Levitation of matter is possible using developed methods that include acoustic, aerodynamic, magnetic, electromagnetic, gas film, electrostatic and optical levitation techniques. Levitation is the action in which an object is suspended in a stable spot with no physical contact.
Using powerful electromagnets utilizing superconductors, scientists have levitated mice, grasshoppers and frogs. Maglev trains use magnetic levitation to hover above the tracks, permitting them to reach high speeds due to the elimination of friction. Acoustic levitation uses sound to counteract the force of gravity by using nonlinear ultrasonic waves to cause a response in the mass it is traveling through. Acoustic levitation is used in the study of corrosive materials, manufacturing and in the study of foam physics. Aerodynamic levitation employs a stream of gas to suspend an object in the air. A hovercraft is an example of an machine using aerodynamic levitation.