If the thermal creep explanation were correct, then the spinning would eventually stop, when the heat exchange from the radiating surface and the source of light on the light Mill reached equilibrium. This is not what we observe.
The explanation is wrong. Tesla's ideas on radiant energy and his magnifying transformer were based off what is happening in the crookes radiometer. It rarified air in the glass. Very low oxygen (aether). Just like the upper atmosphere. A pure vacuum makes the veins not spin. Shine a laser on the black vein you get no movement. Pour hot water on the glass and it spins. Tesla said he developed a motor thousands of times more powerful than the Crookes radiometer.
Catastrophic error in explanation. If he'd stopped the rotation halfway and then reversed it, it would have been more correct, but it would be hard to tell with a side vide like that. Or he could have just had a video of one rotating on that green screen behind him.
This explanation isn't entirely accurate. The "thermal creep" is a _symptom_ of the fact that the veins are moving; it is not the _cause_ of the movement of the veins. It actually works like this: *(1)* More EM radiation (in the light spectrum and short-wave infra red) is absorbed by the black side of the veins. *(2)* The black side of the vein re-emits longer wavelengths of infra red which are absorbed by air molecules near the surface of the vein, causing thermal expansion. *(3)* The pressure differential causes the veins to be "pushed" with the black face trailing, since this is the side with slightly higher air pressure. *(4)* The air from the white side will obviously be seen creeping to the black side, since this is what happens when you move ANYTHING through air. _Also, the air pressure needs to be low enough such that the veins can move freely without much resistance, but not so low that there isn't enough air to be heated by the longer wavelengths of infra red being emitted by the black surfaces._
+Jim Griffiths You are wrong. Maxwell discovered that the warmer gas would simply expand in such a way that there would be no net force from this effect, just a steady flow of heat across the vanes. You must focus attention not on the faces of the vanes, but on their edges. The faster molecules from the warmer side strike the edges obliquely and impart a higher force than the colder molecules.
@Electrical equipment TAO these things and speed of vanes and pressure differential temperature these are all the function of frequency of electromagnetic waves
It's all about Bernoulli effect, the dark side getting heat faster so the air near this side is hot and it expand means more pressure and it push it, and if we put it in cold refregirator let's say, the dark also getting more cold and there will be less pressure so it will be sucked and rotate the otherway around..
I would like to add a hypothesis. If the black side absorbs light it gets warmer. That means the molecules making up the black surface vibrate faster. Now when a gas molecule randomly touches the black surface, some of the kinetic energy of the surface is given off to the air molecule (bouncing it off, speeding it up, raising it's temperature). So it pushes the air molecule away, and the equal and opposite reaction is that the air molecule pushes just as hard on the black surface. It is like if you push someone away from you, it causes you to also move away from them.
Just got one. This thing spins really, really fast in direct sunlight. Also tried my NiteRider 700 lumen bicycle light on it. Makes it spin like mad. The strobe mode makes it spin and look oh so cool.
If Crooke had the means of creating a full vacuum, he would have figured that out. But its worth noting that his theory about "light pressure" wasn't completely incorrect. Although photons have no mass, they do have momentum. But harnessing that kinetic energy would require an enormous and highly reflective surface area. It wouldn't be very practical for terrestrial applications. It's more useful to absorb the photons with solar panels and harness their energy that way.
Physicists are obviously charlatans. If momentum is defined as mass x velocity, and a photon's mass is zero, then for its momentum to be non-zero would require infinite velocity. Hoist them all! Host them all by their own petards!
BrightBlueJim Good point! Just keep in mind that the laws of physics that govern massless particles (and light speeds) are very different from those that govern massive particles. Newtonian equations like E=1/2mv^2 and P=mv fail to paint the whole picture since they fall apart when m=0. Einstein discovered an equation that paints a much bigger picture: E^2 = P^2 c^2 + m^2 c^4 With this we can see that a particle with no mass (m=0) will still have both energy and momentum: E=Pc Matter that is stationary and lacks momentum (P=0) will of course still have energy as well: E=mc^2 Notice that no particle can ever have both 0 mass and 0 momentum. If both m=0 and P=0, then E=0. This only describes nothingness. Interestingly enough, this is why photons are forced to remain in motion. Since they already have 0 mass, they are never allowed to have 0 momentum.
You have part1 of thermal creep backwards. Hot goes to cold, 2nd law of thermo. The energy is radiated from the black side to the molecules causing them to heat up and become excited. These molecules bounce around more frequently on the dark side than on the light side. This is typically referred to as pressure. Because they are bouncing more often, they are striking the surface of the fan more on the dark side than the light. It's this difference in pressure that cause the fan to spin.
That's the direction of conduction, however, we're dealing with fluid density and cold fluid is denser than warm. The colder gas (fluid) will rush to fill voids caused by warmer, low density gas.
I've inherited one from my Dad he had for MANY years. It is a beautiful one but I never knew what made it work other than the sunlight. Wonders of the internet search! Thanks for en"light"ening me!
I thought for quite some time that it was the mass of photons striking the dark side, propelling it, like a solar sail but it also left me wondering. Your explanation fills in the gaps. Thank you.
