Here we focus on those scientific concepts that are the hardest to explain to children. We break it down into what pupils need to know and outline the background science. Even though much of the background science does not need to be taught to primary aged children, it is useful for you as a teacher when addressing misconceptions and children’s challenging questions. 

Please refer to your national curriculum documents when planning your sequence of work and ensure that you teach the correct knowledge for your year group. 

What do children need to know about electricity?

Learning about electricity should be as exploratory, hands-on and pupil-led as possible. We have included some ideas for how to teach electricity in part two of this topic guide.

Key scientific concepts: Pupils need to know... 

1. Some appliances need electricity to work.
2. Materials which can successfully complete an electric circuit are called electrical conductors and those which can not are called insulators. Insulating materials are used to protect us from the dangers of electricity.
3. A simple circuit is a collection of components, connected in a loop of conducting material, with a power supply.
4. Switches are used to control simple circuits.
5. Changing the voltage of a power supply affects components in a circuit.

1. Some appliances need electricity to work.

Pupils need to know:

• We use electrical appliances to help us.
• Electrical appliances contain electric circuits and need to be connected to a power supply (batteries or mains electricity) to work.
• Electrical appliances and mains electricity can be dangerous.
• Mains electricity usually comes from power stations, some of which burn polluting fuels. We also have to pay for the electricity we use so we should be careful to not waste it.

Background Science for Teachers

Children will be aware of the electrical appliances in their daily lives and that they either need batteries or to be plugged into a socket to work. Electrical appliances need a complete electric circuit in order to operate. In an electric circuit there needs to be a voltage that pushes the electricity (electric current) around a complete loop of conducting material. This voltage can be provided by the mains electricity supply or by batteries. 

The way electricity is created by batteries is different to the way it is produced in power stations and transmitted to eventually come out of a socket in our home.

A Venn diagram illustrating where electricity is used in the home, comparing the use of batteries and mains electricity. 

Image credit: Amanda Poole. Licensed only for use on Explorify.

A battery is two or more cells, where a cell is constructed from two electrodes made of different metals or carbon, separated by a liquid called an electrolyte. The voltage is created by a chemical reaction between the metals and the electrolyte, and the cell will become 'flat' or depleted when the chemicals have all been used up. This chemical reaction causes one the electrodes to become positive and the other negative, this is why the two ends of a battery are marked positive and negative. 

When a battery is connected in a complete loop of conducting material such as electrical wires, tiny negative particles called electrons are pushed from the negative terminal of the battery towards the positive terminal, this is an electric current, the electrons flow around the circuit and through any components in their path.

Mains electricity is made at power stations by huge generators or generated by solar cells.

Power stations can use wind, steam, or moving water to create movement in the generator. Generators in a power station produce electricity when a coil of wire is in a changing magnetic field. This changing magnetic field is caused by making a magnet spin inside the coil. Fossil fuel (oil, natural gas, coal) and nuclear power stations heat water and produce steam to turn a turbine which is connected to the magnet inside the generator, causing it to spin. This short BBC film compares different sources and explain how power stations work. (This film is longer but has physical demonstrations.)

A diagram illustrating where electricity is made and how it is directed to our homes. 

Image credit: Amanda Poole. Licensed only for use on Explorify.

Mains electricity is transported across the UK via the National Grid using huge cables supported by pylons. The voltage across the cables is around 400,000V to help keep currents low, stopping the cables from heating and energy being wasted. The voltage has to be made safer before it enters our homes, so it is reduced to 230V but this is still dangerous, so we have many safety measures preventing electrical fires or electrocution such as earth wires, fuses, and insulating materials on wires and appliances.

2. Materials that can successfully complete an electric circuit are called electrical conductors.

Pupils need to know:

• A material that can be used successfully to complete an electric circuit is called an electrical conductor.
• A material that cannot complete an electric circuit is called an electrical insulator.
• Metals are conductors, as are a few other materials (e.g. graphite, salt solutions).
• Plastics, ceramics and air are insulators.

Background Science for Teachers

A simple electric circuit consists of a single device connected by wires to the two terminals of a battery (or power supply), perhaps with a switch somewhere in the loop. When it is switched on, there is an electric current flowing throughout the circuit instantly.

An electric current is a movement of tiny, charged particles. The wires and other devices in a circuit are made up of particles, including electrons which are negatively charged, and are free to move (please note the children do not need to know the term ‘electron’). These charges all move together (like a continuous belt, or chain). As they are negatively charged, electrons move away from the negative terminal of the battery and towards the positive terminal.

All materials are made from particles called atoms. Electrons are part of the structure of atoms. In some materials these electrons are free to move outside the structure of the atom. These materials are called conductors. If we connect a battery across a conductor the voltage in the battery makes the electrons move, causing an electric current to flow through the conductor. All metals are good conductors. Some other materials such as graphite are also conductors as they have electrons which are free to move.

In other materials, electrons are not free to move, and these are called insulators. Insulating materials have important safety uses in circuits and electrical appliances. Insulators include materials such as glass, plastics, wood and wool.

3. A simple circuit is a collection of components, connected in a loop of conducting material, with a power supply.

Pupils need to know:

• Many common electrical components (e.g. a bulb, motor, buzzer) have two connection points, or terminals.
• To operate such a component, its two terminals need to be connected by wires (or other conducting material) to the two terminals of a battery (or other power supply).
• Several components can be operated from a single battery by connecting them with wires in a closed loop from one battery terminal to the other.
• The order of the components round the loop makes no difference to how they work.
• We use symbols to represent different components when drawing scientific diagrams of circuits (circuit diagrams).

