Purpose
Observe charging by friction, conduction, and induction, and explain each using the movement of electrons.
Materials
- Balloons, wool, silk, acetate and vinyl strips
- Pith ball on a thread, electroscope, aluminium can, thin water stream
Stations
| # | Do this | Explain |
|---|---|---|
| 1 | Rub a balloon on wool; hold near hair | Which way did electrons move? |
| 2 | Charged balloon near a thin stream of water | Water is neutral — so why does it bend? |
| 3 | Charged rod near, then touching, an electroscope | Induction, then conduction |
| 4 | Charged rod rolls an empty can without touching | Induced charge separation |
| 5 | Two rods rubbed on the same cloth, brought together | Predict before you look |
Data
| Station | Observation | Charge transferred? | Method |
|---|---|---|---|
| 1 | |||
| 2 | |||
| 3 | |||
| 4 | |||
| 5 |
Analysis
- In station 1, which object gained electrons? How can you tell?
- Station 2 is the subtle one. The water is neutral overall — write a full explanation using induced charge separation.
- Why does this whole lab work badly on a humid day? See Static Electricity.
Hand in
- Data table
- A labelled diagram of station 4 showing where charges sit
- Analysis answers
Curriculum connection
D2.1
conduct investigations to explain the behaviour of electric charges in static and current electricity, and to relate the observed behaviour to the properties of subatomic particles and atomic structure
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A1.2
apply a scientific experimentation process and associated skills to conduct investigations, making connections between their observations and findings and the scientific concepts they are learning
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