Potato Light Bulb Experiment

Instructor: Amanda Robb
In this project, you'll be using the natural chemicals inside a potato to light a light bulb. By completing this project, you'll learn about chemical reactions inside batteries and ways to create natural sources of electricity.


Goal: To light a light bulb using a potato
Age: Middle school and up
Safety concerns: We will use a knife to cut the potatoes. Use caution and have an adult help you.
Time: 1 hour

Right now you're probably using your laptop or phone to learn about this chemistry project. Both of these devices can work without be plugged in because they are equipped with batteries. Batteries are chemical cells that convert chemical energy into electrical energy. If you need a refresher on how batteries work, check out this lesson on battery basics: How Does a Battery Work? - Lesson for Kids

Although we usually think of batteries as being made of metal, today we're going to see if we can use the chemical energy in potatoes, a vegetable, to power a light bulb. Before you start, think about what's inside the potato that might help light the light bulb.


  • 2 large russett potatoes
  • Two 2'' pieces of thick copper wire
  • Three 4'' pieces of thin copper wire
  • Two galvanized nails (nails covered in zinc)
  • 6 alligator clips
  • Small knife
  • 1.5 volt light bulb


Safety Tip!! Use caution when handling the knife and get an adult to help you if needed.

  1. First, make two slits about 1'' deep on each end of each potato.
  2. Next, insert the thick copper wire into one slit and the nail into the other slit. Do this for both potatoes.
  3. Connect the alligator clips to each end of the three pieces of thin copper wire.
  4. Connect one alligator clip on the first piece of wire to the heavy copper wire in the first potato, and attach the other clip to one end of the light bulb.
  5. Then, attach one alligator clip on the second piece of wire to the other end of the light bulb, and attach the other clip to the nail on the second potato.
  6. Finally, attach one alligator clip on the last piece of wire to the thick copper wire on the second potato, and attach the other clip to the nail on the first potato.
  7. Observe what happens to the light bulb.

Experiment setup


Make sure all your wires are securely connected to the alligator clips and then to the metal. If the circuit isn't tightly wired, the electricity can escape. The metal in the potatoes must be copper and a nail covered in zinc. A steel nail will not work and other wire won't conduct electricity as well.

Discussion Questions

What happened when you completed the circuit?

What do you think would happen if we added more potatoes to the circuit?

How It Works

Before we explain how the potato acts as a battery, let's go over the parts of a regular battery you might find in your television remote. Batteries are made of three main parts: an anode, a cathode and an electrolyte.

Parts of a battery
battery diagram

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