We had to do a lab activity in chemistry today, and it involved putting a piece of foil (dull side up) in a beaker, a penny on top, and adding waterWe previously let it sit there for 48 hoursThe penny turned black underneath and the foil had wholes in it and turned a slight rusty color.Can someone please explain what chemically happened and what role the water, penny and foil played in the lab? I\'m really confusedThanks a lot!The aluminum reduced the oxide coating on the copper pennyThe aluminum, by reducing the copper oxide, became oxidizedThe aluminum lost electrons and the penny gained electrons It is kind of like the reaction in a battery.Other related question