Background Science for Teachers

A complete circuit is needed for an electric current to flow. This means there is a complete loop without any gaps, through wires and components, from one terminal of a battery (power source) to its other terminal. If the battery and components are arranged in one single loop, we call this a series circuit. (Parallel circuits are only taught at secondary school.)

A drawing of a simple circuit and how this is portrayed through a Circuit diagram. 

Image credit: Amanda Poole. Licensed only for use on Explorify.

You can tell if a current is flowing in a circuit if a buzzer (attached the correct way round) makes a sound, a lamp lights, something gets hot or a motor moves. Motors can rotate clockwise or anticlockwise. To change the direction of rotation you can reverse the way the wires are connected. (Please note that if you are using LED bulbs they will only work if connected the correct way in a circuit.)

It is the voltage provided by the battery or power supply that pushes the negatively charged electrons around the circuit. We call the rate of flow of charge (such as electrons) – how many charges pass a point in one second –the electric current. In a series circuit, the electric current is always the same in every part of the circuit. Some children may believe the electric current is ‘used up’ by an electric bulb in a circuit, so there is less current ‘going back’ to the battery in the wire after it has lit up the electric bulb. The electric current in the wires on both sides of the bulb are the same. For more guidance about how to handle misconceptions read this PSTT guide.

Many devices are designed to be used with a battery (or power supply) that has a particular voltage; often this is marked on the device. If a device is connected to a battery of smaller voltage, it will not operate properly or not at all. A device can be damaged if it is connected to a battery whose voltage is higher than it is designed for (because it causes a current that is larger than the device is designed to take).

It’s very important to choose the correct batteries for circuit work. CLEAPSS recommend using zinc-carbon or zinc-chloride batteries in classroom circuits. This is because if a child creates a short-circuit by using one wire to connect the positive and negative terminals of a battery, the battery can overheat becoming hot enough to cause a burn, melt plastic holders and insulation, as well as vent hot fumes and corrosive chemicals.

Standard symbols are widely used to represent electric circuits.

Circuit symbols, explained. 

Image credit: Amanda Poole. Licensed only for use on Explorify.

The size of the current in a series circuit depends on the voltage of the battery (or power supply) and the components in the circuit. Increasing the battery voltage increases the current. Increasing the number of components decreases the current.

4. Switches are used to control simple circuits.

Pupils need to know:

• An electric circuit needs to be a closed loop to work
• Switches open and close a gap in a circuit.
• We can use switches to control whether a circuit is working or not.
• Components such as a lamp, buzzer or motor will work when a switch in the circuit is closed but will stop working when the switch is open.

Background Science for Teachers

There are different circuit symbols for an open and a closed switch.

The symbols for open and closed switches, supported by images of switches found in the home. 

Image credit: Amanda Poole. Licensed only for use on Explorify.

A switch is able to ‘make’ or ‘break’ an electrical circuit by either creating or closing a gap in the loop, so that an electric current can flow or stop flowing. A closed switch position is a conductor to close a gap in the circuit; an open switch creates a gap in the conducting loop.

There are different types of switches, such a push switches, toggle switches and rocker switches.

Pupils might think that in an open/incomplete circuit, the current flows to the part where there is a gap then ‘turns back’ to the battery when it finds that it cannot flow through the gap. In an open circuit, current does not flow at all. For more guidance about how to handle misconceptions read this PSTT guide.

5. Changing the voltage of a power supply affects components in a circuit.

Pupils need to know:

• Increasing the voltage across a lamp will make the bulb brighter and decreasing it will make it dimmer.
• Increasing the voltage across a buzzer will make the buzzer louder and decreasing it will make it quieter.
• Increasing the voltage across a motor will make it spin faster and decreasing it will make it slower.

Background Science for Teachers

When more batteries are added to the circuit there is a larger voltage across the components in a circuit. This causes a greater electric current to flow through it, which in turn affects the component, making lamps brighter, buzzers louder or motors faster. If several batteries are connected in line (in series), the voltage of the combination is the sum of the voltages of the individual batteries, taking account of their directions.

If you increase the voltage across a circuit component, the electric current flowing through it will increase.  

(These next 2 paragraphs talk about energy transfer which is not covered in the primary science curriculum. However, if you as a teacher are interested in understanding more about this challenging concept including the terminology of energy stores and energy carriers/pathways this article 'Helpful language for energy talk' from the Institute of Physics can help.) 

The larger the electric current flowing through a lamp the brighter it will be. The electric current transfers energy electrically from the chemical energy store in the batteries to the thermal energy store in the filament light. This thermal energy is then transferred by heating (through radiation (light) and particles) to the surroundings. The more batteries in series in a circuit, the more stored energy is transferred per second, so the brighter the lamp will be.

The greater the current flowing through a buzzer, the louder it will be. The electric current transfers energy electrically from the chemical energy store in the batteries to the kinetic (movement) energy store in the buzzer. This then uses sound (known as a mechanical energy pathway) to transfer energy to the surroundings. The more batteries in series in a circuit the more stored energy is transferred per second, so the louder the buzzer is.

Useful related resources    

   The Ogden Trust: Phizzi focus: Electricity

    This resource highlights the opportunities for pupils to make links between their science learning and the real world through problem solving and creative projects

Ideas to try with your class  

Now you've got the key scientific concepts under your belt, try our ideas to help you explore electricity with your class in a way they will understand in part two of this topic guide! 

You can also take a look at the related topic guides for light and forces. 

Many thanks to the Ogden Trust, who have collaborated with Explorify to produce this 'Tackle the tricky bits' page.

Image credit: UK British electrical plug socket and plug on a wall by lleerogers via Canva