# A nurse presses the plunger of a sealed syringe, reducing the volume of the air trapped inside. Explain why the temperature of the air inside the syringe increases when the plunger is pushed in.

> OCR GCSE Physics A: Gateway Science (J249) — P1.1 The particle model · Explain · 4 marks

> A sealed syringe contains a fixed amount of air. When the plunger is pushed inwards, the volume of the trapped air decreases.

## Mark scheme (4 marks)

1. The volume of the air decreases, so the particles collide with the walls more frequently
2. Work is done on the gas / a force is applied to the gas by the plunger
3. This transfers energy to the particles, increasing their kinetic energy
4. Temperature is a measure of the average kinetic energy of the particles, so temperature increases

## Key terms

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

## Related

- [Revision notes for OCR GCSE Physics A: Gateway Science (J249)](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-nurse-presses-the-plunger-of-219bbfc6) · Published by Druglandscape Ltd.