How do pianos work?

Answer 1

Grand pianos and acoustic uprights are different.

Grand piano: A key is a long piece of wood which is balanced on a rail in the middle of the keybed. Depressing the key makes the opposite end lift up, putting to work an extremely complex series of mechanisms constructed of wood, hyde glue, felt, leather, springs, and small metal pins. A small piece of wood called a jack pushes against a felt and leather roll called a knuckle or a roller, which is glued on the backside of the hammer shank near the pivot-axis, making the hammer move or shoot upwards; the hammer is a rolled, compressed, and cut piece of felt attached on a shank which hits 3 (2 and 1 in the bass section) metal strings from under to produce a sound. A felt damper moves off of the string as the key is depressed to let the strings vibrate, and as the key is allowed to return to normal, the damper comes back down on the string, stopping vibrations and therefore discontinuing the production of sound. The design of the action, which needs to be finely tuned, allows for all of the pieces to naturally fall back into their original start-up positions. A damper pedal for the feet results in all dampers to be removed from the strings, allowing harmonics on other notes in common with the note you are playing to be excited and start vibrating on their own, making the sound dynamic as different parts of the sound are coming from different parts of the piano. There is far more to know about the action, such as repetition and the roles of each piece, as well as pieces elsewhere on the piano which have a purpose on their own, though that is enough information to fill a book.

Answer 2

when you press the keys they make the hammers inside the piano hit the strings inside the piano; making vibrations which create sound.