Vibration turned into signals
How Do You Hear?
Sound shakes your eardrum, tiny bones amplify it, and hair cells convert it to nerve signals.
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Step 1 of 5
Sound is moving air pressure.
A vibrating object squeezes and stretches the air around it, and that pattern travels outward. Hearing is detecting those pressure changes.
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Step 2 of 5
The eardrum vibrates in step.
A thin membrane, tightly stretched, moves in and out exactly matching the arriving pressure. It copies the sound faithfully as motion.
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Step 3 of 5
Three tiny bones amplify it.
The smallest bones in your body lever the eardrum's movement into a much stronger push. Without them, most sound would reflect off the inner ear fluid.
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Step 4 of 5
A coiled tube sorts out the pitch.
The cochlea is a fluid-filled spiral. High notes shake the near end, low notes the far end — so position along it means pitch.
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Step 5 of 5
Hair cells make the nerve signals.
You are issued one set of these. Loud noise spends them permanently. Thousands of microscopic hairs bend as the fluid moves and fire nerve impulses. Once damaged by loud noise, they never grow back.
Two ears let you locate sound: a noise from your left arrives a fraction of a millisecond sooner on that side.
The short version
Hearing turns air pressure into eardrum motion, amplifies it with tiny bones, and sorts it by pitch along the cochlea.
Try it yourself
Hum with fingers in your ears. You hear it through bone instead of air — the same hair cells, a different route in.