A Y-shaped metal implement, usually made from steel, that vibrates or rings at a specific pitch when struck. The resulting pitch is used as a reference for tuning musical instruments.
British trumpeter John Shore invented the tuning fork in 1711. The shape of the tuning fork was designed to emphasize the fundamental, while de-emphasizing any overtones. The handle, or base of the “Y,” can be placed on a resonant surface to increase the volume of the tuning fork.
Most tuning forks are tuned to A = 440Hz (concert pitch), though different reference pitches were and are available. The tuning can be changed by filing metal off of the “arms” or tines. Where the metal is removed determines whether the pitch produced is raised or lowered.
Trivia: The tines of a Rhodes electric piano are similar to tuning forks. Tuning forks have been used in watches, for hearing tests and nervous system evaluations, for radar gun calibration, and in gyroscopes.
More trivia: There is a node or vibrational null where the two tines of the fork meet.
Even more trivia: The sound waves produced by the tines are 180 degrees out of phase. Placing a sheet of sound-blocking material between the tines of a tuning fork can increase its volume.