# Explain why sounds travelling through air are difficult to transmit into the fluid-filled cochlea, and describe how the ear overcomes this problem.

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

## Mark scheme (5 marks)

1. Sound travels through air (a low-density / less dense medium) and must enter fluid (a denser / more dense medium)
2. Most sound energy is reflected / lost at the air–fluid boundary without the middle ear
3. The ossicles (hammer / anvil / stirrup) transmit and amplify vibrations from the eardrum to the oval window
4. The oval window has a much smaller area than the eardrum, concentrating force / increasing pressure
5. The increased pressure allows sufficient energy to be transferred into the cochlea fluid / overcomes the impedance mismatch

## Key terms

- [cochlea](https://www.gradenine.co.uk/glossary/cochlea)

## Related

- [Revision notes for AQA A-Level Physics (7408)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-sounds-travelling-through-air-fb7dc3dd) · Published by Druglandscape Ltd.