Ssince we see them all around us this is a good way to tie in the world around us to science facts. Starting with the basics of the properties of sound waves and how they are recieved, then going into the history of cell phone technology showing how it has gone from a complex radio to the Satellite Phones avalible today, then to sites showing how the signals are transfered from tower to tower and diagrams and photos of the insides of a cell phone.