The magnet is stopping due to Lenz's law. Basically, the moving magnet is creating a magnetic flux. The law states that any change in flux (in this case, it's creation through spinning) will work to counteract the change. So, the spinning magnet is creating Eddy currents which cause the magnet to stop spinning.
SixThough, That's a great idea. A spherical or cylindrical magnet should work better. SquidCaps, The north and south poles of the magnet are at the top and bottom, so aliment wouldn't make sense.
hkcute; Flux isn't the issue. Its the second time and spatial derivatives of the magnetic vector potential which induces an opposite (eddy) current density. And yes, if it was perfectly homogenious a spinning cyllinder wouldn't induce any eddy currents in a plane purpendicular to its axis, but you won't find any sufficiently perfect magnet for that to actually work. Zigi Samblak; At the (pretty bad) level of vacuum that he could generate, air resistance would be orders of magnitude weaker than the electro-magnetic losses. In other words, it would stay spinning for literally hundreds of minutes if air resistance were the ONLY loss mechanism.
Cody'sLab; It does increase the circularly induced eddy currents (kind of like a magnetic stirrer works). Asymmatry in the same plane as the conductor is bad news, but since you have a pretty substantial conductor in all 3 dimentions (and the entire vacuum chamber would also have a BIG effect, even though it is relatively far away - see Gauss' Law for charge screening), ANY deviation in the up-down direction would also cause quite a lot of enegy loss in those modes.
A round/disc magnet will have a axially symmetry magnetic field, if you rotate about the axis of symmetry the magnetic field doesn't change and so you can eliminate the eddy currents. To reduce the faraday disc effect you'd need to use only diamangetic levitation but i'm not sure of the relative strength of these effects. A square magnet doesn't have a axially symmetrical magnetic field. Also you could just use polycardon which has a larger diamagnetic effect than bismuth but might be difficult to get a large enough sample.
MrEvilchickens the problem I see is finding a round magnet that is accurately symmetric enough. Without that, it will spin slanted (as the square magnet in the video) and have symmetry defects, which will end up with the same result (albeit maybe a slightly longer spin duration)
My hypotheses for why it stopped (in order of likelihood) are: 1) Eddy currents and magnetic resistance 3) Earth's magnetic field 2) Earth's gravity 4) Not a perfect vacuum The solution: Use superconducting magnets in a perfect vacuum, in intergalactic space.
Has basicallybeen done, in the Gravity Probe B - Mission. Except they did it in an orbit around the earth, because gravity causes no friction, this difference does not matter. They levitated spheres coated in a superconductor cooled to 2K in a vacuum surrounded by superfluid helium, surrounded by a superconductor.
Wait...that makes so much sense. And even if he had a perfect magnet and a non conductive magnetic material, it would still stop because of the earth's magnetic poles.
Not sure if it is the earths magnetic field doing this or not. The question I have is why it unwinds when it stops, then rotates the opposite direction, and continues oscillating until it stops completely. Need to mark the spinning magnet and see if it stops every time in the same position relative the the earths magnetic field to be sure! Or it could be the orientation of the supporting magnetic fields. More testing needs to be done.
External magnetic field applies torque to the magnet, trying to align it's magnetic field. But there is no feedback according to magnet's spin speed, if magnet is not perfectly aligned it just always aplies some torque, until magnet crosses balance point at which torque changes direction. But magnet already got some momentum, it can't instantly stop. So it's continues to rotate after balance point until rotational force accumulates enough and it starts to spin other way. I dont think it's only earth's mangetic field, huge magnet on top must add to it. Maybe, quite a lot. So it will be resultant force.
sandqwert the correct answer is nothing, it will outlast anything, the problem nothing is the concept of the lack of anything, this concept could better be described but human intelligence can only go thus far, nothing was before the universe nothing will be after the universe, thus nothing lasts forever
Christopher Nah it didn't work, it wasn't strong enough as he said. I really like seeing how he sets stuff off with the laser though. I don't know what he could do without that thing.
Why not just hook up that little glass pipe to atmospheric pressure and have a 'vent' valve to push it? I think you could get better spinning with that.
you demonstrated why it won't spin forever, when you attempted to move the magnet to start it spinning. Although, there is no force of friction due to air, the bismuth's irregular shape experiences the magnetic field differently as it spins. this still acts as a type of drag. perhaps if you levitate a more perfect sphere you might see more noticeable effects.
Basically it wants to line up with the Earths magnetic field like a compass. I'm wondering what if you had a magnetic track and a superconductor that you pushed around the track, that will eliminate the magnetic flux, You would then have the issue of keeping the superconductor cold but if it was in a vacuum and levitating then it should stay cold.
I'm so happy you did this because during my physics class in last year we were talking about efficiency of motors due to friction and it got me thinking about this exact situation, I just never had the opportunity to look into this.
I really LOVE these electro-magnetic experiments! You could maybe try casting the bismuth into a circular mould with many thin pieces of plastic acting as insulators (like in transformer laminations). Also, perhaps you could try a non conductive ceramic magnet (AlNiCo and Samarium Cobalt are about equally conductive, with ferrites being MUCH less conductive) as levitation device? You could theoretically even use many small pieces of Neodymium magnets (without the nickel coating of cource) and have them pin a thin insulator between themselves (mica perhaps?).
Eddy currents in bismuth are probably quite low, since it his high electrical resistance for a metal. Copper Electrical resistivity is 16.78 nΩ·m (at 20 °C) or 0.00000001676 Ω·m bismuth Electrical resistivity is 1.29 µΩ·m (at 20 °C) or 0.00000129 Ω·m So if I did my math right bismuth has 76.8 times higher resistance then copper. I'm thinking about making a bismuth tube to drop my 3/4" neodymium magnet through, so i can see how much the eddy currents slow it down compared to dropping it into a copper tube.
