What is a Gyroscope?

T. Levi

The gyroscope was named by Leon Foucault, a French physicist, in an 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.

Gyroscopes are used in guidance systems from some missiles.
Gyroscopes are used in guidance systems from some missiles.

Usually, in modern gyroscopes, the rotor is constantly spinning. Constant spinning adds 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 does not change its orientation. The spinning of the rotor means that any change in orientation affects all points on the rotor equally, causing the rotor to spin on a fixed axis. This is called precession.

Gyroscopes are used in some aircraft compasses.
Gyroscopes are used in some aircraft compasses.

Precession creates a fixed orientation. The rotor spins on a fixed axis while the structure around it rotates or tilts. In space, where the four compass points are meaningless, the axis of the spinning rotor is used as a reference point for navigation.

In addition to the rotor, modern gyroscopes typically have two additional rings, called gimbals, in the center of a larger stable ring. The rotor spins on an axle connected to the smaller, inner gimbal. This gimbal rotates on a horizontal axis created by its connection to the larger, outer gimbal. The larger gimbal rotates vertically and spins on an axis connected to the stable outside ring.

Gyroscopes are in compasses for airplanes, spacecraft, and boats. In airplanes, the pitch and orientation of the airplane is measured against the steady spin of the gyroscope. In space, where there are few reference points to help navigate, the spinning center of the gyroscope is used as a point of orientation.

Massive gyroscopes are used to stabilize large boats and some satellites. They are also used in guidance systems in some missiles. They even make a fun children's toy.

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Discussion Comments


@hidingplace - Because of the mass and rotation of a gyroscope it creates a dynamic property that is known as angular momentum. The laws of dynamic properties suggests that angular momentum is conserved, so the axis of rotation tends to stay pointing in the same direction. The resulting effect of a gyroscope attached to any body is that it stabilizes the body's motion, so it can reduce the rocking of a ship or it can be used as a control system in aircraft, torpedoes, etc. It's fascinating stuff.


How exactly do gyroscopes work to stabilize large boats and satellites?

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