# Explain how the structures of the ear convert sound waves in air into electrical signals sent to the brain.

> AQA A-Level Physics (7408) — 3.10.2 Physics of the Ear · Explain · 5 marks

> Sound waves travelling through air reach the outer ear and are eventually converted into nerve impulses detected by the brain.

## Mark scheme (5 marks)

1. Sound waves cause the eardrum (tympanic membrane) to vibrate
2. The ossicles (three small bones / hammer, anvil and stirrup) transmit and amplify the vibrations
3. The ossicles cause the oval window to vibrate, transmitting vibrations into the cochlea
4. Vibrations in the fluid inside the cochlea stimulate hair cells
5. Hair cells generate / produce electrical signals (nerve impulses) that are sent to the brain via the auditory nerve

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