There is not much inertia going on in this magnet. By the way, one comment out there pointed out, that if magnetic field would be very axial with center of mass, there would be no change of magnetic field in any point around magnet spinning on same axis. So, +Cody'sLab, could you please check same with spheroidal or, may be, cylindrical magnet, and, may be, huge chunk of copper above it?
Cody, I think the magnet won’t spin forever because it will always point at magnetic north. Correct me if I’m wrong but that’s also why the magnet was favoring facing one side and than swinging back and forth as earths magnetic pull eventually brings it to a stop always facing the same direction.. go get a compass and see if I’m right Cody.
Visually stunning, informative, casual and clean editing; Cody, you gorgeous gangster - this is my favourite video of yours (been a fan since Westminster bees).
i'll risk making this comment before watching to the end of the video, but at 5:30 you can see there is some asymmetry in the magnetic field from the way the magnet seems to ever so slightly lurch into a "stable spot" before climbing back out again and continuing to rotate with slightly less speed.
really ? seems like a good explanation, but i wouldnt have thought the effects of earth's magnetic field would contribute significantly enough to this system, given the much higher field strength of the magnets and bismuth Cody has set up here. Or is that still possible given that the forces from said magnets are mostly cancelled out ? Basically it seems intuitive to me that this would spin a lot smoother and lose much less energy to this fabled stable spot, if the magnet was perfectly balanced and not sagging on one side. Or would it still get stuck on magnetic north in this "perfect" case ?
I think gravity as well as earth magnetic field is just adding sinusoidal wobble to speed. It does slow magnet down half way, but also do speed it up other half.
posysajrazdwatrzy No, the earth's field is at basically 90 degrees to the rotating magnet's field. It's pulling the magnet to flip on its side, not rotate on axis.
Great video, you actually got your answer as to whether or not it would spin forever at 3;00 you can see the magnet oscillating back and forth. Which means there's some kinda force on it.
He could be pulling current out of a magnetic field with the coil, storing it, and then measuring it. Big loop o' wire under a power like will do the trick
Thank you so much for this video Cody. Back in highschool I wanted to research this for my "thesis" but my teacher thought I wouldn't be able to finish it. Now I finally know the outcome!
Cody when you put a microwave in your vacuum chamber it seemed to draw more power. If you put a microwave in a pressure chamber would it use less power ?
Replace the air with a superfluid, maybe depending on your temperature. A fundamental experiment here, I love it! Analogues of this are still "spinning" with superconducting loops.
Since liquid oxygen is being attracted to a magnet and is not metallic, would it be possible to contain the oxygen in some form of container (like your glas tubes) to get rid of eddy currents and stuff? Or would you need a ridiculously huge magnet to lift the oxigen together wit its container?
If I understand this correctly, if there is a little enough amount of radiation then items in a vacuum will just get colder and colder to a certain point (I may have misunderstood), so to that end if the oxygen is frozen and placed in a vacuum then it will stay cold enough to stay solid. Alternatively you can always seal the container and if you keep it cold enough to not expand then you should be good.
Zeibentaul Unless the oxygen gave off a form of radiation, I don’t think it would decrease in temperature in the vacuum chamber. That said, it would expand into a gas, and the atoms might transfer their energy to the container walls (say, a sealed glass tube, not the walls of the vacuum chamber). So the gaseous oxygen may decrease in temperature relative to the increase in temperature of the container. Since all the energy would still be conserved within the system.
Thank you for performing this experiment. I suggested it to another youtuber who plays with vacuum chambers but he totally butchered it in my eyes. This is pretty much exactly what I would have done, provided I had the stuff to try it.
I'm wondering if there is a different factor here: Earth's magnetic field. That would explain a force that causes it to "rock" left and right at the end of the spin.
I'd say that it's possible, but I doubt that it's the only reason. Earth's Magnetic field surely interracts with it, but I also think there's more factors than just that.
The fact that the magnet is slowly oscillating back and forth when it should be at rest, indicates to me that it's not going to spin forever. There appears to be some resistance in the magnetic field itself that the object is "bouncing" off of. It will probably sit there and oscillate for a long time but eventually stop doing that as well.
You could apply an electric field to the magnet above to get the magnet inside the chamber to spin. Eddy currents would slow the magnet eventually, however. It would spin longer than under atmospheric pressure.
Steven Cassidy actually it would not die, it just can’t fly in the chamber, the fly will survive. There is a video of a fly in a gas chamber. Search it up
The magnet induces electricity in all the metal parts around it, which generates an electromagnetic field which counteracts the spin that created it. It's very much like the magnet in a copper tube experiment. Of course, with such a small magnet and such far away and not aligned metal parts the effect is nearly nonexistent, but it does waste some energy, which means that even if all forms of friction were removed the magnet will still eventually stop. Also, generally acquiring perfect steady motion (including rotation) with anything that is magnetic is impossible because of the natural electromagnetic background of the Universe which will always slightly influence it. EDIT: Oh, you've mentioned it. Well, leaving the comment for reference.
Sadly, your comment as useless as me not having yes/no answer before watching video. Second I seen it stopping, I instantly remembered Foucault currents. But i did not made that prediction before i watched. Unless you wrote "why", you didnt really made good, strong prediction. And I didnt, which make's me sad.
morpheus ꀊ I applaud you for being honest and say that u didn't predict it before the video. I as well predicted no, but didn't have a why, neither was I able to have a reason for it.
morpheus ꀊ I know nothing about that current you're talking about. All I know is that perpetual motion are impossible- at the moment, no discoveries to prove it yet. And that's my basis.
