BATTERIES
When you look at it a battery is simply a bunch of chemicals put in a can to produce electrons. All batteries have two terminals, a positive and a negative, weather it be a truck battery or a cell phone battery. When a battery is not connected to anything electrons build up at the negative terminal. But to create more electrons the electrons must travel through a load (something like a light bulb) and to the positive terminal, this creates a chemical reaction that creates more electrons. This will continue until the chemicals burn out.
