# A kettle is used to heat water. Describe the energy changes that take place from when the kettle is switched on until the water reaches its maximum temperature. Include reference to useful energy and waste energy in your answer.

> AQA GCSE Physics (8463) — 4.1.1 Energy changes in a system, and the ways energy is stored before and after such changes · Describe · 4 marks

## Mark scheme (4 marks)

1. Electrical energy is transferred to thermal energy (in the water / heating element)
2. The useful energy transfer is the thermal energy that raises the temperature of the water
3. Some energy is wasted / dissipated (e.g. as thermal energy lost to the surroundings / sound)
4. The total energy input equals the useful energy output plus the waste energy (conservation of energy / energy cannot be created or destroyed)

## Key terms

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

## Related

- [Revision notes for AQA GCSE Physics (8463)](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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/a-kettle-is-used-to-heat-4cdf7fde) · Published by Druglandscape Ltd.