Up next in How to Do Fun Tech & Science Projects (52 videos)
School science fair coming up? Don't worry: We've got step-by-step instructions to dozens of science projects in this Howcast video series, including how to build an erupting volcano, how to make glow-in-the-dark art, how to make a weather barometer, how to make disappearing ink, how to make 3-D glasses, and how to make a marshmallow gun.
You Will Need
- A knife
- 4 lemons
- 4 pieces of copper wire
- 4 galvanized nails
- 5 jumper wires
- An LED light
- Four U.S. pennies minted before 1982 or four Canadian pennies from before 2001 (optional)
Soften the lemon
Roll a lemon around on a table to soften up the inside without breaking the skin. If it's too firm, it could reduce the battery's charge.
Put the copper in
Use the knife to cut a slit in one lemon and insert the wire so a bit of it sticks out. This is your battery's positive terminal.
Put the nail in
To make the negative terminal, push the nail into the lemon about 2 inches from the penny. Leave a little of the nail exposed above the skin. Make sure the copper and nail are not touching, or it will cause a short.
Measure the current
Turn on the voltmeter. Touch the positive lead to the penny, and the negative lead to the nail. If the meter indicates that the lemon is creating a little less than one volt or more, you've successfully made a battery.
Make more batteries
Make three more lemon batteries. A single lemon won't produce enough electricity to light the bulb.
Connect the batteries
Clip the first jumper wire to the nail in the first battery, then run the second wire from the penny of the first lemon to the nail in the second lemon. Then connect the penny in the second lemon to the nail in the third, and the penny in the third to the nail in the fourth.
Light the bulb
Light the LED by connecting the first jumper wire from the nail to the negative connection on the LED. The negative connection is the wire nearest the flat spot at the base of the light. Then clip a jumper wire from the penny of the last lemon in your chain to the positive connection on the LED and presto! Lemon-powered light!