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Levitation
From Wikipedia, the free encyclopedia
This article is about the scientific techniques of levitation. For the magic illusion, see Magic (illusion). For paranormal activity, see Levitation (paranormal). For other uses, see Levitation (disambiguation).
A cubical magnet levitating over a superconducting material (this is known as the Meissner effect)
Levitation (from Latin levitas "lightness")[1] is the process by which an object is suspended by a physical force against gravity, in a stable position without solid physical contact. A number of different techniques have been developed to levitate matter, including the aerodynamic, magnetic, acoustic, electromagnetic, electrostatic, gas film, and optical levitation methods.
Contents[hide] * 1 Physics * 2 Levitation methods * 2.1 Magnetic * 2.2 Electromagnetic * 2.3 Electrostatic * 2.4 Aerodynamic * 2.5 Acoustic * 2.6 Gas film * 2.7 Optical * 2.8 Casimir Force * 2.9 Buoyant levitation * 3 Uses * 3.1 Animal levitation * 3.2 Maglev trains * 4 Further reading * 5 See also * 6 References * 7 External links |
[edit] Physics
For levitation on Earth, first, a force is required directed vertically upwards and equal to the gravitational force, second, for any small displacement of the levitating object, a returning force should appear to stabilize it. The stable levitation can be naturally achieved by, for example, magnetic or aerodynamic forces.
Levitation techniques are useful tools in physics research. For example, levitation methods are useful for high-temperature melt property studies because they eliminate the problem of reaction with containers and allow deep undercooling of melts. The containerless conditions may be obtained by opposing gravity with a levitation force, or by allowing an entire experiment to freefall.[2]
[edit] Levitation methods
A number of different techniques have been developed and are commonly used to produce...