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🧪 Science ⚡ Energy and electricity

Battery

Batteries have many uses. The small button battery at the front powers a wristwatch. The big battery at the back gives a car the power it needs to start.
Batteries have many uses. The small button battery at the front powers a wristwatch. The big battery at the back gives a car the power it needs to start.

📖 In short

A battery is a small box that makes electricity from chemicals inside it. Thanks to batteries, toys, watches, flashlights, remote controls and phones work without being plugged into a socket.

🤩 Did you know?

  • A small flashlight battery has a voltage of 1.5 volts.
  • The Italian scientist Volta invented the first battery more than 200 years ago, and the “volt” unit is named after him.
  • Some huge submarine batteries weigh about a tonne.
  • Small round button batteries are very dangerous if a child swallows them.

🔎 Find out more

🌟 How does it work?

Inside a battery are two different chemicals with a substance between them. When the two ends of the battery are connected to a device, the chemicals slowly react, and electricity flows from one end to the other through the device, making it work.

🔍 Positive and negative

Every battery has two ends: positive, marked “+”, and negative, marked “-”. We must put the battery in the device the right way round for it to work.

💡 Rechargeable batteries

Some batteries are used once, and some can be recharged many times, like phone and electric car batteries.

🎯 Careful!

Don't open a battery, put it in your mouth, or throw it in a fire or the ordinary bin, because its chemicals can be harmful. Put old batteries in special bins for recycling.

📸 More pictures

A dry cell is made of a zinc case filled with substances that produce an electric current through a chemical reaction. The wall of the case itself is the cell's negative terminal. The carbon rod in the middle is the positive terminal.
A dry cell is made of a zinc case filled with substances that produce an electric current through a chemical reaction. The wall of the case itself is the cell's negative terminal. The carbon rod in the middle is the positive terminal.
A 9-volt battery is made of six dry cells, each producing 1.5 volts. The cells are connected one after another so the total voltage is 9 volts. Batteries like this power transistor radios.
A 9-volt battery is made of six dry cells, each producing 1.5 volts. The cells are connected one after another so the total voltage is 9 volts. Batteries like this power transistor radios.
Parts of a lead-acid storage battery: most lead-acid batteries have six cells, each containing two sets of lead electrodes called plates. The plates are separated from each other by sheets of plastic or rubber. A solution of sulfuric acid, called…
Parts of a lead-acid storage battery: most lead-acid batteries have six cells, each containing two sets of lead electrodes called plates. The plates are separated from each other by sheets of plastic or rubber. A solution of sulfuric acid, called…

🧩 Test yourself

1 What does a battery make electricity from?

2 Where do we put old batteries?

3 The Italian scientist Volta invented the first battery more than ?? years ago, and the “volt” unit is named after him.

4 Which picture shows “Battery”?

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