Magnetic Levitation is a way to suspend objects in air without any support, as if in defiance of gravity. An unsung phenomenon of the past which is now being put to use in a variety of interesting and useful applications. As a child we must have seen a ping pong ball being levitated on an air stream at the output pipe of a vacuum cleaner. Magnetic levitation, also known as maglev is used in a similar way to levitate objects in air without any support, using magnetic field.
Levitation is the process by which an object is suspended against gravity, in a stable position, without physical contact. 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, magnetic levitation is the most common.
Though any electromagnetic force could be used to counteract gravity, magnetic levitation is the most common. Diamagnetic materials are commonly used for demonstration purposes. 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.
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