Year 4 science · Key Stage 2 · Electricity
Year 4 electricity: simple circuits, conductors and insulators
In Year 4 science, children learn which everyday appliances run on electricity and build their first simple series circuits with cells, wires, bulbs, switches and buzzers. They work out why a bulb lights only when it is part of a complete loop with a cell, how a switch opens and closes the loop, and which materials let electricity pass through them.
Simple circuits and conductors, explained
Children begin by sorting appliances at home and in school, such as lamps, toasters, torches and toys, into those that use mains electricity from a wall socket and those that run on batteries. They then build circuits with real components. A cell is a single unit that stores electrical energy, such as the AA “battery” in a remote control. Strictly, a battery is two or more cells joined together, but in everyday speech a single cell is often called a battery too, and schools tend to use both words. Children learn the names of the parts: cells, wires, bulbs (or lamps), switches, buzzers and, in some schools, motors. They draw circuits as pictures of the real components. Circuit symbols are introduced later, in Year 6.
The main idea of the topic is the complete loop. A series circuit is one loop, with the components joined one after another. A bulb will only light if the circuit forms a complete loop that includes the cell, the bulb and all the wires, with no gaps. If a wire is loose, a connection is missed, or a component is joined to the cell at one end only, the bulb stays off. Children test circuits, predict whether a bulb will light, and fix circuits that are broken. Many pupils start by guessing that one wire from the cell to the bulb is enough, and the best learning comes from discovering that it is not.
A switch is simply a controlled gap. When the switch is open, there is a gap in the loop and the bulb is off. When it is closed, the gap is filled, the loop is complete and the bulb lights. This is why a light switch at home turns the light on and off. Children also notice that adding more cells in the same circuit usually makes a bulb brighter, although current and voltage may be mentioned but are not formally defined at this stage.
The last part is testing materials. Children make a gap in a circuit and put different objects across it. If the bulb lights, the object is a conductor, a material that lets electricity pass through. If it stays off, the object is an insulator. They discover that metals are good conductors, while plastic, wood, glass, rubber and fabric are insulators. Alongside this, teachers teach how to work safely with electricity: only batteries are used in classroom experiments, because mains electricity from a socket is powerful enough to cause serious harm.
Words your child will hear
- Cell and battery
- A cell stores electrical energy, such as an AA. Strictly, two or more cells joined together make a battery, though a single cell is often called a battery too.
- Series circuit
- A single loop in which the parts are joined one after another.
- Complete circuit
- A loop with no gaps, so electricity can flow all the way round.
- Switch
- A part that opens or closes a gap in a circuit to turn it off or on.
- Conductor
- A material that lets electricity pass through it easily, such as most metals.
- Insulator
- A material that does not let electricity pass through it easily, such as plastic or wood.
- Buzzer
- A part that makes a noise when it is in a complete circuit.
What the National Curriculum says
In Year 4, pupils should be taught to:
- Identify common appliances that run on electricity
- Construct a simple series electrical circuit, identifying and naming its basic parts, including cells, wires, bulbs, switches and buzzers
- Identify whether or not a lamp will light in a simple series circuit, based on whether or not the lamp is part of a complete loop with a battery
- Recognise that a switch opens and closes a circuit and associate this with whether or not a lamp lights in a simple series circuit
- Recognise some common conductors and insulators, and associate metals with being good conductors
Objectives from the National Curriculum in England, © Crown copyright, used under the Open Government Licence v3.0.
A worked example
Each circuit has a cell, a bulb and wires. Circuit A is a complete loop with a closed switch. Circuit B is a complete loop but the switch is open. Circuit C has a wire from the cell to one side of the bulb, but the other side of the bulb is not joined to anything. Which bulbs will light? Then, in circuit B, which object could close the gap in place of the switch: a bare metal paper clip, a wooden peg or a plastic spoon?
- Circuit A. Follow the loop with a finger from the cell, along the wire, through the switch and bulb, and back to the cell. The route has no gaps and the switch is closed, so the bulb lights.
- Circuit B. Follow the loop again. The open switch is a gap, so the electricity cannot get all the way round. The bulb does not light.
- Circuit C. Following the route, the loop stops at the end of the bulb that is not joined to anything. Because the loop is not complete, the bulb stays off. One wire is not enough.
- Closing the gap in B. Put each object across the gap in turn, touching both ends. A bare metal paper clip is a conductor, so it completes the loop and the bulb lights. A wooden peg and a plastic spoon are insulators, so they leave the gap and the bulb stays off.
Only the bulb in circuit A lights. In circuit B, the bare metal paper clip would make the bulb light, but the wooden peg and plastic spoon would not.
Common mistakes and how to help
Thinking one wire from the cell to the bulb is enough
Children think of electricity as something that flows from the cell into the bulb and gets used up, like water into a bucket. A circuit needs a way back as well as a way there.
What helps: Ask your child to trace the route round the whole loop with a finger and say where it starts and finishes. If they can’t come back to the cell, the circuit has a gap.
Thinking an “open” switch means the light is on
In daily life, an open shop is working and a closed shop is not. For a circuit, it is the opposite: an open switch has a gap, and the light is off.
What helps: Describe a switch as a drawbridge. Raised (open), nothing can cross; lowered (closed), the path is complete. Say “closed means the loop is closed up”.
Assuming shiny things, or all metal things, will conduct
Pupils learn that metals are good conductors. Then they find that a painted or plastic-coated metal item does not light the bulb. Shiny plastic that only looks like metal confuses things further.
What helps: Test a plastic-coated paper clip and then a bare metal one. Explain that the coating is an insulator that covers the metal underneath, so the electricity cannot reach it.
Believing the bulb nearest the cell gets all the electricity, or that electricity gets “used up” before the end
Children picture electricity as a thing that travels round and gets spent. In a series circuit, the same amount flows all the way round the loop.
What helps: Build a circuit with two bulbs and show that they come on together, not one after the other. Note that adding another bulb in the loop makes each one dimmer, but both still light.
How to help at home
- Appliance sort. Walk round your home and sort what you see into things that run on mains electricity, things that run on batteries and things that use neither. Talk about which can be used away from a socket and why some battery items, such as phones, need recharging.
- Build a torch circuit. With a small battery pack, a bulb holder, a switch and some short wires from a hobby kit, or borrowed from school, build a circuit together. Let your child predict what will happen before each connection. Stay with them and use only ordinary AA or AAA batteries, never mains. Never join the two ends of a battery with just a wire, because it can get hot, and keep small button batteries away from younger children.
- Conductor or insulator? Using a working battery-and-bulb circuit with a gap, test everyday objects such as a coin, a metal spoon, a key, a piece of kitchen foil, a rubber band, a plastic ruler and an eraser. First predict, then test, and sort the results into two groups. Ask your child what the conductors have in common.
- Talk about electrical safety. Agree simple rules together: never put anything into a socket, never use electrical appliances near water, and keep cables tidy. Ask your child to explain why a metal object pushed into a socket is so dangerous.
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