Sound waves are collected by the outer ear and channeled along the ear canal to the eardrum. The impact of sound hitting the eardrum creates vibrations that cause three bones in the middle ear -- the malleus, incus, and stapes (hammer, anvil and stirrup) -- to move. The smallest, the stapes, fits into the oval window between the middle and inner ear. When the oval window vibrates, fluid in the inner ear transmits the vibrations into the hearing organ, called the cochlea.

In the inner ear, thousands of microscopic hair cells are bent by the wavelike action of fluid inside the cochlea. The bending of these hairs sets off nerve impulses that are then passed through the auditory nerve to the hearing center of the brain. This center translates the impulses into sounds the brain can recognize.

Did you know?

* Your ears aren't just good for helping you hear. They help you keep your balance as well. Near the top of the cochlea are three loops called the semi-circular canals. These canals are full of fluid that moves when you move your head. It pushes up against the cilia and sends messages to your brain that tells it how your body is moving.

You know that feeling of dizziness after you have been spinning around? Well, the fluid in you ears spun as well. That makes the cilia move in all different directions and confused your brain.

* Children have more sensitive ears than adults. They can hear a larger variety of sounds.

* Dolphins have the best sense of hearing amongst all the animals. They are able to hear 14 times better than humans.

* Too much fluid putting pressure on your eardrums causes earaches. They are often a result of infection, allergies, or a virus.