Make a Lemon Battery

Did you know that you can make batteries using certain fruit and vegetables?! Let's make a lemon battery strong enough to power an LED (light emitting diode).

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things you will need

  • 4 zinc (galvanised) covered nails
  • 4 x 2cm copper wires (or clean pennies)
  • 5 croc clip leads
  • 4 lemons (or two cut into four)
  • 1 x LED (light emitting diode)
  • Sandpaper

safety notice

  • You will need to throw the lemons away after using them in this experiment.
1

Clean the metal

Use the sandpaper to gently clean the nails and copper wire (or pennies).

2

Prepare your batteries

  • To create a battery we need a positive electrode, a negative electrode, and an electrolyte.
  • Give each lemon a rub to help release the electrolytes.
  • Push a copper wire or penny into one end of each lemon. The copper wire will be the positive electrode.
  • Push a nail into the other end of each lemon. The nail will be the negative electrode. 

Things to know

An electrode is a wire that is used to make contact with a non-metallic substance. An electrolyte is a non-metallic substance that can gain or release electrons.

3

Line 'em up

  • Set up the 4 lemon batteries in a row.
  • Connect a red croc clip lead to the copper wire (or penny) in the first lemon.
  • Connect a black croc clip lead to the nail in the last lemon.
4

Connect the batteries

  • Using the remaining croc clips connect the zinc nail in lemon 1 to the copper wire (or penny) in lemon 2.
  • Repeat until all lemons are connected.

Things to know

The chemical reactions between the lemon juice, nails and wires (pennies) has already begun. 

Electrons are leaving the copper wires and are building up on the nails. The extra electrons on the nails want to hop over to the copper wires but the lemon juice keeps pushing the electrons the other way. 

5

Connect the LED

  • Let’s see what happens when you connect an LED.
  • Connect the red croc clip connected to the first lemon to the long leg of the LED.
  • Connect the black croc clip connected to the last lemon to the short leg of the LED.
6

What's happening?

You should now be able to see light but what’s happening?

Electrons will always find the easiest path to close the loop. In this case, the easiest path for the extra electrons on the nail is through the LED and into the copper wire.

Try repeating the experiment with different fruits and vegetables. Is the LED brighter or dimmer?

 

Top tip

Head to a dark room to check whether your lemon batteries are working and your LED is ON.

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