There are a number of forces I can think of that may be causing the magnet to stop: - Air flowing in slowly when the pump is turned off - Vertical magnetic currents from the larger magnet, orthogonal to the rotation plane, causing alignment (like the moon has one face locked in position) - The Earth's magnetic field, like in a compass - Hysteresis currents
Why? If someone likes the video in the first few seconds, yt does not count it as a view, until you watch it till the end. Use your common sense before you talk.
Actually, the likes are updated instantly whereas the views are updated after a certain amount of time has passed. Say like every half an hour (As an example, I can't actually remember exactly how long).
That it's rocking back and forth after the first attempt shows that it isn't just air resisting it spinning. Weight distribution or something else, there's a "hump" there that it has to overcome.
i think it will rotate much longer with a round magnetic form like a like a zylinder or a ball. Because the cube had a resistance to the magnetic field.
Get you an MKS SRG, The MKS Spinning Rotor Gauge (SRG) line is a high-vacuum gauge that operates by measuring the amount of viscous drag on a magnetically-levitated spinning ball, which is directly related to the number of molecules in the chamber (i.e. pressure).
I think you would need a perfectly ballanced cube or disk to let it turn longer, because the cube doesn't look's like that. If the cube is nearly at the end of the applied force, it swing's back and forth. Which means that there is a point on the cube lower than all other on the downside, which is affected by gravity.
Hi, Cody. You need to use a spherical magnet instead of a cube. The magnetic field of a cube shaped magnet has components that vary with rotation angle. Rotation of the cube magnet then generates a time-varying magnetic field and this will always induce eddy currents in any metals near the magnet. These eddy currents dissipate energy thermally. This is the energy loss that is damping the rotation of the cube magnet. Since the field of a spherical magnet is unchanging with respect to rotation on its dipole axis, it eliminates the time-varying field components and thereby eliminates the eddy current losses that are damping the rotation of your cube magnet. When using a spherical magnet, the only remaining source of eddy current induction will be due to imperfections in the magnets field due to material defects, but these will be very small effects.
it's pulling in one side, you can see it choosing a fixed position, going back and forward until it finds it. so the magnet is not positioned correctly, it's pulling in several directions at the same time
it still react or lines up into the direction of magnetic poles of the earth like a compass that's why i think it will not really spin forever even if there is no air resistance.
The reason of the stop is lenz lawa, the magnet is inducing a current on the opposite direction hence creating a force to the other, this makes sense because if it where to go on forever you would be essentially making infinite energy
The Earth's magnetic field will also be absorbing energy from the system. Magnetic remanence is another source of loss. Then there's still a little bit of air still inside the chamber. Thanks Cody. Interesting,as always.
Before and during the experiment when it stopped it would then rotated a little in the opposite direction. I also noticed that the speed once it was in a vacuum varied depending on which side it was facing. That tells me that it isn't balanced. Even though it's being levitated it is still subject to the force of gravity. I think the heavy side is a force of friction.
If I recall, the viscosity of air is constant down to about a torr, which is what you pumped down to, so you're probably still seeing significant air resistance effects. You might try with a lower vacuum pressure if your system can do that.
Ferrite cores used in high frequency switching transformers have magnetic properties but have low electrical conductivity, the core material is designed specifically to reduce eddy currents, not sure how well the material would work but it would be interesting to try.
If I remember correctly to limit eddy currents constructors of engines divide the magnet with several thin non conductor slices reducing a lot the area of the circles the current follow so limiting its effect substantially. I may confusing it with some other dissipative effect though.
pressurise that little bulb with the wood in it seal it with wax then melt the wax under vacuum. The Coriolis effect will influence the spin of the magnet. also it doesn't look level. and to a much smaller degree than the Coriolis effect light hitting the magnet will influence it. (Radiometer) BUT they don't work by light bouncing off them as I once though it is actually heat and pressure. Which is why they spin towards the foil part and not towards the black. Balance of the magnet will also effect it.
you know those hand crank flashlights? You feel more resistance the faster you crank them. That resistance is a rotating magnetic field cutting a conductor and inducing current into something. This is the force that stops this magnet
Apparently these magnets (assuming you're using a neodymium magnet) are usually coated with nickel having a 1.4*10^7 S/m conductivity but the neodymium iron boride, despite being a ceramic, has a conductivity of about 1*10^6 S/m. So, probably some of the effects of the eddy currents, which would indeed be on the surface of the magnet, would be somewhat lessened if you removed that coat.
Hey Cody I was about to dive into this. Check this out. Pipe an air compressor into the glass to push the magnet. It has to be a very small amount of air pressure. And your decompresor would have to constantly run. But just for proof of concept in space. This could be it.
My best guess is that this is caused by electromagnetic resistance. The best example i can think of when you crank a hand generator no matter how hard you push it ramps up slowly because of the resistance of the fields interacting with eachother. Basically an electromagnetic form of friction
you should pressurize a fluid then bring it room temp. so that, when it depressurizes it will be about 40 F or "ice cold". in my ap chem class we thought of a soft drink that when you open it, it will depressurize and chill the drink inside so you don't have to chill your drinks.
