# A football is left outside on a cold winter night. When the ball is brought back indoors into a warm room, it feels harder. Explain why the pressure inside the football increases when its temperature rises. Assume the volume of the football does not change.

> WJEC GCSE Physics (Wales) — 2.3 Forces and motion · Explain · 4 marks

## Mark scheme (4 marks)

1. The gas particles (molecules) inside the football move faster / have greater kinetic energy at a higher temperature
2. The particles collide with the walls of the football more frequently
3. The particles also collide with the walls with greater force
4. Pressure is the perpendicular force per unit area on the walls, so greater force from collisions means greater pressure

## Key terms

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

## Related

- [Revision notes for WJEC GCSE 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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Source: [GradeNine](https://www.gradenine.co.uk/q/a-football-is-left-outside-on-728be624) · Published by Druglandscape Ltd.