# A student places their ear against a long metal railway track and hears a distant train's vibrations through the metal before hearing the same sound through the air. Explain why the student hears the sound through the metal first, and state what type of wave sound is.

> Cambridge International IGCSE Physics (0625) — 3.4 Sound · Explain · 4 marks

> Sound travels through solids, liquids, and gases, but its speed differs between these media.

## Mark scheme (4 marks)

1. Sound travels faster in metal/solids than in air/gases
2. Because the metal is a more rigid/denser medium, particles are closer together so energy is transferred more quickly
3. Sound travels the same distance through both media (the length of the track), so the one that arrives first must have travelled faster
4. Sound is a longitudinal wave

## Key terms

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

## Related

- [Revision notes for Cambridge International IGCSE Physics (0625)](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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-places-their-ear-against-ef7383eb) · Published by Druglandscape Ltd.