What is a gyroscope ?

A gyroscope is any rotating body that exhibits two fundamental properties: gyroscopic inertia or rigidity in space and precession or the tilting of the axis at right angles to any force tending to alter the plane of ratation. These properties are inherent in all rotating bodies, including the Earth itself. The term gyroscope is commonly applied to spherical, wheel-shaped or disk-shaped bodies universally mounted to be free to rotate in any direction. They are used to demonstrate these properties or to indicate movements in space. A gyroscope constrained from moving around one axis other than the axis of rotation is sometimes called a gyrostat.