|When you look at the side of a person's head you see the outer ear. The outer ear is made of cartilage. Nature has cleverly designed the outer ear to catch and direct sound waves through an opening into the ear canal.
The vibrations travel through the air inside the ear canal to the eardrum. Like a drum, the eardrum is made of thin tissue stretched tightly across an opening. Each of your eardrums is only about as big as the fingernail on your little finger. Sound waves enter the ear and make the eardrum vibrate. Those vibrations travel through three bones deep inside the ear. They are called the malleus (or hammer), incus (or anvil), and stapes (or stirrup). These are the tiniest bones in the body. They get their names from their shapes. The hammer looks like a tiny hammer. The anvil looks like an anvil, the heavy iron surface that a blacksmith uses. And the stirrup is shaped like a stirrup, the metal ring for a horse back riderís foot.
Vibrations are passed from the hammer to the anvil to the stirrup, and then on to the cochlea. The cochlea is spiral shaped. The cochlea is filled with liquid, which vibrates as sound enters. When the liquid vibrates, it shakes tiny hairs inside the cochlea. The hairs are connected to nerves that send signals to a big nerve called the auditory nerve. The auditory nerve carries the signals to the brain and, you hear the sound.
Directions: Answer the following questions.