How the battery works

The idea behind a battery is very simple. It is the idea that electricity will flow between two different metals if they are placed against each other. It is very easy to test this idea. Take a clean penny and a clean dime. To make sure they are clean, wash them first with hot water. Lay the two coins against each other. Holding them between your fingers, place the tip of your tongue against the two edges. It will taste very bitter. The bitter taste is the electricity flowing between the penny and the dime. Volta did not think of this idea by himself.

He got the idea from another Italian named Luigi Galvani. Galvani did an experiment with a freshly killed frog. He connected a piece of zinc and a piece of copper to the ends of a wire, then touched the frog's leg with the wire. He was very surprised when the leg snapped back. Since the frog was dead, Galvani could not explain why its leg had moved. Volta explained that electricity had made the frog's leg move. This electricity passed from the zinc through the wire to the copper and through the frog's body.

The frog's leg had jumped for the same reason we jump when we receive an electric shock. From this idea, Volta was able to make the first battery. He lined up some discs of zinc and copper. He placed a piece of cloth soaked in sulfuric acid (which is a good conductor of electricity) between zinc and copper discs. He did this until he had a line of many zinc and copper discs, all separated by pieces of cloth soaked in sulfuric acid. He then attached a wire at one end of his battery to the zinc disc and another wire at the other end to the copper disc. When he touched the two wires together a red spark jumped between them. This spark showed him that electricity was flowing through the wires from the battery.