My ears
People talk to me. Car horns honk. Dogs bark. Music is somewhere nearby.
I know about these sounds because my ears and my brain work together.
My ears turn sounds into nerve messages. Nerves in my ears carry the
messages to my brain. And my brain understands them. This is how that
happens.
Sounds are air waves. The air waves enter my ear and bump against my
eardrum. My eardrum moves when airwaves hit it.
When my eardrum moves, it bumps into three small bones called the
hammer, the anvil, and the stirrup. As these bones bump against each
other, the stirrup moves in and out of an opening in a place that looks
like a snail shell. This place is called the cochlea. Inside the cochlea
are liquid and nerves. As the stirrup moves in and out of the opening of
the cochlea, it makes waves in the liquid. The waves move across the
nerves.
When that happens, the nerves carry messages to my brain. My brain tells
me there’s a sound. And it tells me what kind of sound I hear.
So, if somebody speaks to me, I know it. If a horn honks, I know it. And
if a dog barks, I know that, too. I hear!
The parts of my ear
I can touch only part of my ear. Most of my ear is inside my head. Some
parts of my ear don’t show on this picture. These parts help me to keep
my balance. You can read about them on pages 84 and 85.
