Potato Battery

Do you think you can use a potato to power a clock? Check out this experiment!

The Experiment

This experiment is based on a similar experiment from PBS Kids.

Materials:

A medium or large potato
A plate or newspaper
2 galvanized nails
2 pennies
3 pieces of copper wire

a digital clock

Try it out:

1. Cut the potato in half and place the two pieces on the plate or newspaper
2. Put a nail into each potato half. Wrap a piece of copper wire around one nail.
3. Wrap each penny with a piece of copper wire and stick the pennies inside the potatoes (at the opposite end from the nail)
4. Connect the wire from the penny on the first potato half to the nail without any wires on it in the second half.
5. Connect the remaining two ends of wire to the + and - ends of the battery compartment of your clock. If the clock doesn't work, try switching which end you connect the wires to.

What's happening

When you connect the potato to the nails (zinc) and the pennies (copper), you make an electrochemical cell. This means you are turning chemical energy into electrical energy.

So how does that work? All atoms are made up of a nucleus surrounded by electrons.

When the zinc and the copper are near each other, they start to react. The zinc atoms pass some of their electrons to the copper atoms. This is a simplified reaction:

As the atoms keep on passing electrons to each other, a current is formed in the copper wires. This current is what powers your clock!

If you thought this was cool...

This experiment is related to electrical engineering. You can find out more here.
You'll learn more about the reaction that creates the electric current when you learn about redox reactions in chemistry.