How Does a Gyroscope Work?

A gyroscope is a spinning wheel or disc mounted in gimbals (pivoted supports that allow free rotation). When spinning rapidly, the gyroscope exhibits two key properties: rigidity in space (the spin axis maintains its orientation regardless of how the frame moves, due to conservation of angular momentum) and precession (when a torque is applied, the gyroscope axis rotates perpendicular to the applied force, rather than in the direction of the force). These counterintuitive behaviours are governed by the angular momentum vector L = I * omega (moment of inertia times angular velocity). The higher the spin rate, the greater the angular momentum, and the more strongly the gyroscope resists reorientation. Gyroscopes are used in: aircraft attitude indicators (artificial horizons), ship stabilisers, smartphone orientation sensors (MEMS gyroscopes), the Hubble Space Telescope pointing system, missile guidance (inertial navigation), and bicycle stability (the gyroscopic effect of spinning wheels helps keep a bicycle upright, though recent research shows it is not the primary factor).