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The experment would involve a small NIB magnet levitating between or on the diamagnetic material pyrolytic graphite, unlike other forms of levitation this doesn't require power to run such as electricity or that the levitating item be moving to maintain the effect. This does seem to require occasional adjustments, presumably as room changes temperature and two NIB magnets, one large and one small. The small magnet can levitate and rotate and tends to loose speed very gradually when set in motion, unlike a bearing that must make contact, or even some other magnetic levitations, the most significant force slowing the small magnet, at least at low speeds is air resistance.

The magnet could then be attached to the center of a necessarily very light object, for example a small disc, this is less straightforward than it sounds as cardboard tends to be too heavy and paper too flexible, I've found a thin, light, stiff plastic that works. Even smaller fins could then be attached to the edges of the disc at 90 degrees that are black on one side and white on the other, like a Crookes Radiometer.

At least the levitating part of this experement would be in a vacume and the rig would be made of non-magnetic materals to prevent attraction or eddy currents between the levitating magnet and the edge of the rig. A laser could then be directed at the edge of the disc to accelerate it to potentially vastly greater speeds than the more conventional blowing though a straw.

If this were constructed how quickly could the levitating material accelerate, pushed around by the laser.

For example how fast would be expected in RPM be given a 500mW laser, a typical vacuum for experiments and 10 hours?

edit: The tags won't let me choose magnetism or magnets, they keep changing to electromagnetism.

http://www.youtube.com/watch?v=lHugJfFbJoc

http://upload.wikimedia.org/wikipedia/commons/1/1d/Crookes_radiometer.jpg

http://1.bp.blogspot.com/_0pGYzSEhkxQ/TBUJZbewUUI/AAAAAAAAADg/e5mqQWk9_BQ/s1600/Floating_Magnet13.jpg

http://1.bp.blogspot.com/_0pGYzSEhkxQ/TBUJYZlEMfI/AAAAAAAAADQ/hVov2PRRtgo/s1600/Floating_Magnet11.jpg

http://4.bp.blogspot.com/_0pGYzSEhkxQ/TBUXZX-vXAI/AAAAAAAAAEU/xICBvsd24AA/s1600/floating_cuboid.jpg

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I don't think this will work because eddy currents in your rotating magnet (an electrical conductor) will probably damp its motion.Also, I don't think the laser can get it moving either.If you are basing the use of lasers to exert force a la Optical Tweezers, remember that those objects are very very small (micron size and transparent). Removed the down-vote. –  Antillar Maximus Dec 3 '11 at 3:42
    
Antillar Maximus, eddy currents in the rotating magnet don't seem to cause much slowing at least at low speeds, how does this resistance scale with speed? I have one of thease, it looks just like this one upload.wikimedia.org/wikipedia/commons/1/1d/Crookes_radiometer.jpg Sunlight is enough to cause this to turn, the resistance to movement is greatly higher with this as there is physical contact so I think a system like this but with much less loss and a more powerfull push would work. –  alan2here Dec 3 '11 at 16:20
    
Nice idea alan2here! I first thought that it should not work (Earnshaw's theorem), but this does not apply for diamagnets. For your question: You will still have eddy currents in the graphite that will slow it down a bit. The maximum speed can be quite high, I guess that depends mostly on the magnet. If it is not completely balanced it will wiggle around and probably touch the graphite. –  Alexander Dec 3 '11 at 17:53
    
Pushing the magnet sideways more than a little causes it to fall out of the levitation but pushing it a little dosn't matter as it returns to the center itself seemingly at any speed, same with tilt. If imperceptible eddy currents are caused by the moving magnet agaisn't the static graphite then perhaps the graphite should be cylindrical with very thin pie chart\cake slice shaped wedge removed to prevent this. Except that could then cause the magnet to slide away where the narrow gap is, but perhaps that sort of thing. tyvm for the up votes. Can anyone here do the maths? –  alan2here Dec 4 '11 at 16:33

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