How can air particles be pushing the vanes? The inside of the bulb is at a near vacuum -- actually 7 torr (0.135357 psi). That means the air is spaced out with ~1 cm of separation between them inside the bulb. Hardly enough air to do much at all... if you could see the molecules you could count them! . Still seems to me that black side of the vane is pushed by light pressure (photons transferring kinetic energy to the dark side of the vane) to the tune of about 17 micrograms per 50watts of light energy. That is a small push but the kinetic energy builds until the vane begins to move and then it builds momentum. The reflective side of the of the vane reflects the light photons and kinetic energy is not transferred to that side. I think the inventor was correct.
the pressure hitting the white surface is split, half remains inertial and half is reflected, imparting less momentum than all of it being kinetic on the black face which doesn't reflect. And basic physics says it will spin in the direction the most pressure is exerted with the least pressure directivity providing resistance. Let's not forget the basics here. Just because white reflects doesn't mean it is absorbing more kinetic energy, it actually doing the opposite and absorbing less because half of it is reflected. And the very same amount is hitting the black surface as well, of which none is being reflected.. This is represented as 0.5p+-0.5p for the white surface, half the pressure absorbed and half of it reflected, canceling each other out essentially, but is mathematically represented as the half pressure being reflected by 1p over 2, or 1p/2, as half the pressure is absorbed and half is reflected. And on the black surface it's 1p/1, because the pressure is only going one way. So, the determining factor of spin direction is calculated as white face pressure minus black face pressure (or vice versa) as (1p/2)-1p=.5p-1p=-0.5p on what face spins bias. But let's ignore the most basic laws of physics that nothing can violate because it doesn't suit the theory and call it science when science is actually proving or disproving theories based on the principles of facts rather than belief or bias. If you are ignoring factors that don't suit your hypothesis, that is belief science, aka broscience, and not actual science at all. And ignoring the most basic laws and formulae of physics because they don't suit a theory is belief science, broscience, because you ignore basics that don't suit your theory and have thus traveled outside the realm of science and into the territory of religion. A theory is a guess, not a belief. And approaching science with belief is not science. Science is the process of proving one's guess either right or wrong, not proving it right because you believe in it which means it can't possibly be wrong because that would mean you were wrong. Science is taking it with a grain of salt and forming a new theory when one is proven wrong. Broscience is overlooking what contradicts your belief because you are so determined to prove it right because of your belief. Belief and science don't mix, approaching science on a belief never proves a thing because you refuse to accept the facts. Knowing is acceptance based on fact, and science is about knowing. Belief is about taking things based on faith or lack of proof, and lack proof is proof on nothing, as well as belief being the territory of religion and far from science. Ignoring the facts because you chose blind faith in your theory is not going to change the facts. Just because you can't eat an elephant in one big complicated bite doesn't mean you can't eat in a simple bite at a time. You can't skip steps or overlook facts, and you have at least three proofs of your own misunderstanding of why it isn't heat in this video by the way.
Good explanation! I just obtained my first Crooke’s Radiometer and was attempting to learn exactly how it works, and doesn’t work (an interesting story in and of itself). After reading several different explanations - including, surprisingly, some erroneous ones - I understood the mechanism best after seeing this video.
Except it's not. Basic Physics says half the photon pressure on the white face is reflected while all of the pressure on the black is absorbed, meaning the black face get's twice the pressure of the white face. It really is Photon Pressure. And removing the glass lens around it proves it, because if the heat source in the vacuum chamber at the same pressure with the vane, heat has no effect on it until it starts escaping through the tank, and then it spins backwards as photon pressure is released by the excitement of photons as heat passes through the glass in the opposite way, pulling photons out and exerting the opposite photon pressure on the veins, the white giving off more than the black thus leading the opposite way. And that is because without a lens between the heat source and the vane there is nothing to cause the heat to agitate photons into moving light. Never skip the basics, even the most basic taken for granted basic, and never take the basics for granted, because without the basic concepts, the complex ones fall to pieces, because complexity is essentially a stacking of basics. In fact the term critical thinking applies to the application of Occam's Razor. The simplest, or most basic, of solutions is often the best. And even the most complex puzzles have the simplest solutions. It's not about heat, but rather it really is about the photon pressure, or light pressure, an equal and opposite reaction on both surfaces. Equal pressure applied, unequal reaction to it. And let's not forget painting surfaces black or white doesn't make them absorb more or less heat when light is taken out of the equation. Painting a piece of metal black and another white and placing them the same distance from a heat source without light, they both stay thermally identical. Remove the heat source, and exchange it for a light, the black surface will become a heat source itself while the white surface stays nice and cool. And another basic law of physics that applies allot these explanations overlook is that energy can be neither created nor destroyed, only transferred or transformed. Which means equal light hitting the two surfaces means equal force upon both from the photon pressure, and it can't reflect all of the energy and still have an equal force as hit it exerted as momentum. The only way for it to exert equal pressure forwards and backwards is if half the initial pressure is reflected and half transferred to kinetic, which means for every one unit of pressure on the white surface, half is reflected and half absorbed, and for every one unit of pressure on the black surface, one is absorbed and none is reflected. Which means there is at least twice the pressure pushing at the black surface as the white. An answer that disobeys basic universal laws of physics is wrong, because those laws are the foundation of science. You can't ignore the basics, especially when the basics prove a theory wrong.
Any Element that has a dominate Nuclear Right Hand Spin is dominantly North-Polarity and any Element that has a dominantly Left-Hand Spin is a South Polarity. When freezing a Right-Hand Spin Element, it will change the directional Nuclear Spin and become a South-Polarity, as will a Left-Hand Spin Element, will go from a South-Polarity to a North-Polarity when very cold. This is why the Crookes Radiometer changes the direction of its Spin, when made to be cold. Robert Shrewsbury March 11/2022
My father bought me one before I was a teenager (now 54). Recently I found one in Goodwill and snagged it up. If I remember correctly his explanation was the light was reflected off the white/silver and struck the black which absorbed it and pushed the blade.
It has to do with the Poynting and Radiation Pressure. If you can borrow from your library An Introduction to Modern Astrophysics by Carrol and Ostlie it explains it on page 66-67. S(W*m^-2)= (1/u ̥ )*E x B (that is cross not multiply) = (1/2u ̥ )*E ̥ B ̥ F(radiation absorption) = ((A)/c)*cos θ F (radiation reflection) = ((2A)/c)*cos^2 θ
Uh... unless by (4:10) "the vane spins around with the dark side leading" you mean "with the dark trailing," you concluded with the opposite of what Crookes radiometers do. Anyone reading this: Please check videos on other pages that pop up around this one.
