Levitation
From Wikipedia, the free encyclopedia
Levitation (from Latin levo, to raise) is the process by which an object is suspended against gravity, in a stable position, by a force without physical contact.
It is also a popular conjuring trick, such as apparently raising a human being without any physical aid. The illusion can be produced by clever mechanics, lighting arrangements or other means.
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[edit] Physics
On earth all that is required for levitation is a force vertically upwards equal to the object's weight. This can be achieved through many different means, for example magnetic, electrostatic (i.e. electrically charged objects) or aerodynamic forces. By means of magnetic levitation even small live animals have been forced to levitate.
Aerodynamic levitation is commonly seen in air hockey where jets of gas from the table push upwards against the puck. Levitating objects may also force air downwards e.g. Helicopters, VTOL aircraft, and hovercraft. A sphere can be stably levitated in a stream of air without any type of control system, if conditions are right. These effects are due to Bernoulli's principle. This was merchandised as a toy, circa 1960.
[edit] Paranormal and religious beliefs
The concept of levitation is also a part of some Eastern religions and magical beliefs.
Some beliefs include ideas that there are paranormal ways to levitate objects. These may include mystical or magic-related methods of raising an object off the ground. Perhaps the most famous example is of monks and/or religious people that live a hermetic life levitating at will, a common element in hagiography.[citation needed] Despite numerous anecdotes there exists no evidece supporting such claims.
"Levitation" is also used in reference to an apparent levitation.
In science fiction and fantasy, some fictional characters possess the power to lift themselves above the ground via levitation. Example: Phoebe Halliwell in Charmed.
[edit] History
The original use of the word was to refer to such inexplicable claims, as in wonder stories and unauthenticated reports; the use of the word to describe an actual, physical means of "making things float in the air" is a recent development.
[edit] See also
- Acoustic levitation
- Magnetic levitation
- Magical levitation techniques
- Metaphysical levitation
- Antigravity
[edit] Further reading
- Schiller, Christoph (2007). Motion Mountain: The Free Physics Textbook. esp. the section on levitation in the chapter on electromagnetism.