The magnetic force between the magnets making the levitation makes it slow down like friction. Even if it didn't unless you had a complete vacuum air would slow it down eventually
I think it is the magnet's "compass" behaviour that is slowing it down. As the magnet wants to point north it is periodically accelerating towards it and slowing away from it. Thats why when it is slowing down it will slow and then speed up before slowing again. I imagine doing this experiment a considerable distance away from an active planet's core would work.
powdered iron is used with a binder in RF inductors for exactly the reason you need: minimize eddy currents. It won't be zero but alot better than what you've got now. Also ferrites are used. Google powdered iron toroid or ferrite toroid for example.
ok. first off.. i loved hearing the bees 😂😂 but even though the magnet didn't spin for long, this was still an awesome experiment, and a great watch. the bees knees! 😊😊
You could try embedding a superconductor in solid nitrogen using evaporative cooling. The vacuum would freeze the nitrogen and would simultaneously isolate the whole thing so as long as you keep intense light from it, it would levitate.
Glass is diamagnetic. Not as much as Bismuth...but when the well the magnet floats within is self-centering, the last few spins remind me of torque translation, or putting square wheels on a vehicle over flat ground. At one face especially, it looks like it's climbing a hill, then falling down the opposite side. If I look really carefully, it appears that to be pistoning (up and down) against gravity; spinning in this well looks like work.
Forever is such a strong word... Even in a perfect vacuum (and not just 1/800 of normal air pressure) it would still slow down. Even if you would remove everything you possibly could that interacts with the magnet it would slow down. Very, very slowly but it would still stop eventually. There is always something that will interact with this system. If we assume that the universe will exist for all eternity in some fashion without ever stopping to exist and if we assume that this system can exist in this configuration for all eternity as well, even the tiniest possible influence on it will eventually make it stop spinning. I guess it depends on how you define "forever" :) If you define it as "until no one exists anymore to witness it stop spinning" then I could get behind it. If no one exists anymore to care whether it's spinning anymore or not, I guess then we can say that it did spin forever ;)
Wood doesnt burn in vaccum, and probably there would be induction on the bismuth because it isn't a superconductor replicating identically the magnetic field lines. And the superior magnet would induce a current on the bottom one due to magnetic field flux be changing. Thanks Cody, I aways wanted to see if it worked out, if I had condition I could do the same experimento that you did.
The magnet is stopping due to Lenz's law. Basically, the moving magnet is creating a magnetic flux. The law states that any change in flux (in this case, it's creation through spinning) will work to counteract the change.
So, the spinning magnet is creating Eddy currents which cause the magnet to stop spinning.
RE exactly what I was thinking.I wonder if a circular magnet would spin longer as the circumference will just be moving over the same area
I can bet that the objects ends up aligned north south on earth's magnetic field and that is enough to stop it. It oscillates in the end.
SixThough, That's a great idea. A spherical or cylindrical magnet should work better.
SquidCaps, The north and south poles of the magnet are at the top and bottom, so aliment wouldn't make sense.
Besides that, a perfect vacuum doesn't exist so it would be impossible to completely remove all resistances.
hkcute; Flux isn't the issue. Its the second time and spatial derivatives of the magnetic vector potential which induces an opposite (eddy) current density.
And yes, if it was perfectly homogenious a spinning cyllinder wouldn't induce any eddy currents in a plane purpendicular to its axis, but you won't find any sufficiently perfect magnet for that to actually work.
Zigi Samblak; At the (pretty bad) level of vacuum that he could generate, air resistance would be orders of magnitude weaker than the electro-magnetic losses.
In other words, it would stay spinning for literally hundreds of minutes if air resistance were the ONLY loss mechanism.
try using a round magnet, ball bearing type would be best. the square shape changes the magnetic fields and slow it down.
I might try it at some point but I dont see any reason that would make a huge difference.
Cody'sLab; It does increase the circularly induced eddy currents (kind of like a magnetic stirrer works). Asymmatry in the same plane as the conductor is bad news, but since you have a pretty substantial conductor in all 3 dimentions (and the entire vacuum chamber would also have a BIG effect, even though it is relatively far away - see Gauss' Law for charge screening), ANY deviation in the up-down direction would also cause quite a lot of enegy loss in those modes.
Cody'sLab laminating the metal to reduce eddy currents?
A round/disc magnet will have a axially symmetry magnetic field, if you rotate about the axis of symmetry the magnetic field doesn't change and so you can eliminate the eddy currents. To reduce the faraday disc effect you'd need to use only diamangetic levitation but i'm not sure of the relative strength of these effects. A square magnet doesn't have a axially symmetrical magnetic field.
Also you could just use polycardon which has a larger diamagnetic effect than bismuth but might be difficult to get a large enough sample.
MrEvilchickens the problem I see is finding a round magnet that is accurately symmetric enough. Without that, it will spin slanted (as the square magnet in the video) and have symmetry defects, which will end up with the same result (albeit maybe a slightly longer spin duration)
My hypotheses for why it stopped (in order of likelihood) are:
1) Eddy currents and magnetic resistance
3) Earth's magnetic field
2) Earth's gravity
4) Not a perfect vacuum
The solution: Use superconducting magnets in a perfect vacuum, in intergalactic space.
AFastidiousCuber it would already spin forever in space
Knuckles
Unless something gets in da wae
Has basicallybeen done, in the Gravity Probe B - Mission. Except they did it in an orbit around the earth, because gravity causes no friction, this difference does not matter. They levitated spheres coated in a superconductor cooled to 2K in a vacuum surrounded by superfluid helium, surrounded by a superconductor.
Basically, that’s planets and stars
The earth's magnetic field can be reduced by several magnitudes inside a Mu-Metal chamber
You just made a big bulky compass!
Wait...that makes so much sense. And even if he had a perfect magnet and a non conductive magnetic material, it would still stop because of the earth's magnetic poles.
No, it does not.
it's will just add some sinusoidal speed wooble, when rotation slowed down half way, and speed up other half.
