Electricity travels through circuits made of ions. These ions come from many sources; salt, minerals, several kinds of metal and acid. Humans take advantage of these conductive materials to power machines through batteries. Most batteries are simple metal tubes filled with powerful acid. They complete an electrical circuit inside machines and make them work. You can create your own battery at home with items from your refrigerator. Many fruits and vegetables contain the acid necessary to conduct electricity. Simple experiments include using produce to light a light bulb. This experiment is simple and entertaining, and has several variations.
Push one copper rod and one steel rod into each fruit or vegetable you plan to test. The rods should stick straight up and be as close to the ends of the produce pieces as possible. The rods should slide about halfway into the produce.
Clip one alligator clip wire to each copper and steel rod. The other ends of the wires should hang loose.
Place the other end of each alligator clip wire on one piece of produce on the light bulb holder's metal clips; the light bulb should light. A light bulb holder is a small, black plastic pedestal that holds a single, low-watt light bulb with clips on either side of the bulb for wires.
Test each fruit or vegetable as you did in Step 3 by removing the clips of one piece of produce and replacing them with another. Record which pieces light the bulb and which do not. This shows which ones have the right amount of acid.
Use two pieces of produce at once by clipping an alligator clip wire between the copper rod of one piece and the steel rod of another. Clip more wires between the free rods on each piece and the light bulb holder. If the light bulb doesn't light, replace one of the produce pieces until it does.
Never eat produce used to conduct electricity. Minerals from the metal can leach into the fruit and make it toxic.