If the explanation is correct it should work poorer with less air and better with more air. There is solar wind and solar sails is there not? Why do you not present the more/air models to address this.
More air means more resistance and also more particles to heat so more energy is needed. Since the energy intake is based on the size of the vanes, I guess there's a maximum amount of air for a given vane size, but who knows. I think it's strange how this has been ignored for over a hundred years, as you say, there are a lot of variables that could be tested like the amount of air, the amount of vanes, the vanes shape, color and material. The explanation he gives is actually just the most accepted theory but no one has come with hard numbers and formulas. There are still a lot of things to be done in physics.
So according to your explanation if I set a 45% peeled potato in a perfectly rectangular shaped mithril bowl that is made of carrots the dogs will suddeny appear and hail the unstoppable swirl of the blue puppet.
Reynolds found that if a porous plate is kept hotter on one side than the other, the interactions between gas molecules and the plates are such that gas will flow through from the cooler to the hotter side. The vanes of a typical Crookes radiometer are not porous, but the space past their edges behaves like the pores in Reynolds's plate. On average, the gas molecules move from the cold side toward the hot side whenever the pressure ratio is less than the square root of the (absolute) temperature ratio. The pressure difference causes the vane to move, cold (white) side forward due to the tangential force of the movement of the rarefied gas moving from the colder edge to the hotter edge. Thank you Wikipedia.
AMAZON $15 NOT $64 AS SOME ARE TRYING TO SELL IT FOR AND MY TWO RADIOMETERS HAVE MAGNESIUM WHITE NOT SILVER ON THE VANES AND DARK BLACK ON THE OTHER SIDES
Regarding magnesium: The electric energy required to magnetize an iron bar is much less than the energy required for the magnetized bar to hold itself up against the underside of a steel table for an extended period of time. What is the source of that additional energy?
+Krisgun Chirasanta If that is true, then how does a solar sail work? "The total force exerted on an 800 by 800 meter solar sail, for example, is about 5 newtons (1.1 lbf) at Earth's distance from the Sun,[2] making it a low-thrust propulsion system, similar to spacecraft propelled by electric engines." *src:* en.wikipedia.org/wiki/Solar_sail
Not right. Apart from what 1337wOn is saying... If the thermal theory is right then that would mean that the lightmill would spin faster in air than in partial vacuum, because even if there would be more air resistence there would also be more pressure on the black sides.. but this is not the case since it needs a certain degree of vacuum to work.
You might want to take care saying Crooke didn't just cry witchcraft because he was a true scientist. While he was definitely a scientist who contributed a good deal to the scientific community, he also spent a good chunk of his life trying to prove the legitimacy of spiritualism and the ability to communicate with spirits through mediums. He actually used his radiometer to see if spirits were present. Not quite witchcraft, but not really science either. Luckily, he abandoned spiritualism later in life and got his head back in the game.
Wonderful explanation. Finally understood the concept derived by MR Reynold. Do u know the theoretical background of thermal creep or where to find it? Would really help with my research on this! Thank you.
either that theory is a bit misexplained in this video or it is wrong. you said, quoting: "(...) sending colder air on the silvery side around to the darker side to cool it off (...)" But as far as i know, hot particles would be the ones moving to the colder part and not the other way around...
I bought a radiometer and noticed that too. So theoretically, the vanes should spin in different directions, depending on if they are in a good vacuum or a poor vacuum. Has anyone ever tested this?
Mr frostscience, I think that your explanation is the same, the difference is only the perspective, the video was analysing the contact with the air from a thermodynamic view (when they talk about the pressure and the force of pressure that push the little pieces of papers) and what you said is just an explanation of what happen at the microscopic level.
so its a thermal rotor . what temprarure between cold and hot would it be in thermal equilibrium. Im on the Celcius, 0 Celcius is freezing point and 100C is cooking point . is there any temprature the rotor is completely still ?
I had to disagree with this hypothesis The heat transfer causes it to move. Because you can have a super hot red light aimed at it and it won’t move. You can have a green light orange light and it won’t move. The crooks radiometer only moves when ultraviolet light is involved. If you have a crooks radio meter shine a ultraviolet light at it and watch how fast that sucker will spin.If you have a crooks radio meter shine a ultraviolet light at it and watch how fast that sucker will spin. Light is life, sound and lights are the same if you don’t agree you should really look into sono luminescence & biblical cosmology. Or just research the mud flood ;) thank me later
CROOK’S RADIOMETER THE invisible waves that fill the ethers. you think you can see light, but only its reflection or its source. light itself is invisible. and yet, it moves. to see the invisible is to see Source.
Ok, this makes sense, but what is the practical application for this? I have memories of seeing Crookes Radiometers mounted on posts along with a couple of electrical cabinets in roadside installations in rural southern California back in the 1960s or 1970s but I can't find anything that would indicate my memories are correct, or why they would be there, or how their actions/results were recorded or used.
warm air/cold air has no effect in vacuum,,,,,no air! it's all about frequencies in the uv-range and above(photons,magnetising,and several unknown forces we don't know yet),,,if i had a lab,i would try it with different metals,or even newest elements out of Mendelyev list.....thats my thinking
the colour of the plate doesn't have anything to do with the rotation you can put any colour you want it will still rotate the pressure inside the bulb is the raison for that rotation
My Grandmother has had one of these in her window for as long as I can remember. I always thought it showed the way the wind was blowing...guess I was WAY off. 🤦🏼♀️🤷🏼♀️
if the thermal creep explanation was correct ....then red light would also have turned it cause it gives more infrared signature ...but it doesn't ... only purple and white light does ...check ur facts
But somehow it gets proof that in a perfect vacuum the vanes will rotate due to light impact or "pressure" crookes was right in the end... Maybe astronauts finally made the proof in the perfect vacuum of the space I guess...
thats wrong like has capacitance being that light is a coaxial circuit with dielectric pluses.... that's why if you shine a red light at it it won't spin but if you shine a violet light it will.. Violet has a higher capacity and stand read along the EM spectrum.... or if you shine a bit of sunlight on it since Sun contains everything in the Spectrum if you don't believe me watch this video....
