Rocket finds a curly snail shell on the path. "This looks like a tiny spiral staircase," he says.
Raven turns it over. "What do you notice about its shape?"
Nova hovers above the shell. "Something deep in your ear has that same shape," she says. "Can you find its name?"
Deep in the inner ear is the cochlea (say: KOH-klee-uh).
It is shaped like a snail shell, and it is filled with fluid.
The tiny bones pass vibrations into the cochlea. The fluid inside ripples.
Tiny sensory cells called hair cells ride the ripple, like surfers on a wave.
When the hair cells move, they make a nerve signal.
Different hair cells notice different sounds.
Hair cells near the wide end of the cochlea notice high sounds.
Hair cells closer to the center notice low sounds.
The auditory nerve carries the signals from the cochlea to the brain.
The brain turns the signals into sounds you know and understand.
A part of the brain near your ears helps you understand sounds and words.
| Statement | True or false? |
|---|---|
| Hair cells in the cochlea make nerve signals. | ? |
| The auditory nerve carries signals to the brain. | ? |
| The ear understands words without the brain. | ? |
Excellent listening! Tomorrow we find out how the inner ear also keeps you from tipping over.