# A student cools a sample of liquid wax until it becomes solid. Explain what happens to the internal energy of the wax during this process, referring to both kinetic energy and potential energy of the particles.

> AQA GCSE Physics (8463) — 4.3.2 Internal energy and energy transfers · Explain · 4 marks

## Mark scheme (4 marks)

1. The internal energy of the wax decreases (as it cools and solidifies).
2. The kinetic energy of the particles decreases as the temperature falls.
3. During the change of state (freezing), the temperature stays constant so the kinetic energy of the particles does not change.
4. During the change of state, the potential energy of the particles decreases as the particles move into more ordered/fixed positions.

## Key terms

- [internal energy](https://www.gradenine.co.uk/glossary/internal-energy)
- [kinetic energy](https://www.gradenine.co.uk/glossary/kinetic-energy)
- [potential energy](https://www.gradenine.co.uk/glossary/potential-energy)

## Related

- [Revision notes for AQA GCSE Physics (8463)](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-student-cools-a-sample-of-8416b5ae) · Published by Druglandscape Ltd.