Explain why a balloon that has been rubbed against a woollen jumper sticks to a wall.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
When a balloon is rubbed against a woollen jumper and then held close to a wall, it clings to the wall's surface without falling.
Model answer (4 marks)
Rubbing the balloon against the woollen jumper transfers electrons from the jumper to the balloon, giving the balloon a negative static charge.
The negative charge on the balloon induces a positive charge on the surface of the wall.
Opposite charges attract, so the balloon is pulled towards the wall and sticks.
The negative charge on the balloon induces a positive charge on the surface of the wall.
Opposite charges attract, so the balloon is pulled towards the wall and sticks.
Examiner tips
- Use the exact wording from the mark scheme (e.g. "transfers electrons", "negative static charge", "induces opposite charges", "attract"),
- Show the cause–effect chain clearly: transfer → charge → induction → attraction.
- Keep the answer to 4 short sentences, one for each point.
Mark scheme (4 marks)
- Rubbing transfers electrons from the jumper to the balloon
- The balloon gains a negative static charge (because it has gained electrons)
- The charged balloon induces / attracts opposite charges in the surface of the wall
- Opposite charges attract, so the balloon is pulled towards the wall (electrostatic force of attraction)
Related
- All AQA GCSE Physics (8463) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
More Static electricity (Phys only) questions
- Explain why a plastic rod becomes negatively charged when rubbed with a cloth.
- A van de Graaff generator builds up a large static charge on its metal dome. A s…
- A student rubs a perspex rod with a silk cloth. Explain why the perspex rod beco…
- Explain why a spark is produced when a person who has built up a static charge r…