Not sure if it is the earths magnetic field doing this or not. The question I have is why it unwinds when it stops, then rotates the opposite direction, and continues oscillating until it stops completely. Need to mark the spinning magnet and see if it stops every time in the same position relative the the earths magnetic field to be sure! Or it could be the orientation of the supporting magnetic fields. More testing needs to be done.
External magnetic field applies torque to the magnet, trying to align it's magnetic field. But there is no feedback according to magnet's spin speed, if magnet is not perfectly aligned it just always aplies some torque, until magnet crosses balance point at which torque changes direction. But magnet already got some momentum, it can't instantly stop. So it's continues to rotate after balance point until rotational force accumulates enough and it starts to spin other way.
I dont think it's only earth's mangetic field, huge magnet on top must add to it. Maybe, quite a lot. So it will be
resultant force.
Apart from the fact it's sitting inside a field made from a giant magnet sitting above it a million times stronger than the Earth's magnetic field.
Nothing lasts forever, even cold november rain....
sandqwert the correct answer is nothing, it will outlast anything, the problem nothing is the concept of the lack of anything, this concept could better be described but human intelligence can only go thus far, nothing was before the universe nothing will be after the universe, thus nothing lasts forever
the smell of farts under the duvet
it rains in november?
It's hard to hold a candle In the cold november rain.
But... Diamonds are forever... forevaah foreverahh
2:17 That's a really clever way of getting it spinning.
Not really clever, since it didn't work
Christopher Nah it didn't work, it wasn't strong enough as he said. I really like seeing how he sets stuff off with the laser though. I don't know what he could do without that thing.
I would have used water instead of wood, It would have boiled off in the vacuum and get the thing spinning i guess :)
water equalizes too much, you'd need to get ALL of the water your trying to heat up to boiling temperature which with a lazer would take ages
Matthew Bevan instead of burning wood, he can burn gunpowder, it would produce more gas.
Why not just hook up that little glass pipe to atmospheric pressure and have a 'vent' valve to push it? I think you could get better spinning with that.
I was thinking that while facepalming rly hard. Or yk he could've idk, remote-controlled a let?
Ugh..
the lazy nerd in me very much appreciates all the work you put into this channel! thanks cody!
A perpetual motion machine? In this house we obey the laws of thermodynamics!
chbrules I refuse to
@@vivimannequin REEEEEEEEE YOU CAN'T DON'T CREATE A PARADOX
Kono platelet da! Already got one planned
@@vivimannequin shit now I gotta go back in time before you plan that shit do you know how much ppl died because of you!
I understood that reference
you demonstrated why it won't spin forever, when you attempted to move the magnet to start it spinning. Although, there is no force of friction due to air, the bismuth's irregular shape experiences the magnetic field differently as it spins. this still acts as a type of drag. perhaps if you levitate a more perfect sphere you might see more noticeable effects.
Basically it wants to line up with the Earths magnetic field like a compass. I'm wondering what if you had a magnetic track and a superconductor that you pushed around the track, that will eliminate the magnetic flux, You would then have the issue of keeping the superconductor cold but if it was in a vacuum and levitating then it should stay cold.
From what?
Sounds like a pretty good second experiment
I'm so happy you did this because during my physics class in last year we were talking about efficiency of motors due to friction and it got me thinking about this exact situation, I just never had the opportunity to look into this.
I really LOVE these electro-magnetic experiments!
You could maybe try casting the bismuth into a circular mould with many thin pieces of plastic acting as insulators (like in transformer laminations).
Also, perhaps you could try a non conductive ceramic magnet (AlNiCo and Samarium Cobalt are about equally conductive, with ferrites being MUCH less conductive) as levitation device? You could theoretically even use many small pieces of Neodymium magnets (without the nickel coating of cource) and have them pin a thin insulator between themselves (mica perhaps?).
Hi-ed everyone, welcome back to Cody's Lab
i always assumed it was "alright everyone!" o.o
It is alright everyone...
Be easy on him, dude drinks cyanide and breathes Xenon.
For me it was " I know everyone" with a smiling face always.
Woah Bobby duke wtf are you doing here lmao, I’m subscribed tho😘
One of the most impressive things I see from you regularly is how you interact with things while they are in a vacuum chamber. Genius methods.
Interesting to see the experiment, love your creative ways of interacting with objects inside the vacuum chamber. +1 for Lenz's law.
I think the magnet probably slow down mainly because of Eddy currents.
Nice experiment though
I do think same way, but could you make that prediction before you seen magnet slowing down? I couldnt.
morpheus ꀊ Yes I agree!!
Eddy currents in bismuth are probably quite low, since it his high electrical resistance for a metal.
Copper Electrical resistivity is 16.78 nΩ·m (at 20 °C) or 0.00000001676 Ω·m
bismuth Electrical resistivity is 1.29 µΩ·m (at 20 °C) or 0.00000129 Ω·m
So if I did my math right bismuth has 76.8 times higher resistance then copper.
I'm thinking about making a bismuth tube to drop my 3/4" neodymium magnet through, so i can see how much the eddy currents slow it down compared to dropping it into a copper tube.
There is not much inertia going on in this magnet.
By the way, one comment out there pointed out, that if magnetic field would be very axial with center of mass, there would be no change of magnetic field in any point around magnet spinning on same axis.
So, +Cody'sLab, could you please check same with spheroidal or, may be, cylindrical magnet, and, may be, huge chunk of copper above it?
Cody, I think the magnet won’t spin forever because it will always point at magnetic north. Correct me if I’m wrong but that’s also why the magnet was favoring facing one side and than swinging back and forth as earths magnetic pull eventually brings it to a stop always facing the same direction.. go get a compass and see if I’m right Cody.
