# A student heats a block of ice at 0 °C until it completely melts into water at 0 °C.

Explain, using the particle model, the changes to the internal energy and the arrangement of particles during this process.

> OCR GCSE Physics A: Gateway Science (J249) — P1 Matter · Explain · 4 marks

## Mark scheme (4 marks)

1. The internal energy of the substance increases.
2. This increase in internal energy is due to an increase in the potential energy of the particles.
3. The energy supplied is used to overcome the forces of attraction between the particles.
4. The particles change from a fixed, regular arrangement to a random, disordered arrangement, allowing them to slide past each other.

## 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)
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Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-heats-a-block-of-135a2818) · Published by Druglandscape Ltd.