I have just bought one from Germany, so mine spins clockwise, do they all do this! I live in New Zealand and this may have something to do with the fact that water emptying from a sink is opposite from the northern hemisphere, or does it make a difference if the light and dark panels on the light mill are or the left or the right
i'm building one, a light bulb, a standard lamp base, and ? ... foil i guess... blackened one side, cut into squares is ee, and a vaccuum setup... hmmm.... like one from automotive? how many mg/Hg ? help!
hmmm this reminds me of the classic steam engine principle of expanded gases pushing out to do work, the hot air heated strong by the dark vanes expand and as a result attempts to move to the cooler area with light vanes, as this happens, the cooler air also get displaced by the hot air entering the light vane area and ends up on the dark vane and get even hotter and this process repeats over and over again..im assuming if the tube was 100 percent vacuum this turn effect may not work??? lets make a gigantic crookes tube and fix an alternator on its axis and produce some really powerful electric energy ..new meaning to solar energy
This is closer to how I understood it. The black side gets hot and any air molecules that touch it draws off heat by conduction. That air molecule now possesses more kinetic energy in the form of Brownian Motion and kicks away from the vane with more force. The black side gives up energy more readily than the silver side.
Thanks. I saw another linking momentum of light particles to such movement and it just didn't seem true to me. I suspected thermal. Thanks for the info. Cheers
If the thermal creep explanation were correct, then the spinning would eventually stop, when the heat exchange from the radiating surface and the source of light on the light Mill reached equilibrium. This is not what we observe. Further, the phenomenon would grow weaker with a thinner atmosphere, not stronger.
There's a deeper and fuller explanation here if you're interested. A vid done by someone with more equipment, it shows some good observations using specialist equipment. Thanks and Cheers th-cam.com/video/r7NEI_C9Yh0/w-d-xo.html
@Marko Laaksonen What you can do is type "Crookes Radiometer" in the TH-cam searchbar and watch all the videos. Remember that I said nobody gives the right explanation so far. It is not hot gas moving towards the cold gas. Correct theories should predict all observed results from the different experiments, but they don't.
"The dark side leading the way..." If the black side was being pushed, the silver side would "lead", because the black would be on the back. Do I have this backwards?
If the thermal creep explanation were correct, then the spinning would eventually stop, when the heat exchange from the radiating surface and the source of light on the light Mill reached equilibrium. This is not what we observe.
What's the answer then?
@@Josiah_Harder light makes it move
The explanation is wrong. Tesla's ideas on radiant energy and his magnifying transformer were based off what is happening in the crookes radiometer. It rarified air in the glass. Very low oxygen (aether). Just like the upper atmosphere. A pure vacuum makes the veins not spin. Shine a laser on the black vein you get no movement. Pour hot water on the glass and it spins. Tesla said he developed a motor thousands of times more powerful than the Crookes radiometer.
Lol, your graphic when spinning was rather confusing. it was impossible to tell which way you meant it to be spinning.
I still dont get which way the rotor turned.. Maybe use arrows.
Catastrophic error in explanation. If he'd stopped the rotation halfway and then reversed it, it would have been more correct, but it would be hard to tell with a side vide like that. Or he could have just had a video of one rotating on that green screen behind him.
This explanation isn't entirely accurate. The "thermal creep" is a _symptom_ of the fact that the veins are moving; it is not the _cause_ of the movement of the veins. It actually works like this:
*(1)* More EM radiation (in the light spectrum and short-wave infra red) is absorbed by the black side of the veins.
*(2)* The black side of the vein re-emits longer wavelengths of infra red which are absorbed by air molecules near the surface of the vein, causing thermal expansion.
*(3)* The pressure differential causes the veins to be "pushed" with the black face trailing, since this is the side with slightly higher air pressure.
*(4)* The air from the white side will obviously be seen creeping to the black side, since this is what happens when you move ANYTHING through air.
_Also, the air pressure needs to be low enough such that the veins can move freely without much resistance, but not so low that there isn't enough air to be heated by the longer wavelengths of infra red being emitted by the black surfaces._
+Jim Griffiths You are wrong. Maxwell discovered that the warmer gas would simply expand in such a way that there would be no net force from this effect, just a steady flow of heat across the vanes. You must focus attention not on the faces of the vanes, but on their edges. The faster molecules from the warmer side strike the edges obliquely and impart a higher force than the colder molecules.
@Electrical equipment TAO these things and speed of vanes and pressure differential temperature these are all the function of frequency of electromagnetic waves
It's all about Bernoulli effect, the dark side getting heat faster so the air near this side is hot and it expand means more pressure and it push it, and if we put it in cold refregirator let's say, the dark also getting more cold and there will be less pressure so it will be sucked and rotate the otherway around..
I would like to add a hypothesis. If the black side absorbs light it gets warmer. That means the molecules making up the black surface vibrate faster. Now when a gas molecule randomly touches the black surface, some of the kinetic energy of the surface is given off to the air molecule (bouncing it off, speeding it up, raising it's temperature). So it pushes the air molecule away, and the equal and opposite reaction is that the air molecule pushes just as hard on the black surface. It is like if you push someone away from you, it causes you to also move away from them.