Visually stunning, informative, casual and clean editing; Cody, you gorgeous gangster - this is my favourite video of yours (been a fan since Westminster bees).
Great video as always. You never fail to inspire.
Bismuth is cool stuff.
electronicsNmore too bad he hasn't done a video centering around Bismuth
i'll risk making this comment before watching to the end of the video, but at 5:30 you can see there is some asymmetry in the magnetic field from the way the magnet seems to ever so slightly lurch into a "stable spot" before climbing back out again and continuing to rotate with slightly less speed.
Dn Fx That stable spot is the earth's magnetic field :^) - it's behaving like any compass and wants to align with the earth's field.
really ? seems like a good explanation, but i wouldnt have thought the effects of earth's magnetic field would contribute significantly enough to this system, given the much higher field strength of the magnets and bismuth Cody has set up here. Or is that still possible given that the forces from said magnets are mostly cancelled out ?
Basically it seems intuitive to me that this would spin a lot smoother and lose much less energy to this fabled stable spot, if the magnet was perfectly balanced and not sagging on one side. Or would it still get stuck on magnetic north in this "perfect" case ?
I think gravity as well as earth magnetic field is just adding sinusoidal wobble to speed. It does slow magnet down half way, but also do speed it up other half.
ah, yes. stopping caused by Foucault/Eddy currents in bismuth plate
posysajrazdwatrzy
No, the earth's field is at basically 90 degrees to the rotating magnet's field. It's pulling the magnet to flip on its side, not rotate on axis.
love the hints at the end
Great video, you actually got your answer as to whether or not it would spin forever at 3;00 you can see the magnet oscillating back and forth. Which means there's some kinda force on it.
try doing it with a sphere/ball magnet .
At the end, you're measuring the resistance increase in a coil when heated up by exposing it to the sun?
He could be pulling current out of a magnetic field with the coil, storing it, and then measuring it. Big loop o' wire under a power like will do the trick
Thank you so much for this video Cody. Back in highschool I wanted to research this for my "thesis" but my teacher thought I wouldn't be able to finish it. Now I finally know the outcome!
Thanks Cody, great video
the real secret to fidget spinning: vacuum chambers.
Cody when you put a microwave in your vacuum chamber it seemed to draw more power. If you put a microwave in a pressure chamber would it use less power ?
Gary Roe no, it's "working normally or arcing and consuming more power", so if pressure is not low, power consumption will be the same
Replace the air with a superfluid, maybe depending on your temperature. A fundamental experiment here, I love it! Analogues of this are still "spinning" with superconducting loops.
New vacuum chamber experiment vid! They're my favorites on your channel.
Since liquid oxygen is being attracted to a magnet and is not metallic, would it be possible to contain the oxygen in some form of container (like your glas tubes) to get rid of eddy currents and stuff? Or would you need a ridiculously huge magnet to lift the oxigen together wit its container?
Interesting
If I understand this correctly, if there is a little enough amount of radiation then items in a vacuum will just get colder and colder to a certain point (I may have misunderstood), so to that end if the oxygen is frozen and placed in a vacuum then it will stay cold enough to stay solid.
Alternatively you can always seal the container and if you keep it cold enough to not expand then you should be good.
Zeibentaul Unless the oxygen gave off a form of radiation, I don’t think it would decrease in temperature in the vacuum chamber. That said, it would expand into a gas, and the atoms might transfer their energy to the container walls (say, a sealed glass tube, not the walls of the vacuum chamber). So the gaseous oxygen may decrease in temperature relative to the increase in temperature of the container. Since all the energy would still be conserved within the system.
Zeibentaul
What about Earth's magnetic field??
Does it count?
chetan desai haha 😆 wait seriously 😳
Thank you for performing this experiment. I suggested it to another youtuber who plays with vacuum chambers but he totally butchered it in my eyes. This is pretty much exactly what I would have done, provided I had the stuff to try it.
from Kissimmee florida, love the videos cody keep up the great work
I'm wondering if there is a different factor here: Earth's magnetic field. That would explain a force that causes it to "rock" left and right at the end of the spin.
Hello Cody would the magnet spin better if it was balanced?
I beleive, it wont. Gravity might slow it down when one part of magnet is going up, but when it rotated 180 degree, same part will go down.
Great idea, had exactly that one in mind already years ago, but the perpetuum mobile will always be a dream that never comes true...
Perfect analysis! 👍
The magnetic field itself is resistance. You would need a constant permanent magnet inside the chamber to apply continuous pressure against it.
When I clicked on the thumbnail I expected to hear "Will it spin forever?" in the Blendtec guy's voice
The original video you did on this is why I started following you
I've been wanting to do this as well. Very good.
the earth's magnetinc feild could be messing with the motion of the little magnet.
i'm ignorant in the matter so don't laugh if i'm totally wrong XD
Field*
I'd say that it's possible, but I doubt that it's the only reason. Earth's Magnetic field surely interracts with it, but I also think there's more factors than just that.
Cody pls can you do More CODY'S MINE!
#CODY'SMINE
Super cool experiment 👍
Awesome video keep up the good work
Hi Cody, are you going to make another Q and A on reddit?
Well then you are two years late because when he had around 9000 subs he responded to me and almost every second comment :D
Adio_ I try clicking ur profile but I no get game
That would make a good fidget spinner
fidget spinner in a vacuum
great idea
In science we are learning about molecules and how they react with each other. I told my science teacher about your videos :D
The fact that the magnet is slowly oscillating back and forth when it should be at rest, indicates to me that it's not going to spin forever. There appears to be some resistance in the magnetic field itself that the object is "bouncing" off of. It will probably sit there and oscillate for a long time but eventually stop doing that as well.
