In the piano family, the piano produces sound when felt-covered hammers strike strings.
Pressing a piano key activates a mechanism that throws a hammer toward one or more strings. The hammer then rebounds, allowing the strings to vibrate freely while a damper controls their sound when the key is released. The player can vary loudness by changing the speed of the hammer, which gives the piano its distinctive dynamic range.
Bartolomeo Cristofori developed the instrument in Italy around 1700. His early name, gravicèmbalo col piano e forte, described a keyboard instrument capable of both soft and loud sounds. The shorter name “piano” eventually became standard. Modern grand and upright pianos retain the same basic hammer-action principle, although their frames, actions, pedals, and string layouts differ.
A harpsichord plucks its strings rather than striking them, so its volume is not controlled in the same direct way. A celesta uses hammers to strike metal plates, and an organ produces sound through pipes or electronic systems instead of stretched piano strings.