# A student charges a balloon by rubbing it against their hair. The balloon is then held close to, but not touching, a thin stream of water from a tap. Explain why the stream of water is attracted towards the balloon.

> Edexcel A-Level Physics (9PH0) — 11.1 Radioactivity, fission and fusion · Explain · 5 marks

> When a balloon is rubbed against hair, electrons are transferred from the hair to the balloon. The balloon is then held near a thin stream of water without touching it.

## Mark scheme (5 marks)

1. Rubbing transfers electrons from the hair to the balloon, giving the balloon a negative static charge
2. The negatively charged balloon creates an electric field around it
3. The negative charge on the balloon repels electrons in the water, so the surface of the water nearest the balloon becomes positively charged (induced charge / charge separation / induction)
4. Unlike (opposite) charges attract, so the positive region of the water is attracted to the negative balloon
5. This is a non-contact (electrostatic) force — the balloon does not need to touch the water to exert a force on it

## Related

- [Revision notes for Edexcel A-Level Physics (9PH0)](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-charges-a-balloon-by-a4127083) · Published by Druglandscape Ltd.