Electricity and Magnetism — Answer Key
Part A: Fill in the Blank
Write the missing word or number on each line.
1. In a simple circuit, the battery is the source of electrical energy.
A battery pushes electricity through the wires to power the circuit.
2. Electricity moves from the battery through the wires to the bulb.
Wires are the path that carries electricity between parts of a circuit.
3. When you flip a switch off, the circuit becomes open and the bulb goes dark.
A switch opens or closes a circuit to control the flow of electricity.
4. A bulb lights up because electrical energy changes into light and heat.
The bulb turns electrical energy into light energy that we can see.
5. If any wire in a circuit is broken, the circuit is open.
An open circuit has a gap, so electricity stops flowing and the bulb is off.
6. A metal paper clip can close a broken circuit because metal is a good conductor.
Conductors like metal paper clips let electricity flow across a small gap.
7. A rubber eraser in a circuit would act like an insulator and stop the flow.
Rubber is an insulator, so electricity cannot move through it.
8. A circuit with a battery, wire, and bulb all connected is a closed circuit.
A closed circuit has no gaps, so electricity flows and the bulb lights.
9. The plastic around a wire is there to keep you safe because it is an insulator.
Plastic insulation keeps electricity inside the wire and away from skin.
Part B: Matching
Match each item on the left to the correct answer on the right.
1. Match each item to its correct answer.
Battery
→ Source of electrical energy in a circuit
Source of electrical energy in a circuit
Wire
→ Thin metal path that carries electricity
Thin metal path that carries electricity
Bulb
→ Part that changes electricity into light
Part that changes electricity into light
Switch
→ Control that opens or closes a circuit
Control that opens or closes a circuit
Each part of a Grade 3 circuit has a special job that makes the bulb light up.