Just got one. This thing spins really, really fast in direct sunlight. Also tried my NiteRider 700 lumen bicycle light on it. Makes it spin like mad. The strobe mode makes it spin and look oh so cool.
Lose the shirt Josh, I can't stop staring at your pocket!
Yeah. That was a dealbreaker for me too.
If Crooke had the means of creating a full vacuum, he would have figured that out.
But its worth noting that his theory about "light pressure" wasn't completely incorrect. Although photons have no mass, they do have momentum. But harnessing that kinetic energy would require an enormous and highly reflective surface area. It wouldn't be very practical for terrestrial applications. It's more useful to absorb the photons with solar panels and harness their energy that way.
Physicists are obviously charlatans. If momentum is defined as mass x velocity, and a photon's mass is zero, then for its momentum to be non-zero would require infinite velocity. Hoist them all! Host them all by their own petards!
BrightBlueJim Good point! Just keep in mind that the laws of physics that govern massless particles (and light speeds) are very different from those that govern massive particles. Newtonian equations like E=1/2mv^2 and P=mv fail to paint the whole picture since they fall apart when m=0. Einstein discovered an equation that paints a much bigger picture: E^2 = P^2 c^2 + m^2 c^4
With this we can see that a particle with no mass (m=0) will still have both energy and momentum: E=Pc
Matter that is stationary and lacks momentum (P=0) will of course still have energy as well: E=mc^2
Notice that no particle can ever have both 0 mass and 0 momentum. If both m=0 and P=0, then E=0. This only describes nothingness. Interestingly enough, this is why photons are forced to remain in motion. Since they already have 0 mass, they are never allowed to have 0 momentum.
BrightBlueJim Well said!
how can something have momentum without mass?
what nonsense.
@@ultravidz they are theories not laws and they govern nothing, equations are not reality.
You have part1 of thermal creep backwards. Hot goes to cold, 2nd law of thermo. The energy is radiated from the black side to the molecules causing them to heat up and become excited. These molecules bounce around more frequently on the dark side than on the light side. This is typically referred to as pressure. Because they are bouncing more often, they are striking the surface of the fan more on the dark side than the light. It's this difference in pressure that cause the fan to spin.
That's the direction of conduction, however, we're dealing with fluid density and cold fluid is denser than warm. The colder gas (fluid) will rush to fill voids caused by warmer, low density gas.
I've inherited one from my Dad he had for MANY years. It is a beautiful one but I never knew what made it work other than the sunlight. Wonders of the internet search! Thanks for en"light"ening me!
I thought for quite some time that it was the mass of photons striking the dark side, propelling it, like a solar sail but it also left me wondering. Your explanation fills in the gaps. Thank you.
How can air particles be pushing the vanes? The inside of the bulb is at a near vacuum -- actually 7 torr (0.135357 psi). That means the air is spaced out with ~1 cm of separation between them inside the bulb. Hardly enough air to do much at all... if you could see the molecules you could count them!
.
Still seems to me that black side of the vane is pushed by light pressure (photons transferring kinetic energy to the dark side of the vane) to the tune of about 17 micrograms per 50watts of light energy. That is a small push but the kinetic energy builds until the vane begins to move and then it builds momentum. The reflective side of the of the vane reflects the light photons and kinetic energy is not transferred to that side. I think the inventor was correct.
the pressure hitting the white surface is split, half remains inertial and half is reflected, imparting less momentum than all of it being kinetic on the black face which doesn't reflect. And basic physics says it will spin in the direction the most pressure is exerted with the least pressure directivity providing resistance. Let's not forget the basics here. Just because white reflects doesn't mean it is absorbing more kinetic energy, it actually doing the opposite and absorbing less because half of it is reflected. And the very same amount is hitting the black surface as well, of which none is being reflected.. This is represented as 0.5p+-0.5p for the white surface, half the pressure absorbed and half of it reflected, canceling each other out essentially, but is mathematically represented as the half pressure being reflected by 1p over 2, or 1p/2, as half the pressure is absorbed and half is reflected. And on the black surface it's 1p/1, because the pressure is only going one way. So, the determining factor of spin direction is calculated as white face pressure minus black face pressure (or vice versa) as (1p/2)-1p=.5p-1p=-0.5p on what face spins bias. But let's ignore the most basic laws of physics that nothing can violate because it doesn't suit the theory and call it science when science is actually proving or disproving theories based on the principles of facts rather than belief or bias. If you are ignoring factors that don't suit your hypothesis, that is belief science, aka broscience, and not actual science at all. And ignoring the most basic laws and formulae of physics because they don't suit a theory is belief science, broscience, because you ignore basics that don't suit your theory and have thus traveled outside the realm of science and into the territory of religion. A theory is a guess, not a belief. And approaching science with belief is not science. Science is the process of proving one's guess either right or wrong, not proving it right because you believe in it which means it can't possibly be wrong because that would mean you were wrong. Science is taking it with a grain of salt and forming a new theory when one is proven wrong. Broscience is overlooking what contradicts your belief because you are so determined to prove it right because of your belief. Belief and science don't mix, approaching science on a belief never proves a thing because you refuse to accept the facts. Knowing is acceptance based on fact, and science is about knowing. Belief is about taking things based on faith or lack of proof, and lack proof is proof on nothing, as well as belief being the territory of religion and far from science. Ignoring the facts because you chose blind faith in your theory is not going to change the facts. Just because you can't eat an elephant in one big complicated bite doesn't mean you can't eat in a simple bite at a time. You can't skip steps or overlook facts, and you have at least three proofs of your own misunderstanding of why it isn't heat in this video by the way.
Good explanation! I just obtained my first Crooke’s Radiometer and was attempting to learn exactly how it works, and doesn’t work (an interesting story in and of itself). After reading several different explanations - including, surprisingly, some erroneous ones - I understood the mechanism best after seeing this video.
