# A student places a hot drink in a polystyrene cup and the same volume of equally hot drink in a thin metal cup. After ten minutes, the drink in the metal cup has cooled to a much lower temperature than the drink in the polystyrene cup. Explain why the drink in the metal cup cools more quickly.

> WJEC A-Level Physics (Wales) — 3.4 Thermal physics · Explain · 5 marks

> Polystyrene is a thermal insulator. Metal is a good thermal conductor.

## Mark scheme (5 marks)

1. Heat/thermal energy is transferred from the hot drink to the cup
2. Metal is a good thermal conductor so it allows thermal energy to pass through it easily / quickly
3. Thermal energy is then transferred from the outer surface of the metal cup to the surroundings / air
4. Polystyrene is a thermal insulator so it does not allow thermal energy to pass through it easily
5. So the drink in the polystyrene cup loses thermal energy more slowly / at a lower rate, keeping it hotter for longer

## Related

- [Revision notes for WJEC A-Level Physics (Wales)](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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