# Explain why sound waves are able to travel through both solids and liquids, but S-waves can only travel through solids.

> AQA GCSE Physics (8463) — 4.6.1 Waves in air, fluids and solids · Explain · 4 marks

> Seismic waves produced by earthquakes include two types: P-waves and S-waves. Scientists use these waves to learn about the structure of the Earth's interior.

## Mark scheme (4 marks)

1. S-waves are transverse waves (oscillations perpendicular to the direction of travel)
2. Transverse waves / S-waves cannot travel through liquids because liquids cannot transmit sideways/shear oscillations
3. Sound waves (and P-waves) are longitudinal waves (oscillations parallel to the direction of travel)
4. Longitudinal waves can travel through liquids because the back-and-forth oscillations (compressions and rarefactions) can be transmitted through any medium that can be compressed

## Key terms

- [S-waves](https://www.gradenine.co.uk/glossary/s-waves)

## Related

- [Revision notes for AQA GCSE Physics (8463)](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-sound-waves-are-able-b30a2152) · Published by Druglandscape Ltd.