# A student heats a fixed mass of ice at a steady rate. The ice melts and then the water warms up. Explain what happens to the internal energy of the substance during each of these two stages, and why the temperature behaves differently in each stage.

> WJEC A-Level Physics (Wales) — 2.3 Capacitance (A-Level only) · Explain · 5 marks

## Mark scheme (5 marks)

1. Internal energy increases during melting
2. During melting, the energy supplied increases the potential energy of the particles (bonds/intermolecular forces are broken/overcome), not the kinetic energy
3. Because kinetic energy of the particles does not increase during melting, the temperature does not rise
4. Internal energy continues to increase as the liquid water warms up
5. During warming of the liquid, energy supplied increases the kinetic energy of the particles, so temperature rises

## Key terms

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

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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-heats-a-fixed-mass-693039f2) · Published by Druglandscape Ltd.