When I went to Mind Lab with the Science Discovery group I learned that you could make electricity with a chemical reaction.  The copper wire was the positive and the nail was the negative.  We put water and table salt into a little cup and put the copper wire and nail into it.  Then we measured the electricity and it was 0.75 volts.  We made four power cells and it measured 3 volts.  We powered an LED light with the power cells.

By Tony