# A loudspeaker produces a sound wave that travels through air. Describe the nature of a sound wave, including how energy is transferred and what happens to the air particles as the wave passes through them.

> Eduqas A-Level Physics — 2.4 The nature of waves · Describe · 5 marks

## Mark scheme (5 marks)

1. Sound is a longitudinal wave
2. The air particles vibrate parallel to the direction of wave travel / energy transfer
3. The wave produces compressions (regions where particles are pushed closer together)
4. The wave produces rarefactions (regions where particles are spread further apart)
5. Energy is transferred in the direction of wave travel but the air particles are not permanently displaced / do not travel with the wave

## Related

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

---
Source: [GradeNine](https://www.gradenine.co.uk/q/a-loudspeaker-produces-a-sound-wave-84b8c731) · Published by Druglandscape Ltd.