Abstract. Diamagnetic objects are repelled by magnetic fields. If the fields are strong enough, this repulsion can balance gravity, and objects levitated in this way can be held in stable equilibrium, apparently violating Earnshaw’s
theorem. In fact Earnshaw’s theorem does not apply to induced magnetism, and it is possible for the total energy(gravitational + magnetic) to possess a minimum. General stability conditions are derived, and it is shown that stable zones always exist on the axis of a field with rotational symmetry, and include the inflection point of the magnitude of the field. For the field inside a solenoid, the zone is calculated in detail; if the solenoid is long, the zone is centred on the top end, and its vertical extent is about half the radius of the solenoid. The theory explains recent experiments by Geim et al, in which a variety of objects (one of which was a living frog) was levitated in a field of about 16 T. Similar ideas explain the stability of a spinning magnet (LevitronTM) above a magnetized base plate. Stable levitation of paramagnets is impossible.
Reddfugee42@lemmy.world
on 02 Dec 18:41
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The only way a frog can levitate by itself is after it builds a complicated multimillion dollar machine and gets inside. But granted, at that point, it becomes a very impressive frog.
TheFogan@programming.dev
on 02 Dec 18:44
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I mean, yeah, that’s pretty well known, but frogs are definitely not
Gustephan@lemmy.world
on 03 Dec 16:18
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I had to be at the mag lab in Tallahassee semi regularly during my undergrad, where they would demonstrate the magnetic levitation of a frog from time to time. The place had systems with cryo pressure high enough to turn an improperly sealed hatch into a very deadly projectile for anybody unlucky enough to be in the same room
surrealpartisan@lemmy.world
on 05 Dec 12:56
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Andre Geim got the Ig Nobel for this. He is the only person this far to have got both the Ig Nobel and an actual Nobel prize.
threaded - newest
Paper
I’ma gonna save y’all from downloading a pdf.
The only way a frog can levitate by itself is after it builds a complicated multimillion dollar machine and gets inside. But granted, at that point, it becomes a very impressive frog.
www.youtube.com/watch?v=KlJsVqc0ywM
TIL frogs are diamagnetic
Water is also diamagnetic
I mean, yeah, that’s pretty well known, but frogs are definitely not
I had to be at the mag lab in Tallahassee semi regularly during my undergrad, where they would demonstrate the magnetic levitation of a frog from time to time. The place had systems with cryo pressure high enough to turn an improperly sealed hatch into a very deadly projectile for anybody unlucky enough to be in the same room
Andre Geim got the Ig Nobel for this. He is the only person this far to have got both the Ig Nobel and an actual Nobel prize.