Skip to content

Batteries

Electricity and magnetism · level 1, lesson 4 of 6

A question to start

A torch, a toy car and a TV remote all stop working one day, until you put in new batteries. What is inside a battery?

The idea

A battery stores energy, and it can push electricity round a loop of wire. That makes bulbs glow, motors spin and speakers play.

  • Every battery has two ends: plus (+) and minus (−). They must go in the right way round.
  • Inside, there are chemicals. As the battery is used, they change, until the battery is flat.
  • Some batteries can be charged again, like the one in a phone.

Small batteries are safe to play with. The sockets in the wall are not: never put anything into them.

+− a battery stores energy

Worked examples

1. The right way round. In a torch, the + end of each battery points the same way as the + mark in the case. Put one in backwards and the torch stays dark.

2. A flat battery. A toy car gets slower and slower, then stops. Its batteries are flat: their chemicals are used up.

3. Charging. A phone plugged in at night is filling its battery with energy again.

Try it

  1. What does a battery store?
  2. What are the two ends of a battery called?
  3. What does it mean when a battery is flat?
  4. Name something in your home with a battery you can charge again.
Answers
  1. Energy.
  2. Plus (+) and minus (−).
  3. Its chemicals are used up, so it can no longer push electricity.
  4. Any one: a phone, a tablet, a laptop, an electric toothbrush.

Common mistake

"A battery is full of electricity." It is full of chemicals that store energy. The electricity only flows when the battery is joined into a loop.

Where it leads