Except it's not. Basic Physics says half the photon pressure on the white face is reflected while all of the pressure on the black is absorbed, meaning the black face get's twice the pressure of the white face. It really is Photon Pressure. And removing the glass lens around it proves it, because if the heat source in the vacuum chamber at the same pressure with the vane, heat has no effect on it until it starts escaping through the tank, and then it spins backwards as photon pressure is released by the excitement of photons as heat passes through the glass in the opposite way, pulling photons out and exerting the opposite photon pressure on the veins, the white giving off more than the black thus leading the opposite way. And that is because without a lens between the heat source and the vane there is nothing to cause the heat to agitate photons into moving light. Never skip the basics, even the most basic taken for granted basic, and never take the basics for granted, because without the basic concepts, the complex ones fall to pieces, because complexity is essentially a stacking of basics. In fact the term critical thinking applies to the application of Occam's Razor. The simplest, or most basic, of solutions is often the best. And even the most complex puzzles have the simplest solutions. It's not about heat, but rather it really is about the photon pressure, or light pressure, an equal and opposite reaction on both surfaces. Equal pressure applied, unequal reaction to it. And let's not forget painting surfaces black or white doesn't make them absorb more or less heat when light is taken out of the equation. Painting a piece of metal black and another white and placing them the same distance from a heat source without light, they both stay thermally identical. Remove the heat source, and exchange it for a light, the black surface will become a heat source itself while the white surface stays nice and cool. And another basic law of physics that applies allot these explanations overlook is that energy can be neither created nor destroyed, only transferred or transformed. Which means equal light hitting the two surfaces means equal force upon both from the photon pressure, and it can't reflect all of the energy and still have an equal force as hit it exerted as momentum. The only way for it to exert equal pressure forwards and backwards is if half the initial pressure is reflected and half transferred to kinetic, which means for every one unit of pressure on the white surface, half is reflected and half absorbed, and for every one unit of pressure on the black surface, one is absorbed and none is reflected. Which means there is at least twice the pressure pushing at the black surface as the white. An answer that disobeys basic universal laws of physics is wrong, because those laws are the foundation of science. You can't ignore the basics, especially when the basics prove a theory wrong.
2 more vids from u and my head has exploded 100 times.
Not again -.-'
Any Element that has a dominate Nuclear Right Hand Spin is dominantly North-Polarity and any Element that has a dominantly Left-Hand Spin is a South Polarity. When freezing a Right-Hand Spin Element, it will change the directional Nuclear Spin and become a South-Polarity, as will a Left-Hand Spin Element, will go from a South-Polarity to a North-Polarity when very cold. This is why the Crookes Radiometer changes the direction of its Spin, when made to be cold. Robert Shrewsbury March 11/2022
I need to get one of these for my science class next year. It’s a good demonstration of the flow of energy
My father bought me one before I was a teenager (now 54). Recently I found one in Goodwill and snagged it up.
If I remember correctly his explanation was the light was reflected off the white/silver and struck the black which absorbed it and pushed the blade.
What a score!
I remember someone in our neighborhood had 2 of these in their window. I often stopped and watched it for some time.
This device is one of my favorite, I happen to have one of these.
Know how to make a Crookes' radiometer run backwards? Think saturation.
Cool it. To see check out this video: m.th-cam.com/video/r7NEI_C9Yh0/w-d-xo.html
It has to do with the Poynting and Radiation Pressure. If you can borrow from your library An Introduction to Modern Astrophysics by Carrol and Ostlie it explains it on page 66-67.
S(W*m^-2)= (1/u ̥ )*E x B (that is cross not multiply)
= (1/2u ̥ )*E ̥ B ̥
F(radiation absorption) = ((A)/c)*cos θ
F (radiation reflection) = ((2A)/c)*cos^2 θ
Uh... unless by (4:10) "the vane spins around with the dark side leading" you mean "with the dark trailing," you concluded with the opposite of what Crookes radiometers do. Anyone reading this: Please check videos on other pages that pop up around this one.
Great explanation! Thanks!
If the explanation is correct it should work poorer with less air and better with more air. There is solar wind and solar sails is there not? Why do you not present the more/air models to address this.
More air means more resistance and also more particles to heat so more energy is needed. Since the energy intake is based on the size of the vanes, I guess there's a maximum amount of air for a given vane size, but who knows. I think it's strange how this has been ignored for over a hundred years, as you say, there are a lot of variables that could be tested like the amount of air, the amount of vanes, the vanes shape, color and material. The explanation he gives is actually just the most accepted theory but no one has come with hard numbers and formulas. There are still a lot of things to be done in physics.
More air would cause too much wind resistance, the rotation would be less spectacular.
So according to your explanation if I set a 45% peeled potato in a perfectly rectangular shaped mithril bowl that is made of carrots the dogs will suddeny appear and hail the unstoppable swirl of the blue puppet.
I immediately have the idea of the answer the moment he said partial vacuum.
Reynolds found that if a porous plate is kept hotter on one side than the other, the interactions between gas molecules and the plates are such that gas will flow through from the cooler to the hotter side. The vanes of a typical Crookes radiometer are not porous, but the space past their edges behaves like the pores in Reynolds's plate. On average, the gas molecules move from the cold side toward the hot side whenever the pressure ratio is less than the square root of the (absolute) temperature ratio. The pressure difference causes the vane to move, cold (white) side forward due to the tangential force of the movement of the rarefied gas moving from the colder edge to the hotter edge. Thank you Wikipedia.
