A conductor lets electric current pass through it; an insulator does not. Metals such as copper, iron, steel, aluminium and brass are conductors, and so is graphite. Rubber, plastic, wood, glass, paper, cotton, wool, cork and ceramic are insulators. Wires are copper inside (to carry current) and plastic outside (to keep it in and keep us safe). A simple tester — a cell, a bulb and a gap — shows which is which: the bulb glows only when a conductor bridges the gap.
Metal passes, plastic blocks — “metals and graphite conduct; rubber, plastic, wood, glass and paper insulate”
Conductors: metals (copper, iron, steel, aluminium, brass) and graphite.
Insulators: rubber, plastic, wood, glass, paper, cotton, wool, cork, ceramic and dry air.
Tester: put the object across the gap — the bulb glows only for a conductor.
Use it for: Science lessons on conductors and insulators, making a circuit tester with a battery kit and an adult.
Worked example: 🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a steel spoon across the gap. Does the bulb glow? → Yes
Steel is a metal, so the spoon is a conductor.
It closes the gap, current flows round the loop and the bulb glows.
Check: A plastic straw in the same gap: the bulb stays dark ✓
Work it out in your head or on paper, then tap your answer — or type it and press Check. Stuck? Press “Show me how”.
Right: 0 · Tried: 0
🏁 Lesson 3 test
20 questions. Check each answer, then go to the next one. Get 16 or more right to pass.
🏅 Sign in with Google to earn the
🥄 Conductor Detective badge when you pass — and a certificate when you finish all 10 lessons of
Part 1 · Electricity basics. You can still take the test without signing in.
🖨️ Electronics Worksheet: Conductors and Insulators
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