away at a higher rate than the white side? That laser beam is about 2,000 times the intensity of sunlight. It undoubtedly heats both sides of the vane several hundreds of degrees in a fraction of a second --certainly enough heat to produce a gradient. Something else to consider. Mica is mostly transparent to visible light. The "white" side of each vane isn't painted. It appears white because mica is shiny but it allows a portion of the light to contact the back side of the black paint. Food for thought. I don't know. Clearly I'm out of my pay grade here but it is a fun discussion. I'm gonna keep digging, maybe check the Wiki. Thank you Milaan for the detailed reply.

@milaanpatel4997

3 жыл бұрын

@@nathanegbert977 Thats a good point. I haven't used the laser on the surface. So, I can't tell the exact mechanics here. If you put the device in the sunlight there is always a black surface receiving the light at any point of the time. Here, you are shining 2 watt UV laser on white side of 1 fin, over the small area (assuming you are not using a beam expander) while the fin is stationary. The temperature gradient will exists from white to black while laser is on, and from black to white when its off, so theoretically it should create net force on that localised area, once laser is switched off. But from what I see, your laser spot size is very small, this results into localized heating to high temperature rather than heating of entire surface (as in case of sunlight). So even if the net force is produced, it is limitted to very small area of the fin which may not be sufficient to rotate the fin. Try increasing the spot size and repeat the experiment, I assume the fin would rotate as expected (if it doesn't results would be interesting). You may also try to measure the temperature distribution by thermal camera(with laser on and off) which would make thing more clear. Further, 2 watt is very high energy to be incident on the such a small area, this would result in other phenomenon of heat loss (majorily through Rayleigh scattering along with reflection). So that the surface itself would not be receiving the entire 2 watt. Only the light absorbed by the surface will result in heating. Hence, It is also important to know the absorbance spectrum of mica in UV region. This will give you estimate of how much light energy mica is absorbing corresponding to your laser wavelength. From what I know mica absorbs more light in visible/IR region (above 700nm wavelength) than in UV region. Which makes sense as radiometer are made to be used in sunlight. It is a good discussion. Challanging arguments enhances the knowledge. Knowledge is not decided by paygrade. There is always more to learn and discussion is an important part of it. I am always open to challanging discussion.

@nathanegbert977

3 жыл бұрын

@@milaanpatel4997 The laser does have an adjustable beam so the experiment is doable. And I do have an IR camera, but the glass is opaque to far infrared so it wouldn't be of much use. As an old rockhound, I may have a sample of mica in my box of goodies. It would be interesting to cleave a thin sheet and test transparency with the UV beam. I forget the wavelength of the diode. I built it back when handheld 2w lasers were unheard of. It's been a few years. 430nm? Anyhow, if the mica is transparent to the beam, then I agree. A wider beam on the white side of the fin should produce sufficient temperature gradient when the beam is removed. If not, then radiometers are powered by magic, which is what I've suspected all along. I will run the test this evening and let you know!

Hey man Ur great at science where did you learn all of this stuff

@ruchimaurya2425

3 жыл бұрын

And hey can u make your blackest black available on Amazon

@shargo498

3 жыл бұрын

On earth

@pravinjdev9529

3 жыл бұрын

For some, it comes intuitively..

@hyhh1246

3 жыл бұрын

On youtube

@nightRobinO_O

3 жыл бұрын

The Action Lec

This was really informative. A good topic for physics project 😉

Wow! I didn't know true explanation. Thanks!

Thanks sir from the deep of my heart 💛💛 You really made science interesting for me. There are dumb scientific KZreadrs In India playing with coca cola and mentos😂😂😂

Does this work on a massive scale...

@eylon1967

3 жыл бұрын

yeh like, we could build a giant one and make electricity with it standing in the sun

@AlphaOmega2

3 жыл бұрын

@@eylon1967 good idea.. I wonder if it's more efficient than solar panels

@cleitonoliveira932

3 жыл бұрын

Great, let's make a huge vacuum chamber with glass walls.

