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A cubical magnet levitating over a superconducting material (this is known as the Meissner effect)
Magnet levitating above a superconductor cooled by liquid nitrogen
Diamagnetic levitation of a live frog.

Levitation (from Latin levitas "lightness")[1] is the process by which an object is suspended against gravity, in a stable position, without physical contact.

It is also a conjuring trick, apparently raising a human being (or other object) without any physical aid. The illusion can be produced by clever mechanics, lighting arrangements and other means.

Contents

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.

Though any electromagnetic force could be used to counteract gravity, diamagnetic materials are most commonly used. In this case the returning force appears from the interaction with the screening currents. For example, a superconducting sample, which can be considered either as a perfect diamagnet or an ideally hard superconductor, easily levitates an ambient external magnetic field. In very strong magnetic field, by means of diamagnetic levitation even small live animals have been levitated.

By means of aerodynamic forces, the effect of levitation can also be achieved using the upthrust of air, with the levitating object having the same average density as air.

Acoustic levitation uses sound waves to provide a levitating force.

Scientists have discovered a way of levitating ultra small objects by manipulating the so-called Casimir force, which normally causes objects to stick together due to forces predicted by quantum field theory. This is, however, only possible for micro-objects.[2][3]

Animal levitation

Scientists have levitated frogs, grasshoppers, and mice. The mice acted confused at first, but adjusted to the levitation after about four hours.[4]

Further reading

References

  1. ^ Levitate, "to rise by virtue of lightness," from Latin levitas "lightness," patterned in English on gravitate: Online Etymology Dictionary
  2. ^ Scientists reveal secret of levitation, Yahoo! News
  3. ^ Levitation in Miniature, Null Hypothesis
  4. ^ NASA Levitates a Mouse With Magnetic Fields, Popular Science, September 9, 2009

See also


Wiktionary

Up to date as of January 14, 2010
(Redirected to levitation article)

Definition from Wiktionary, a free dictionary

See also lévitation

Contents

English

Etymology

From the verb to levitate (from Latin levitas "lightness," patterned in English on gravitate) + -ation.

Pronunciation

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Noun

Singular
levitation

Plural
levitations

levitation (plural levitations)

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  1. The raising of something, such as a body, without apparent physical cause, allegedly using the power of the mind
  2. The suspension of something via technical means without any mechanical support, such as by magnetism

Translations

The translations below need to be checked and inserted above into the appropriate translation tables, removing any numbers. Numbers do not necessarily match those in definitions. See instructions at Help:How to check translations.

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Anagrams


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