Scotch tape and flying frogs

This year’s Nobel prize in physics went to Andre Geim and Konstantin Novoselov for making single layer graphite or graphene using scotch tape.  However, Geim is also famous for having won an Ignoble prize for demonstrating diamagnetic levitation using a frog.  You can see a video of a flying frog and tomato hereSir Michael Berry of Berry’s phase fame and Geim wrote a paper demonstrating that diamagnetic but not paramagnetic objects can be levitated stably in a solenoidal magnetic field.  This was somewhat surprising because there is a theorem (Earnshaw’s theorem) that says you cannot suspend an object with fixed charges and magnets in any combination of static, magnetic, and gravitational fields.  The reason diamagnetic levitation works is because Earnshaw’s theorem does not apply to induced magnetism.


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