# A sealed syringe contains a fixed mass of air. When the plunger is pushed in quickly, the temperature of the air inside rises. Explain why the temperature of the air increases when the volume is reduced.

> Eduqas A-Level Physics — 3.4 Thermal physics · Explain · 5 marks

> A student pushes the plunger of a sealed syringe inward, reducing the volume of the trapped air. The student notices the outside of the syringe feels warm after compression.

## Mark scheme (5 marks)

1. The air particles are compressed into a smaller volume
2. Work is done on the gas / energy is transferred to the gas by the plunger
3. This energy increases the internal energy of the gas
4. The particles move faster / have greater kinetic energy
5. Higher average kinetic energy of particles means a higher temperature

## Key terms

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

## Related

- [Revision notes for Eduqas A-Level Physics](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-sealed-syringe-contains-a-fixed-97a36ddc) · Published by Druglandscape Ltd.