# A student rubs a plastic rod with a woollen cloth. The plastic rod becomes negatively charged. Explain why the rod becomes negatively charged and describe the charge left on the woollen cloth after rubbing.

> Edexcel GCSE Physics (1PH0) — 11.1 Static electricity (Phys only) · Explain · 4 marks

> Plastic and wool are both insulators. When they are rubbed together, a static charge can build up on each material.

## Mark scheme (4 marks)

1. Electrons are transferred from the woollen cloth to the plastic rod (by friction / due to rubbing)
2. The plastic rod gains electrons, giving it an excess of negative charge
3. The woollen cloth loses electrons, leaving it with a positive static charge
4. The effect occurs because both materials are insulators, so electrons cannot flow away and the charge remains / builds up

## Related

- [Revision notes for Edexcel GCSE Physics (1PH0)](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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/a-student-rubs-a-plastic-rod-11d2be40) · Published by Druglandscape Ltd.