# A loudspeaker produces a sound wave that travels through air. Describe what happens to the air particles as the sound wave passes through them, and explain how this creates regions of compression and rarefaction.

> Eduqas A-Level Physics — 2.5 Wave properties · Describe and Explain · 5 marks

> Sound waves are an example of a type of wave that transfers energy through a medium by causing particles to vibrate.

## Mark scheme (5 marks)

1. Air particles vibrate back and forth (oscillate) in the same direction as the wave is travelling
2. This makes sound a longitudinal wave
3. A compression is where particles are pushed closer together / regions of higher pressure
4. A rarefaction is where particles are spread further apart / regions of lower pressure
5. Energy is transferred in the direction of wave travel without the particles themselves moving permanently from their position / particles return to their original positions

## Key terms

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

## Related

- [Revision notes for Eduqas A-Level Physics](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and 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/a-loudspeaker-produces-a-sound-wave-d8e89ef2) · Published by Druglandscape Ltd.