@Sandwich4321

3 жыл бұрын

@@AlphaOmega2 maybe but it doesn't seem like something that would make alot of power

@scacchomattho

3 жыл бұрын

It does. The wind works the same fashion

I would enjoy seeing you do a video on the 1940s amazing heat resistant material named “Starlite”. It was a scientific urban myth that was recently rediscovered. I’ve played with it and it is mind blowing. Love your work.

Excellent video. i had a radiometer as a boy and would watch it for hours. I went though packs of batteries. I was lead to believe your second explanation all these years was the correct answer. Thank you for the true explanation. I was not aware of the Ice trick. That Flashlight is insane.

So it's a tiny solar sail then? See if you can develop an automotive supercharger that operates on light. It's just crazy enough to work! Oh yeah, how much for the big light?

@h7opolo

3 жыл бұрын

when he said, "it's taking off", it sparked an idea for a solar-powered helicopter. 3:19

@MadScientist267

3 жыл бұрын

No. "Solar sail" is the original theory proposed by Crookes (but would be light bouncing off the white surfaces, spinning the other way). This works, but isn't what's responsible for the "reverse" rotation, as explained.

@michaellinner7772

3 жыл бұрын

@@MadScientist267 yes, yes I know. I wasn't writing a master's thesis. I was simply making a comparative analogous observation.

@-danR

3 жыл бұрын

@@michaellinner7772 Well, it wasn't an observation, comparative analogous or otherwise, it was a question; and the answer to the question is "no". How the Crookes radiometer works was explained in the video to _not_ work by radiation pressure, which _is_ the means by which a solar sail works.

That's the less efficient electric motor ever (-;

@justitroyal7032

3 жыл бұрын

No if we use sunlight

@tobiadedoyin811

3 жыл бұрын

*least;-;

@justitroyal7032

3 жыл бұрын

@@tobiadedoyin811 welcome auto correct

@justitroyal7032

3 жыл бұрын

@@tobiadedoyin811 are u a bot

@tobiadedoyin811

3 жыл бұрын

@@justitroyal7032 Nah. would a bot write yeh?...

Just watched a planerwalk vid where the guy claimed he was the only one on earth who understood how this works (also how light works)... Good to see someone making a video about it in the real spirit of science.

Great! I wasn't aware you could make it spin by heating of cooling it! I'll try it.

Who needs a lighthouse when you own such a thing…

"Due to this side being black side, it's going to be hotter than white side" *Hmmmm.....*

1:21 I got an advert for that Spoon app right as the screen transitioned to white. The flashlight was so bright, it changed the nature of reality. Wow.

I had a similar item whilst camping, itd sit ontop of the log fire made of metal and starting spinning nice warm air at us during the night.

Anyone here Well nope Oh hey Hi How are u Ohhhhh good OK bye see ya Well no one is there lol

@Murimansprophet

3 жыл бұрын

lol

I dont know why this was recommended to me but i def subscribed after! 😝

I think warm air ( being less dense) moves up leaving low pressure on black side and white side has high pressure so air pushes from white to black. When you used ice air near black was more hot than on white side so again by the same concept it moves in the opposite direction. In order to validate the statement one has to use another type of case instead of a bulb structure. I hope you do that experiment too 😊

I love this guy’s videos!!!

I taught will be a video like "knife at 1000° C vs chocolate" but the explanation is so, so great

Science was one of my favorite subjects growing up. I first saw one of these in like 1st grade and became obsessed with knowing how they worked. I got one for my birthday in 2nd grade and by third grade I posited the correct theory on how it worked. I really don't know how the other theories even took off the way they did.

Interesting. Got me thinking of what a marvellous set of radiometers could be set up to illustrate these effects quantitatively using the miniature electronic sensors now available tosay look at the tenperature gradient etc. Loads of experiments suggest themselves. Interesting though to think that it is really only a type of heat engine

I’ve used a same wattage UV flashlight and it spins the same speed as the same wattage regular spectrum led flashlight. I have not seen the ice cube idea yet. I need to think on that one. But this idea is not totally jiving with me yet. I like the idea Ken W. has, that is, it seems to be a static like capacitance charge/discharge force. The rarified atmosphere is for the conduction or conductive medium for the force to propagate. This static capacitance type idea makes more sense to me. But I am trying to be open minded about this presentation. Pretty cool stuff!

