http://www.apple.com/batteries/
This week in class we learned that voltage is a field surrounding charged objects and electric potential energy is Ue=charge(voltage). Voltage is like a mountain or altitude(or like the "gh" in Ug=mgh). We were able to make a battery out of a lemon because its acidic nature is like the acidic solution in regular batteries and we also stuck a penny(- charge) and a nail(+ charge) into opposite sides to conduct electrons. This is relevant to the world today because the battery has not changed much since it was first invented. Our lemon battery didn't have very much voltage but it can be compared to the iPad battery because they both have the same basic science behind them. I went to the apple website to find more information about the batteries. The batteries that power our iPads are lithium-ion polymer. I learned that they are designed to work in a certain charge cycle to maximize the battery life. They have a high-power density but it is very light. These special charge stages have to do with voltage and charge current, which is described in this chart:
