Electricity and Magnetism — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. A closed circuit has no gaps so electricity flows all the way around.
A closed circuit is a complete loop that lets electricity flow.
2. An open circuit has a break, so the bulb will not light.
An open circuit is broken, so electricity cannot reach the bulb.
3. A material that lets electricity flow through it is called a conductor.
Conductors like copper wire allow electricity to move through them easily.
4. A material that stops electricity from flowing is called an insulator.
Insulators block the flow of electricity and keep people safe.
5. A switch can open or close a circuit by pressing or flipping it.
A switch controls whether a circuit is open or closed.
6. Copper is a metal that is a very good conductor of electricity.
Copper allows electricity to flow through it, making it a strong conductor.
7. Wires are usually covered with plastic to act as an insulator.
Plastic is an insulator, so it stops electricity from leaving the wire.
8. The part of a circuit that gives off light is the bulb.
The bulb turns electrical energy into light in a circuit.
9. A battery is the power source that pushes electricity around a circuit.
A battery provides the energy that moves electricity through the circuit.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Closed circuit
→ A complete loop where electricity flows
A complete loop where electricity flows
Open circuit
→ A broken path so the bulb stays off
A broken path so the bulb stays off
Conductor
→ Copper wire that carries electricity
Copper wire that carries electricity
Insulator
→ Rubber that stops electricity from passing
Rubber that stops electricity from passing
Knowing these Grade 3 circuit words helps you explain how electricity moves or is stopped.