# Evaporation and boiling are both processes by which a liquid changes to a vapour. Describe TWO differences between evaporation and boiling.

> Pearson Edexcel International GCSE Physics (4PH1) — 5.2 Change of state · Describe · 4 marks

> A puddle of water left on a pavement on a warm day gradually disappears, even though the water never reaches 100 °C.

## Mark scheme (4 marks)

1. Evaporation occurs at any temperature, whereas boiling only occurs at the boiling point of the liquid
2. Evaporation occurs only at the surface of the liquid, whereas boiling occurs throughout the whole liquid
3. During evaporation, only the higher-energy molecules escape from the surface, so the average kinetic energy of the remaining molecules decreases
4. Boiling requires a continuous external heat supply to maintain the boiling point temperature, whereas evaporation can occur without an external heat source

## Key terms

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

## Related

- [Revision notes for Pearson Edexcel International GCSE Physics (4PH1)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" 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/evaporation-and-boiling-are-both-processes-19dca0bb) · Published by Druglandscape Ltd.