What is a “gyroscope”?
gy-ro-scope ^–re-,sko^-p, Brit n [F] (1856) :a wheel or disk mounted to spin rapidly about an axis and also free to rotate about one or both of two axes perpendicular to each other and to the axis of spin so that a rotation of one of the two mutually perpendicular axes results from application of torque to the other when the wheel is spinning and so that the entire apparatus offers considerable opposition depending on the angular momentum to any torque that would change the direction of the axis of spin.
The gyroscope was invented by Leon Foucault, a French physicist, in the attempt to demonstrate the earth’s rotation. A freely rotating disk, called a rotor, was mounted on a spinning axis in the center of a larger, stable wheel. As the earth spun on its axis, the stable wheel rotated with it, but the rotor did not move. The movement of the mounted wheel followed the rotation of the earth, rotating around the center disk and demonstrating the earth’s spin. Usually, in modern gyroscopes, the rotor is constantly spinning. Constant spinning ads certain properties to the gyroscope and increases its uses. Just like a spinning top, which remains level on a tilted surface, the spinning center of a gyroscope never changes its orientation. Because the rotor is spinning, any change in orientation affects all points on the rotor equally, causing the rotor to spin on a fixed axis. This is called precession. Precession creates a fixed orientation. The rotor spins on a fixed axis while the structure
(The following definition of a gyroscope is simplified) Usually gyroscopes take the form of a disc shaped object but can be any object that produces an effective gyroscopic behavior. Most of the gyroscopes mass should be as far away from the center as possible. This often results in a disc with a large heavy rim. When the gyroscope isn’t rotating it behaves like any other object, however when the gyroscope is spun on its axis at high speed it resists movements in certain directions.
