Tick, Tock, Potato Clock
There are lots that can be done with a potato. From soup to french fries to hashbrowns, potatoes are a delicious food source that can be used in multiple ways. But did you know that these tubers can also produce power? Try out this experiment to get an idea of how batteries work and test out how chemical energy is turned into electrical energy.
- 2 large russet potatoes
- 1 knife
- 3 pieces of copper wire
- Alligator clips
- 2 galvanized nails (nails coated in zinc)
- 1 2V digital clock with the battery removed
- Ask an adult for help with this step. Have an adult cut a slit into each potato. Then, insert a copper wire into each of the slits.
- Now insert the nails, one into each potato, on the ends opposite the wires. Push them in about 1 inch deep.
- Open up the battery compartment of the clock and remove the battery if needed. Leave the compartment open for access.
- Using alligator clips, connect the wire from one potato to the positive terminal in the clock’s battery compartment.
- Again, with alligator clips, connect a wire from the nail in the other potato to the negative terminal in the clock.
- Lastly, connect the nail on the first potato to the copper wire on the second potato. Refer to the diagram to see what the set up looks like.
- What happens to the clock? The potatoes will produce enough energy to power the digital display!
- Note: Don’t eat the potatoes following the experiment – place them in the trash.
In a battery, two metals, such as zinc and copper, react with a solution to create an electric current. In a potato battery, the phosphoric acid in the potato juice reacts with zinc and copper. When the zinc nail is inserted into the potato, it comes into contact with the acid and loses electrons in the reaction. These electrons are picked up by the copper in the potato. These flowing electrons create an electrical current. Viola! You now have a potato clock!
Expand on this experiment by using a third potato. Do three potatoes power the clock longer? Why might that happen? What happens if you boil the potatoes ahead of time? Try slices or halves of potatoes versus whole potatoes. Document your findings to discover different configurations for true potato power!