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.

Introduction

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.

Materials

  • 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

Steps

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
setup

Troubleshooting

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

To unlock this lesson you must be a Study.com Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use Study.com

Become a Study.com member and start learning now.
Become a Member  Back
What teachers are saying about Study.com
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create An Account
Support