Introduction: Lemon Batteries: Lighting an LED With Lemons

Did you know you can light an LED using fruits and vegetables?

For this experiment, you will need the following materials:

  • 4 lemons or potatoes
  • 4 galvanized nails
  • 4 U. S. copper pennies (minted before 1982 due to the change in copper content) or 4 copper wires
  • an LED light
  • a knife
  • 5 alligator test leads

Step 1: Creating the Batteries

  1. Using the knife, slice a penny-sized slit on the right side of your lemon.
  2. Push the penny far into the lemon, leaving a small area to hook your alligator jumper to. This will be your positive terminal.
  3. Now, create the negative terminal for your battery. Stick one of the galvanized nails into the left side of the lemon, about 2 inches away from the penny. It is important to have the nail and penny separated. If they touch, it will cause a short.
  4. Repeat this process until you have 4 complete batteries.

Step 2: Adding the Jumpers

  1. Make sure the lemons are aligned parallel to one another.
  2. Attach one of the alligator clips to the nail (negative terminal) on your first lemon.
  3. Then, run the second jumper wire from the penny (positive terminal) of the first lemon to the nail (negative terminal) in the second lemon. Add the rest of the clips, alternating positive an negative, until all the lemons are attached.

Step 3: Lighting the LED

  1. Connect the first jumper wire from the nail to the negative connection on the LED. The negative connection on the LED is the shorter wire nearest the base.
  2. Then, clip the jumper wire from the penny of the last lemon in your chain to the positive connection on the LED. When you complete your circuit, the LED will light up!
  3. Experiment with different fruits and vegetables to see which one produce the most volts! The higher the voltage, the brighter the light. The average lemon produces just under 1 volt. We need at least 3.5 volts to light up an LED. This is why we need 4 lemon batteries.