Purpose
Classify materials as conductors, insulators, or somewhere in between, and relate the result to atomic structure.
Safety
Battery packs only — never wall current. If a wire or material gets warm, disconnect immediately.
Materials
- Battery pack, lamp or buzzer, alligator leads
- Test materials: copper wire, aluminium foil, graphite pencil lead, steel nail, glass rod, plastic ruler, rubber band, tap water, salt water, distilled water, wood, a coin
Procedure
- Build a simple circuit with a gap in it.
- Bridge the gap with each material and record how brightly the lamp lights.
- For liquids, use two electrodes a fixed distance apart — keep it identical for every liquid.
Data
| Material | Lamp brightness (none / dim / bright) | Classification |
|---|---|---|
| Copper wire | ||
| Aluminium foil | ||
| Pencil lead (graphite) | ||
| Glass rod | ||
| Plastic ruler | ||
| Tap water | ||
| Salt water | ||
| Distilled water |
Analysis
- What do the conductors have in common structurally?
- Distilled water conducts poorly; salt water conducts well. The water is the same — so what is carrying the charge? See Ions and Ionic Compounds.
- Graphite is a non-metal that conducts. Look up why, and say what that shows about “metals conduct, non-metals do not”.
Hand in
- Data table with all materials classified
- Analysis answers
- One material you would test next, and your prediction
Curriculum connection
D2.2
determine the conductivity of various materials by investigating their ability to hold or transfer electric charges
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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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