Hammer, anvil and stirrup
Hertz

Hammer, anvil and stirrup
These three bones which are also called the ossicles are the tiniest bones in the human body.
When sound waves make the eardrum vibrate these vibrations are continued by the movement of the ossicles. The innermost of the ossicles (the stirrup) moves and creates motion in the fluid of the cochlea.

Hertz
Hertz is the unit measurement of frequency (pitch) of sound. The number of cycles of a sound wave in one second (cycles per second) is more commonly specified in hertz (Hz). High-pitched sounds, such as a police whistle, have a high frequency with thousands of cycles per second. Low-pitched sounds, such as far away thunder, have a low frequency with only a few cycles per second.