AMAZON $15 NOT $64 AS SOME ARE TRYING TO SELL IT FOR AND MY TWO RADIOMETERS
HAVE MAGNESIUM WHITE NOT SILVER ON THE VANES AND DARK BLACK ON THE OTHER SIDES
Thermodynamics and air convection make perfect sense especially considering it's in a vacuum. Good video :)
Regarding magnesium: The electric energy required to magnetize an iron bar is much less than the energy required for the magnetized bar to hold itself up against the underside of a steel table for an extended period of time. What is the source of that additional energy?
Dude thank you....helps me figure out my idea
Just bought one ☝️I think 💭 It’s Neeto! Man! And a little bit Groovy!😎😬
Crookes Radiometer is a good basis to Tesla's free energy apparatus
Does a Crooks radiometer fail to spin in a pure vacuum??
+zeffur7 it does, not enough air molecules to push it
+Krisgun Chirasanta If that is true, then how does a solar sail work?
"The total force exerted on an 800 by 800 meter solar sail, for example,
is about 5 newtons (1.1 lbf) at Earth's distance from the Sun,[2] making it a low-thrust propulsion system, similar to spacecraft propelled by electric engines."
*src:* en.wikipedia.org/wiki/Solar_sail
It still spins, even in a vacuum.
@@1337w0n it will only spin in a vacuum if it is able to overcome the friction of the spindle.
U guys explain things so well I love watching your vids
What's with that shirt???
batmmannn
Looks like they ran out of blue cloth when making and chose some spare scraps instead.
Not right. Apart from what 1337wOn is saying... If the thermal theory is right then that would mean that the lightmill would spin faster in air than in partial vacuum, because even if there would be more air resistence there would also be more pressure on the black sides.. but this is not the case since it needs a certain degree of vacuum to work.
You might want to take care saying Crooke didn't just cry witchcraft because he was a true scientist. While he was definitely a scientist who contributed a good deal to the scientific community, he also spent a good chunk of his life trying to prove the legitimacy of spiritualism and the ability to communicate with spirits through mediums. He actually used his radiometer to see if spirits were present. Not quite witchcraft, but not really science either. Luckily, he abandoned spiritualism later in life and got his head back in the game.
Interesting
thank you for explaining!
You've got to ask yourself why there was no video of a Crookes Radiometer in this video about Crookes Radiometer? LOL Still, great video.
This guy should do voice work for a cartoon show. He's too freaking awesome!
You're right, but you haven't explained why the vanes get electrically charged, though. This is something few people have noticed...
And, the black side isn't "LEADING" it's pushing. :)
Is it just me or according to the explanation, more pressure on the dark side pushing on it, wouldn't it the lead withe shiny side?
No pressure in a vacuum
Wonderful explanation. Finally understood the concept derived by MR Reynold. Do u know the theoretical background of thermal creep or where to find it? Would really help with my research on this! Thank you.
if heat causes the vane to spin, then can i use hair dryer to check if it's true?
yes, it does work
either that theory is a bit misexplained in this video or it is wrong.
you said, quoting: "(...) sending colder air on the silvery side around to the darker side to cool it off (...)"
But as far as i know, hot particles would be the ones moving to the colder part and not the other way around...
Show us a thermal video to prove us the "heat theorie" to spin the radiometer please!
Awesome explanation. Even a non-science guy like me understood perfectly.
I bought a radiometer and noticed that too. So theoretically, the vanes should spin in different directions, depending on if they are in a good vacuum or a poor vacuum. Has anyone ever tested this?
Mr frostscience, I think that your explanation is the same, the difference is only the perspective, the video was analysing the contact with the air from a thermodynamic view (when they talk about the pressure and the force of pressure that push the little pieces of papers) and what you said is just an explanation of what happen at the microscopic level.
It can even detect the light from your hands
What happens if you use a laser? Do the dark and light sides respond differently? Does the color of the laser make a difference?
so its a thermal rotor . what temprarure between cold and hot would it be in thermal equilibrium. Im on the Celcius, 0 Celcius is freezing point and 100C is cooking point . is there any temprature the rotor is completely still ?
I don't tend to leave comments but this guy was really cool!!!
I had to disagree with this hypothesis The heat transfer causes it to move. Because you can have a super hot red light aimed at it and it won’t move. You can have a green light orange light and it won’t move. The crooks radiometer only moves when ultraviolet light is involved. If you have a crooks radio meter shine a ultraviolet light at it and watch how fast that sucker will spin.If you have a crooks radio meter shine a ultraviolet light at it and watch how fast that sucker will spin. Light is life, sound and lights are the same if you don’t agree you should really look into sono luminescence & biblical cosmology. Or just research the mud flood ;) thank me later
I get it, but what's the practical purpose of a radiometer other than a toy or a demonstration device for thermal creep?
CROOK’S RADIOMETER THE invisible waves that fill the ethers. you think you can see light, but only its reflection or its source. light itself is invisible. and yet, it moves. to see the invisible is to see Source.
Ok, this makes sense, but what is the practical application for this? I have memories of seeing Crookes Radiometers mounted on posts along with a couple of electrical cabinets in roadside installations in rural southern California back in the 1960s or 1970s but I can't find anything that would indicate my memories are correct, or why they would be there, or how their actions/results were recorded or used.
Or just use solar panels instead...
Which is the dominant force acting on the fans - conduction or convection?
What would happen if we took crooks radiometer to the ISS for experimentation? Would microgravity have an effect on it?
