Can you feel sound waves with your hand at this very moment? Probably you can't. But suppose you hold a balloon. Then your hand can feel sounds because the balloon membrane vibrates. Just like the balloon, your ear has a membrane that vibrates when sound waves strike it.
Your ear is a complex system that consists of three main regions—the outer ear, the middle ear, and the inner ear—as shown in Figure 19. The outer ear gathers and focuses sound into the middle ear, which receives and amplifies the vibrations. The inner ear uses nerve endings to sense vibrations and send signals to the brain.