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How does a human hear? When an object makes a noise, it sends vibrations (better

known as sound waves) speeding through the air. These vibrations are then funneled into

your ear canal by your outer ear. As the vibrations move into your middle ear, they hit

your eardrum and cause it to vibrate as well. This sets off a chain reaction of vibrations.

Your eardrum, which is smaller and thinner than the nail on your pinky finger, vibrates

the three smallest bones in your body: first, the hammer, then the anvil, and finally, the

stirrup. The stirrup passes the vibrations into a coiled tube in the inner ear called the

cochlea. The fluid-filled cochlea contains thousands of hair-like nerve endings called

cilia. When the stirrup causes the fluid in the cochlea to vibrate, the cilia move. The cilia

change the vibrations into messages that are sent to the brain via the auditory nerve. The

auditory nerve carries messages from 25,000 receptors in your ear to your brain. Your

brain then makes sense of the messages and tells you what sounds you are hearing.

While you are sitting in the meadow, you might hear a calm breeze,some bees

buzzing around and maybe some birds chirping. The wind rustles through grass and

creates sound waves. Your ears collect these sound waves and causes your eardrum to

also vibrate. The eardrum the makes your hammer, anvil, and stirrup. The stirrups

vibrations move the liquid in your inner ear and the cilia translate those vibrations into

something the brain can understand. The brain processes the messages and realizes that

you are hearing a calm breeze. The same thing would happen if you heard a bee buzzing

around, except the different sound waves that it makes would cause the ear to process a...