I honestly thought it was caused by light "pushing" the object. It does work.. hence the solar sails, but i dont think is that strong.
warm air/cold air has no effect in vacuum,,,,,no air! it's all about frequencies in the uv-range and above(photons,magnetising,and several unknown forces we don't know yet),,,if i had a lab,i would try it with different metals,or even newest elements out of Mendelyev list.....thats my thinking
😂😂 *He could shout out Witch craft, Witch caft which he had under his bed*
Great video. Would have been better if it showed a real radiometer instead of the drawn one.
the colour of the plate doesn't have anything to do with the rotation you can put any colour you want it will still rotate
the pressure inside the bulb is the raison for that rotation
My Grandmother has had one of these in her window for as long as I can remember. I always thought it showed the way the wind was blowing...guess I was WAY off. 🤦🏼♀️🤷🏼♀️
Bet if you wack this thing in a total vacuum, it doesn't budge an centimeter
The video is great but next time please stop the background music for a clearer listening. Thanks!
Hey can I know if u can convert it into electrical energy using an alternator type setup
if the thermal creep explanation was correct ....then red light would also have turned it cause it gives more infrared signature ...but it doesn't ... only purple and white light does ...check ur facts
But somehow it gets proof that in a perfect vacuum the vanes will rotate due to light impact or "pressure" crookes was right in the end...
Maybe astronauts finally made the proof in the perfect vacuum of the space I guess...
So if we make a good enough vacuum, it will not work.
That would suck though, wouldn't it?
Yea, it sure would. Rats.
can we, based rotations per minute, measure radiation with this device? Does it provide rotation per minute?
thats wrong like has capacitance being that light is a coaxial circuit with dielectric pluses.... that's why if you shine a red light at it it won't spin but if you shine a violet light it will.. Violet has a higher capacity and stand read along the EM spectrum.... or if you shine a bit of sunlight on it since Sun contains everything in the Spectrum if you don't believe me watch this video....
Video link missing.
So it wouldnt work if there was no gas at all inside... The rotor is sucked along with the black side pulling the rotor around ?
it was a good explanation. thanks
I have just bought one from Germany, so mine spins clockwise, do they all do this! I live in New Zealand and this may have something to do with the fact that water emptying from a sink is opposite from the northern hemisphere, or does it make a difference if the light and dark panels on the light mill are or the left or the right
the panels are the differentiating factor. Not on which side of the earth you are on, which wouldn't change the way physics works.
Crookes was a spiritualist, and believed in ghosts or spirits. So I would guess that he could attribute it to spirits then.
I think this damaged my childhood.
it is witch craft because the time period matches an only witches have cool names like crook or osborn
I want to see josh build one!
If this is true then this device should turn under normal atmospheric pressure. But as I know the device don't work under atmospheric pressure
Normal atmosphere has too much air. it will resist the movement
i'm building one, a light bulb, a standard lamp base, and ? ... foil i guess... blackened one side, cut into squares is ee, and a vaccuum setup... hmmm.... like one from automotive? how many mg/Hg
? help!
So basicly we know how to turn heat into energy but we dont do it?
I wonder why that is
@@sphiweposeka6970 $$$$$$$
hmmm this reminds me of the classic steam engine principle of expanded gases pushing out to do work, the hot air heated strong by the dark vanes expand and as a result attempts to move to the cooler area with light vanes, as this happens, the cooler air also get displaced by the hot air entering the light vane area and ends up on the dark vane and get even hotter and this process repeats over and over again..im assuming if the tube was 100 percent vacuum this turn effect may not work??? lets make a gigantic crookes tube and fix an alternator on its axis and produce some really powerful electric energy ..new meaning to solar energy
This is closer to how I understood it.
The black side gets hot and any air molecules that touch it draws off heat by conduction. That air molecule now possesses more kinetic energy in the form of Brownian Motion and kicks away from the vane with more force. The black side gives up energy more readily than the silver side.
hi nice to visit this comment again after 5.yrs...cheers
@@fidelcatsro6948
imgs.xkcd.com/comics/duty_calls.png
@@jsl151850b hahaha
Isn't the dark side "following"?
Cran Cowan Yes - he is wrong. The silver side is leading, the black side is following. I have one here so it is not theory...
"Trailing" is how they would say it in aviation.
3:20 - that a dump phrase "nature sending air to hot regions to cool it donw" ?? WTF man???
Fact is moonlight will make surfaces cold. Fact
Thanks. I saw another linking momentum of light particles to such movement and it just didn't seem true to me. I suspected thermal. Thanks for the info. Cheers
If the thermal creep explanation were correct, then the spinning would eventually stop, when the heat exchange from the radiating surface and the source of light on the light Mill reached equilibrium. This is not what we observe.
Further, the phenomenon would grow weaker with a thinner atmosphere, not stronger.
There's a deeper and fuller explanation here if you're interested. A vid done by someone with more equipment, it shows some good observations using specialist equipment. Thanks and Cheers th-cam.com/video/r7NEI_C9Yh0/w-d-xo.html
But can you explaine why it spins when you put an ice cube on top of it?
An why in that direction?
@Marko Laaksonen You have to explain why 'being tranferred' makes it move.
Remember that nobody gave the right explanation so far.
@Marko Laaksonen My old professor will get the Nobel for it.
@Marko Laaksonen What you can do is type "Crookes Radiometer" in the TH-cam searchbar and watch all the videos.
Remember that I said nobody gives the right explanation so far.
It is not hot gas moving towards the cold gas.
Correct theories should predict all observed results from the different experiments, but they don't.
@Marko Laaksonen Keep trying, but watch "all" videos first.
(The Science Asylum)
(The Action Lab)
etc...
@Marko Laaksonen Weigh every word, idea and assumption very well.
"The dark side leading the way..."
If the black side was being pushed, the silver side would "lead", because the black would be on the back.
Do I have this backwards?
Crookes Radiometers fuckin' rule!!!!!!!!!!!!!
can you tell me please by which material the wings are made.
Thanks, great explanation
"...is explained once and for all, by MMMME." >:D
Crookes Radiometer is witchcraft lol
so there is no air and it moves because of air. ETHER
Do you not mean to say the dark vain gets warmer thus pushing the air away, moving itself?