The instrument that produces sound by striking strings with hammers is the piano.
When a pianist presses a key, the piano’s action propels a small felt-covered hammer toward one or more tightly stretched strings. The hammer rebounds immediately after striking, allowing the string to vibrate. That vibration travels through a bridge to the soundboard, which helps project and amplify the sound. Dampers stop the strings when the key is released, unless the sustain pedal keeps them ringing.
The piano was developed from earlier keyboard and struck-string instruments. Its invention is generally credited to Bartolomeo Cristofori, an instrument maker in Florence who created an early version around 1700. Cristofori’s design made it possible to vary loudness through touch, unlike the harpsichord, whose strings are plucked and whose individual notes have much less dynamic control.
A modern piano typically has 88 keys, though some instruments differ. The two principal physical forms are the grand piano and the upright piano. The clavichord is a frequent distractor: it also uses struck strings, but metal tangents remain in contact with them, producing a much quieter sound.