How Does a Piano Make Sound?

Each key operates a lever system called the action, which throws a hammer against one, two or three strings and lets it bounce straight off. The string's pitch depends on its length, tension and thickness, with long heavy strings for bass notes and short thin ones for treble. A standard modern piano has 88 keys and around 230 strings. The vibrating strings pass energy through a bridge to the soundboard, which moves more air and makes the sound loud enough to fill a room. Dampers stop the strings when you release a key, unless the sustain pedal holds them off.