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demonstrations:5_electricity_and_magnetism:5h_magnetic_fields_and_forces:levitron:start [2019/04/26 23:18] demoroom |
demonstrations:5_electricity_and_magnetism:5h_magnetic_fields_and_forces:levitron:start [2020/01/22 22:38] demoroom [Purpose] |
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===== Purpose ===== | ===== Purpose ===== | ||
- | [[wp>earnshaws_theorem|Earnshaw's Theorem]] (essentially) says that it's not possible to make any stable arrangement of magnets such that they are held in equilibrium by only their electromagnetic interactions. This means that it is not possible to levitate magnets with only magnets. With a stabilizing element such as the rotation of the top, however, it's possible to levitate for a time. | + | [[wp>earnshaw's_theorem|Earnshaw's Theorem]] (essentially) says that it's not possible to make any stable arrangement of magnets such that they are held in equilibrium by only their electromagnetic interactions. This means that it is not possible to levitate magnets with only magnets. With a stabilizing element such as the rotation of the top, however, it's possible to levitate for a time. |
===== Apparatus ===== | ===== Apparatus ===== | ||
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The manual has a very helpful flowchart but here are the key helpful points: - If the top doesn't lift itself, reduce the mass. - If the top lifts off but flies away, raise the leg closest to where it flew off. Adding mass might also help. | The manual has a very helpful flowchart but here are the key helpful points: - If the top doesn't lift itself, reduce the mass. - If the top lifts off but flies away, raise the leg closest to where it flew off. Adding mass might also help. | ||
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+ | [[http://math.ucr.edu/home/baez/physics/General/Levitation/levitation.html|This page]] has some interesting information regarding how Earnshaw's theorem relates to the problem of magnetic levitation, and what can be used to circumvent the limitation (by of course, violating the theorems assumptions). | ||
<WRAP group> | <WRAP group> |