Love to see how this would work if the black sides were done in Vanta Black! If IR radiation works, can a TV remote control make it spin?

I had one of theses in the form of a Christmas ornament. The light bulb went into the ornament and the little fan spun. Nice to know how it works now.

In my youth I went about 5% of his effort! Really nice video.

I love your vids keep the work up I love science and this is really cool

So would it work better if the vanes were thicker, so there would be more surface acted on by the different air masses on the sides? Also, it should be noted that the wavelength is important also. A small ultraviolet light is more effective than a normal light.

8:19 You might add that the black side create also mention that the dense cold air always move where the air is hotter and less dense. So between the 2 panels, the cold air from the white side move to second black panel and create ai movement. While the panels are in rotation, the air between the 2 panels move at the same velocity but on the hedge panel you have a little vortex that create a drag. This drag also help to attract the air from the white other pannel to the nex black panel. And without this vortex you will have no motion at all in this experiment.

Nice explanation 👌👍

So, in essence, it's just a difference of pressure between the white and black side of each vane that's created by the thermal conductivity rate of each side of each one. It would seem as though a medium of some sort is a requirement within the bulb to operate. The basis of all motion appears to be continuous difference of pressure within some kind of medium.

Would it be possible to make one on a large scale for power production? Say have a section that is dark and a way to focus light by mirrors and lenses into the paddles of the radiometer?

Could this be used in a condenser to perpel the motor and the heat from the coil help keep the fan running

Fascinating! That explanation is weird, but interesting.

Just came across this video, even though it is 3 years old. The actual reason that a Crookes Radiometer moves is probably significantly more complex than the thermal transpiration or thermal creep theory. In an elegant series of experiments done by Jerry Liu at Stanford University using focused beams of light, he shows that this cannot explain the vane's movement in all scenarios. For example, a radiometer with HORIZONTAL vanes painted two-tone with one half white on BOTH upper and lower surfaces and the other half black on BOTH upper and lower surfaces (Hettner radiometer) will also rotate when exposed to light showing that thermal creep CANNOT possibly be the driving force. Not only that, it will rotate with the white half of the vane LEADING! Liu gives a much more compelling explanation using a phenomenon called transimpact. As the black surface of the vane absorbs photons, the atoms on the surface of the vane or in the air next to the vane absorb energy causing an electron to excite to a higher orbital (quantum jump). This causes the outer orbital shell to expand slightly producing an explosive-type interaction with adjacent molecules (air vs. vane) upsetting the balance of the Van der Waals forces and pushing them apart, thus imparting motion to the vane. Kind of like popcorn popping. In the case of the Hettner radiometer, this interaction occurs on the EDGE of the vane - rather than the surface - which is why it also moves with the white side (and edge) leading, albeit MUCH slower since the surface upon which this is occurring is much smaller than on the vertical vane, providing less force to overcome friction. Alas, the thermal transpiration explanation was attractive for a while, however it, like all of the previous theories, seems to actually be incorrect.

Thats a really well developed idea you have there. But, it seems you have completely discounted the possibility that its just magic? Lol. Good video. I really need one of those flashlights.

Can you please make a video explaining the resistance of rolling tire? And what make it stop

I love your videos keep making them

Could you use this as a perpetual power source? Use a large one to power a light that makes it spin, unused power stored elsewhere?

I learned something totally new. 👍🙏😎

If you increase the surface area, say put a bunch of folds on one side of the vane or other, what happens? Cools down faster/slower in relation to the other? Also, what is the best vane design for maximum force? Does treating the edges of the vanes increase force (F)?

Since heating and cooling of black side causes it to spin, is there any saturation temperature that it stops spinning so that from that point forth change in temperature causes it to change spin direction?

Very informative

MAGICIANS RED!! Joseph: Your stand is now a flash light?

If thermal transpiration is the main driving force on the vanes then could we expect porous vanes or vanes with a larger perimeter / surface area to produce greater forces and a faster spin vs the conventional square vanes?

And what shape would they need to be in to accelerate the spinning due to more edge length? Round? Beveled? Jagged? Great segment though! Thank you for putting that on I never really knew what the true story was!

You had me at "Shining 100,000 Lumen Flashlight at a Crook". That's actually what made me click. 😆