Q. Why does a cell phone have to be charged?

A. When we use a cell phone, it produces a call signal, musical tones and lights up. A phone's batteries store an electrical charge that it can use. If we talk a long time on the phone or listen to music, the batteries may become so depleted that we can no longer use the phone. You will find a battery not only in your cell phone but also in a portable radio, CD player, flashlight or video camera. There are disposable batteries and rechargeable batteries, such as those in cell phones. Electrons produced by a chemical reaction flow through whatever is connected to the battery from the battery's negative terminal to its positive terminal. Rechargeable batteries can restore their electrical charge if connected to an external electrical source (recharger). It's like when we are hungry and have little energy to move at all; once we have something to eat, we are ready to move on.