The Physics Of Pianos

Pressing a piano key causes a hammer to hit a taut string. Struck taut strings vibrate, and, vibrating strings produce sound waves. The first piano key on the left side of a properly tuned piano creates a sound wave with a frequency of 27.5 Hz. Moving one key to the right always increases the corresponding sound wave frequency by a factor of 2^1/12. Notice that moving by 12 keys doubles the frequency. Also notice that because a piano has 88 keys that the highest sound wave frequency is 4186.01 Hz.