Grade 4 · Unit 5: Electricity and magnetism

Electricity flows in circuits

Electricity needs a complete loop to flow.

Build circuits and watch the current flow in the Circuit Builder lab.

A loop for electricity

Electricity flows around a circuit. A circuit must be a complete loop, with no gaps. The flow of electricity is called the current.

Scientists draw the current flowing from the + end of the cell, round the circuit, to the – end.

The cell pushes

A cell pushes the current around the circuit. The current leaves one end of the cell, goes round the circuit and comes back to the other end. When the cell runs out of energy, the current stops.

A cell stores chemical energy. When the circuit is complete, a chemical reaction inside the cell pushes the current round.

Breaking the loop

If there is a gap anywhere in the circuit, the current stops. All the bulbs and motors in that loop stop working. A loose wire or a broken bulb can make a gap.

Fairy lights on one loop all go out if one bulb breaks. Newer sets are wired so that the others stay on.

Electricity in the body?

Even your body uses electricity! Nerves send tiny electrical messages between your brain and your muscles.

Doctors can measure the tiny electrical signals from your heart with a machine called an ECG.

What I learnt