Wouldn't a spherical magnet work better?
only ones up this late love u thow
its 2pm here
its 5 am here
3pm herre
Woke up an hour ago
It's CZcams.
You can literally just wait and watch it later.
That's the entire reason internet video replaced TV for people.
You could apply an electric field to the magnet above to get the magnet inside the chamber to spin. Eddy currents would slow the magnet eventually, however. It would spin longer than under atmospheric pressure.
When it started spinning in the opposite direction it was clear there are other forces applied.
Yes, gravity and the not perfectly vertical magnetic field the magnets make is what affects it
I want to see a fly in a vacuum.
Christie Nel A fly in a vacuum chamber is called a Walk. Also it'd probably die.
Funny!
Steven Cassidy actually it would not die, it just can’t fly in the chamber, the fly will survive. There is a video of a fly in a gas chamber. Search it up
That's already somewhere on youtube
Happy Chaps Gaming yeah but for how long. Animals need water and oxygen.
I have never drunk a glass of cyanide so fast before
Because of his pronunciation of "especially" and "theoretically"?
Who's your cyanide guy? Get that shit in powder form or not at all. At least inject if you have the misfortune of getting the liquid.
The magnet induces electricity in all the metal parts around it, which generates an electromagnetic field which counteracts the spin that created it. It's very much like the magnet in a copper tube experiment. Of course, with such a small magnet and such far away and not aligned metal parts the effect is nearly nonexistent, but it does waste some energy, which means that even if all forms of friction were removed the magnet will still eventually stop.
Also, generally acquiring perfect steady motion (including rotation) with anything that is magnetic is impossible because of the natural electromagnetic background of the Universe which will always slightly influence it.
EDIT: Oh, you've mentioned it. Well, leaving the comment for reference.
Great example of magnetic braking without any outside forces.
But will a fidget spinner in a vacuum spin forever???
cody piscitelli No
cody piscitelli Nope
You're asking the wrong questions. Will a fidget spinner still be cancerous if it's spinning in open space?
stani iliev you are cancerous
Thats how you get view boy
Haven't watched the video yet, but my answer is NO.
Well your profile pic is more cringe than your comment
Indie Bindie still less cringe then your asmr video... *shudders*
Sadly, your comment as useless as me not having yes/no answer before watching video. Second I seen it stopping, I instantly remembered Foucault currents. But i did not made that prediction before i watched.
Unless you wrote "why", you didnt really made good, strong prediction. And I didnt, which make's me sad.
morpheus ꀊ I applaud you for being honest and say that u didn't predict it before the video. I as well predicted no, but didn't have a why, neither was I able to have a reason for it.
morpheus ꀊ I know nothing about that current you're talking about. All I know is that perpetual motion are impossible- at the moment, no discoveries to prove it yet. And that's my basis.
Yup. I could watch this aaaaaaaalllll day!
There are a number of forces I can think of that may be causing the magnet to stop:
- Air flowing in slowly when the pump is turned off
- Vertical magnetic currents from the larger magnet, orthogonal to the rotation plane, causing alignment (like the moon has one face locked in position)
- The Earth's magnetic field, like in a compass
- Hysteresis currents
1 view
65 likes
logic is out the window
Why? If someone likes the video in the first few seconds, yt does not count it as a view, until you watch it till the end. Use your common sense before you talk.
+Bence Bujdosó Learn proper English before you talk.
What did you miss? Learn proper Hungarian before you try to make fun of my grammar mistakes.
Actually, the likes are updated instantly whereas the views are updated after a certain amount of time has passed. Say like every half an hour (As an example, I can't actually remember exactly how long).
VelvetCake people have been making this uninformed comment for over a decade
That it's rocking back and forth after the first attempt shows that it isn't just air resisting it spinning. Weight distribution or something else, there's a "hump" there that it has to overcome.
i think it will rotate much longer with a round magnetic form like a like a zylinder or a ball. Because the cube had a resistance to the magnetic field.
Get you an MKS SRG, The MKS Spinning Rotor Gauge (SRG) line is a high-vacuum gauge that operates by measuring the amount of viscous drag on a magnetically-levitated spinning ball, which is directly related to the number of molecules in the chamber (i.e. pressure).
I think you would need a perfectly ballanced cube or disk to let it turn longer, because the cube doesn't look's like that. If the cube is nearly at the end of the applied force, it swing's back and forth. Which means that there is a point on the cube lower than all other on the downside, which is affected by gravity.
Hi, Cody. You need to use a spherical magnet instead of a cube.
The magnetic field of a cube shaped magnet has components that vary with rotation angle. Rotation of the cube magnet then generates a time-varying magnetic field and this will always induce eddy currents in any metals near the magnet.
These eddy currents dissipate energy thermally. This is the energy loss that is damping the rotation of the cube magnet.
Since the field of a spherical magnet is unchanging with respect to rotation on its dipole axis, it eliminates the time-varying field components and thereby eliminates the eddy current losses that are damping the rotation of your cube magnet.
When using a spherical magnet, the only remaining source of eddy current induction will be due to imperfections in the magnets field due to material defects, but these will be very small effects.
it's pulling in one side, you can see it choosing a fixed position, going back and forward until it finds it. so the magnet is not positioned correctly, it's pulling in several directions at the same time
Hi Cody. I've been a fan for a little while.
it still react or lines up into the direction of magnetic poles of the earth like a compass that's why i think it will not really spin forever even if there is no air resistance.
