# A student fills a rigid metal container with air and seals it. The container is then placed in a pan of boiling water. Explain why the pressure of the gas inside the container increases as the temperature rises.

> WJEC A-Level Physics (Wales) — 4.1 Thermal physics · Explain · 5 marks

> A rigid metal container is sealed at room temperature and then heated in boiling water.

## Mark scheme (5 marks)

1. The gas molecules move faster (have greater kinetic energy) when temperature increases
2. The molecules collide with the walls of the container more frequently
3. The molecules hit the walls of the container with greater force
4. The volume of the container stays constant (because it is rigid)
5. More frequent and more forceful collisions per unit area of the walls result in 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 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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-fills-a-rigid-metal-6888fe80) · Published by Druglandscape Ltd.