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Vibration turned into signals

How Do You Hear?

Sound shakes your eardrum, tiny bones amplify it, and hair cells convert it to nerve signals.

1 Air vibrationsarrive2 The eardrumshakes3 Hair cells fire— you hear it
A chain of five conversions.

  1. Step 1 of 5

    Sound is moving air pressure.

    Something vibrates Pressure wavesreach your ear

    A vibrating object squeezes and stretches the air around it, and that pattern travels outward. Hearing is detecting those pressure changes.

  2. Step 2 of 5

    The eardrum vibrates in step.

    The sound Pressure pattern in airThe eardrum The same pattern, asmovement

    A thin membrane, tightly stretched, moves in and out exactly matching the arriving pressure. It copies the sound faithfully as motion.

  3. Step 3 of 5

    Three tiny bones amplify it.

    1 Eardrum moves2 Three boneslever it up3 A much strongerpush

    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.

  4. Step 4 of 5

    A coiled tube sorts out the pitch.

    High notes Shake the entranceLow notes Travel to the far end

    The cochlea is a fluid-filled spiral. High notes shake the near end, low notes the far end — so position along it means pitch.

  5. Step 5 of 5

    Hair cells make the nerve signals.

    Inside the cochlea Hair cells bending — andthey do not regrow

    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.

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