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How to Build a Lemon Battery
Creating a battery from a lemon is a common project in many science text books. Successfully creating one of these devices is not
easy.
Batteries consist of two different metals suspended in an acidic solution. Copper and Zinc work well as the metals and the citric acid
content of a lemon will provide the acidic solution. Batteries like this will not be able to run a motor or energize most light bulbs. It
is possible to produce a dim glow from an LED.
The picture at the top of this page shows a basic lemon battery, a lemon, copper penny and zinc coated nail.
Materials: One lemon: A large, fresh, "juicy" lemon works best.
One nail: Galvanized nails are coated in zinc. I used a 2" galvanized common nail.
One penny: Any copper coin will work. (Canadian pennies from 1960 - 2001 all worked, but – older pennies contain more copper
Creating the battery: Insert a penny into a cut on one side of the lemon. Push a galvanized nail into the other side of the lemon.
The nail and penny must not touch.
This is a single cell of a battery. The zinc nail and the copper penny are called electrodes. The lemon juice is called electrolyte.
All batteries have a "+" and "-" terminal. Electric current is a flow of atomic particles called electrons. Certain materials ,
called conductors, allow electrons to flow through them. Most metals (copper, iron) are good conductors of electricity. Electrons
will flow from the "-" electrode of a battery, through a conductor, towards the "+" electrode of a battery. Volts (voltage) is a
measure of the force moving the electrons.
How to Make a Potato Powered Light Bulb
Mad Science Resources
Did you know you could power a light bulb with a potato? The chemical reactions that take place between two
dissimilar metals and the juices in the potato create a small amount of voltage that can power a very small electrical
device. Follow the instructions below to make a potato-powered light bulb.
Materials:
 A large potato
 Two pennies
 Two zinc-plated nails
 Three pieces of copper wire
 A very small light bulb or LED light
Procedure: What you need to do:
1.
2.
3.
4.
1. Cut the potato in half, then cut a small slit into each half, large enough to slide a penny inside.
Wrap some copper wire around each penny a few times. Use a different piece of wire for each penny.
Stick the pennies in the slits you cut into the potato halves.
Wrap some of the third copper wire around one of the zinc-plated nails and stick the nail into one of the potato
halves.
5. Take the wire connected to the penny in the half of potato with the nail and wrap some of it around the second
nail. Stick that second nail into the other potato half.
6. When you connect the two loose ends of the copper wires to the light bulb or LED it will light up
[source: MathinScience].
7. Be careful when handling the wires, because there is a small electric charge running through the wires.
Hydrogen gas may also be a byproduct of the chemical reactions in the potato, so don't perform the
experiment near open flames or strong sources of heat.
Options:
Potato battery varieties:
Yes, you can compare/contrast the strength of two potato batteries made from slightly different sizes of the
same type of potato. Or take two varieties of potatoes (about the same size) and compare/contrast their
power.
Experiments with other types of fruit or vegetables:
With galvanized nails, copper wire, and pennies, you can experiment with making a variety of batteries that
will produce enough electricity to power simple led devices. Some of the photos shown below include
some hidden wooden toothpicks that acted as non-conductive props to hold up wires, etc.