The reason of the stop is lenz lawa, the magnet is inducing a current on the opposite direction hence creating a force to the other, this makes sense because if it where to go on forever you would be essentially making infinite energy
The Earth's magnetic field will also be absorbing energy from the system. Magnetic remanence is another source of loss. Then there's still a little bit of air still inside the chamber. Thanks Cody. Interesting,as always.
Funny to see such a science buff disappointed at not producing perpetual motion, but kudos to Cody for accepting evidence.
Before and during the experiment when it stopped it would then rotated a little in the opposite direction. I also noticed that the speed once it was in a vacuum varied depending on which side it was facing. That tells me that it isn't balanced. Even though it's being levitated it is still subject to the force of gravity. I think the heavy side is a force of friction.
Even if it did not work, this was a really cool experiment and a fantastic setup.
If I recall, the viscosity of air is constant down to about a torr, which is what you pumped down to, so you're probably still seeing significant air resistance effects. You might try with a lower vacuum pressure if your system can do that.
Ferrite cores used in high frequency switching transformers have magnetic properties but have low electrical conductivity, the core material is designed specifically to reduce eddy currents, not sure how well the material would work but it would be interesting to try.
If I remember correctly to limit eddy currents constructors of engines divide the magnet with several thin non conductor slices reducing a lot the area of the circles the current follow so limiting its effect substantially.
I may confusing it with some other dissipative effect though.
That little magnet is so cute.
People will find anything cute. Oh look at that cute bread crum! Lmao
pressurise that little bulb with the wood in it seal it with wax then melt the wax under vacuum.
The Coriolis effect will influence the spin of the magnet. also it doesn't look level.
and to a much smaller degree than the Coriolis effect light hitting the magnet will influence it. (Radiometer)
BUT they don't work by light bouncing off them as I once though it is actually heat and pressure. Which is why they spin towards the foil part and not towards the black.
Balance of the magnet will also effect it.
I have been wondering about this for decades, since like 5 minutes after I heard about the concept of perpetual motion machines.
Super cool! Tank you!
you know those hand crank flashlights? You feel more resistance the faster you crank them. That resistance is a rotating magnetic field cutting a conductor and inducing current into something. This is the force that stops this magnet
Apparently these magnets (assuming you're using a neodymium magnet) are usually coated with nickel having a 1.4*10^7 S/m conductivity but the neodymium iron boride, despite being a ceramic, has a conductivity of about 1*10^6 S/m. So, probably some of the effects of the eddy currents, which would indeed be on the surface of the magnet, would be somewhat lessened if you removed that coat.
Hey Cody I was about to dive into this. Check this out. Pipe an air compressor into the glass to push the magnet.
It has to be a very small amount of air pressure. And your decompresor would have to constantly run.
But just for proof of concept in space. This could be it.
My best guess is that this is caused by electromagnetic resistance. The best example i can think of when you crank a hand generator no matter how hard you push it ramps up slowly because of the resistance of the fields interacting with eachother.
Basically an electromagnetic form of friction
you should pressurize a fluid then bring it room temp. so that, when it depressurizes it will be about 40 F or "ice cold". in my ap chem class we thought of a soft drink that when you open it, it will depressurize and chill the drink inside so you don't have to chill your drinks.
The magnetic force between the magnets making the levitation makes it slow down like friction. Even if it didn't unless you had a complete vacuum air would slow it down eventually
The reason it slows down is eddy effect's, so it will generate a bit of voltage and slow down.
I think it is the magnet's "compass" behaviour that is slowing it down. As the magnet wants to point north it is periodically accelerating towards it and slowing away from it. Thats why when it is slowing down it will slow and then speed up before slowing again.
I imagine doing this experiment a considerable distance away from an active planet's core would work.
Eddy currents the changing magnetic field induce a current in the bismith. We need a non conductive paramagnetic material
powdered iron is used with a binder in RF inductors for exactly the reason you need: minimize eddy currents. It won't be zero but alot better than what you've got now. Also ferrites are used. Google powdered iron toroid or ferrite toroid for example.
ok. first off.. i loved hearing the bees 😂😂 but even though the magnet didn't spin for long, this was still an awesome experiment, and a great watch. the bees knees! 😊😊
You could try embedding a superconductor in solid nitrogen using evaporative cooling. The vacuum would freeze the nitrogen and would simultaneously isolate the whole thing so as long as you keep intense light from it, it would levitate.
Glass is diamagnetic. Not as much as Bismuth...but when the well the magnet floats within is self-centering, the last few spins remind me of torque translation, or putting square wheels on a vehicle over flat ground. At one face especially, it looks like it's climbing a hill, then falling down the opposite side. If I look really carefully, it appears that to be pistoning (up and down) against gravity; spinning in this well looks like work.
Forever is such a strong word...
Even in a perfect vacuum (and not just 1/800 of normal air pressure) it would still slow down. Even if you would remove everything you possibly could that interacts with the magnet it would slow down. Very, very slowly but it would still stop eventually.
There is always something that will interact with this system. If we assume that the universe will exist for all eternity in some fashion without ever stopping to exist and if we assume that this system can exist in this configuration for all eternity as well, even the tiniest possible influence on it will eventually make it stop spinning.
I guess it depends on how you define "forever" :) If you define it as "until no one exists anymore to witness it stop spinning" then I could get behind it. If no one exists anymore to care whether it's spinning anymore or not, I guess then we can say that it did spin forever ;)
Wood doesnt burn in vaccum, and probably there would be induction on the bismuth because it isn't a superconductor replicating identically the magnetic field lines. And the superior magnet would induce a current on the bottom one due to magnetic field flux be changing.
Thanks Cody, I aways wanted to see if it worked out, if I had condition I could do the same experimento that you did.