How to Make a Potato Clock for a Science Fair Project

A potato can function as an electrochemical battery.

Using a potato to generate the energy necessary to run a small clock is a classic science fair project not only because it is impressive, but because it is also impressively simple to pull off. The experiment works by conducting the energy created in a chemical reaction between two types of metal meeting in potatoes to the battery compartment of a small clock. You may find it necessary to adjust the wire connections if your potato clock does not immediately work.

Things You'll Need

• Two potatoes
• Two short pieces of copper wire
• Two galvanized nails
• Three alligator clamps connected by wire
• Small digital clock
• Marker

Instructions

1. Label the potatoes "1" and "2." Drive a nail partially into the end of each potato. Carefully push a piece of copper wire into each potato as far as possible from where you inserted the nail. Both potatoes should have a copper wire and a galvanized nail protruding from opposite ends.

2. Remove the battery from the clock and use the marker to indicate where both the positive and negative terminals of the battery were connected.

3. Connect one end of one of the alligator-clipped wires to the positive terminal of the clock. Clamp the other end of the wire to the copper wire on potato 1. Use a second set of alligator clamp wires to connect the clock's negative terminal and the nail of potato 2.

4. Connect the final alligator clamp set to the nail of potato 1 and the copper wire of potato 2. This should complete the circuit and begin supplying a small amount of electricity to the clock.

References

• Kidz World: Potato Battery

Resources

• Read this Article in Spanish