David's Green Science

My nephew, David, is 4 years old. He and my brother powered a clock using an apple, two wires connected to the clock and two electrodes. The clock was still working 24 hours later and showed the correct time. The electrodes in the potato battery kit can be replaced by other metals such as a nail and a coin. That's right! There is a kit for kids for building this type of battery for potatoes, but it works with most other fruits and vegetables.

Warning: The apples should not be eaten after they are used in this type of battery. They will contain zinc, which is toxic.

How does it work?  The zinc ions and copper ions are separated by the apple. Otherwise they would interact with each other and produce a little bit of heat. The electron transfer takes place over the copper wire, which powers our clock. Chemical energy is converted into electric energy by electron transfer. The electricity produced is not much (definitely not enough for a person to feel), but clocks need very little energy to run and this makes them ideal for this project.