A metronome marks a steady pulse so performers can agree on how fast a piece moves.

The longer version

A mechanical or electronic clicker produces evenly spaced pulses, usually with a visual swing to match, so every player agrees on the rate before a note is sounded. Marking the rate is necessary because written symbols give relative lengths, not an absolute speed.

Markings describe tempo in beats per minute, and written terms for speed appeared long before the device did. Practising with a steady pulse exposes uneven timing, though performers often bend the rate deliberately for expression once the basic pulse is secure. Mechanical versions use an adjustable weight on a swinging rod; electronic ones count a clock. The same tune at a different rate can feel hurried or calm.

Where this entry sits

Sound and Music gathers facts about how vibrations move through air and water, how ears turn them into meaning, and how instruments and notation shape what listeners hear. Expect echoes, pitch, volume, acoustics, and the odd silence in between. The full list sits on the Sound and Music page, where every entry is listed in order.