Electricity and Circuits (KS2 Science)

SC15Electricity and Circuits

A complete loop for electricity to flow.

A circuit needs a complete loop from a power source through components and back.

A simple circuit.

complete → bulb lights

gap → no flow

A break anywhere stops the flow — that's exactly how a switch works.

Learn the Circuit

1A cell provides the push.

A cell (or battery) pushes electricity around the circuit. Wires (conductors) carry it.

🔋 cell

2The loop must be complete.

Electricity only flows in a complete, unbroken loop. A gap anywhere stops it — the bulb goes out.

complete loop

3Switches and components.

A switch opens (breaks) or closes (completes) the loop. Bulbs light, buzzers sound, motors spin — each needs the loop closed.

switch = gap control

💡 Key IdeaAdding more cells makes the bulb brighter (more push); adding more bulbs in one loop makes each dimmer (the push is shared).

Worked Example

A bulb won't light. What are the things to check?

The loop

is the circuit complete, with no gaps or loose wires?

→

The cell

is the battery working and the right way round?

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✓ The parts

is the bulb broken? Is the switch closed?

Watch Out! Common Mistakes

‘One wire is enough.’

It’s a loop! Electricity needs a complete circuit — out from the cell, through the component, and back. One wire alone can’t light a bulb.

Touching a mains socket to ‘test’.

Never! Mains electricity is dangerous. School circuits use safe low-voltage cells. Never experiment with wall sockets.

‘Plastic conducts electricity.’

It insulates! Metals conduct electricity; plastic, wood and rubber are insulators — which is why wires have plastic coating for safety.

⬇ Cheat Sheet

ELECTRICITY AND CIRCUITS

A cell/battery pushes electricity through the circuit.
Electricity flows only in a complete, unbroken loop.
A switch breaks or completes the loop.
More cells = brighter; more bulbs in one loop = dimmer. Metals conduct; plastic insulates.

Example: a gap in the loop (open switch) → bulb off.

📖 Continue Your Journey

✓ SC1 Classifying Living Things ✓ SC2 Habitats and Adaptation ✓ SC3 Food Chains and Webs ✓ SC4 The Skeleton and Muscles ✓ SC5 Digestion and Teeth ✓ SC6 The Circulatory System ✓ SC7 Plants and Photosynthesis ✓ SC8 Life Cycles and Reproduction ✓ SC9 States of Matter and the Water Cycle ✓ SC10 Materials and Their Properties ✓ SC11 Reversible and Irreversible Changes ✓ SC12 Forces and Magnets ✓ SC13 Light and Shadows ✓ SC14 Sound SC15 Electricity and Circuits SC16 Earth and Space

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Next Lesson: SC16 Earth and SpaceA spinning, orbiting world.

📄 Free printable: Download the Electricity and Circuits cheat sheet (PDF) — keep it by your child's desk.

Quick summary

A cell or battery pushes electricity around the circuit.
Electricity flows only in a complete, unbroken loop.
A switch works by breaking or completing the loop.
More cells make bulbs brighter; metals conduct, plastics insulate.

Frequently asked questions

What makes a bulb light in a circuit?

A complete, unbroken loop from the cell, through the bulb, and back. Any gap — including an open switch — stops the flow and the bulb goes out.

How does a switch work?

It opens a gap in the circuit (off) or closes it to complete the loop (on), controlling whether electricity can flow.

What are conductors and insulators in circuits?

Conductors (metals) let electricity flow and are used for wires; insulators (plastic, rubber) block it and are used for safe coverings.