The next day, the teacher brings in an old telephone receiver which she takes apart to help provide a more visual reference. The students all agree that what goes into the mouth-piece is sound energy (or sound waves), but that which passes through the wire is electricity (or some type of electric signal). The question: How to explain the electrical signal that passes through the phone line when that which goes in is sound energy? After several moments of silence, blank stares, half-hearted attempts at answering, and puzzled expressions, one student offered that some type of spare must be responsible for the sound energy becoming electrical signals. Bingo! Sound energy converted into electrical signals which are then converted back to sound energy on arrival at the receiving end! Then one of the students asks: What does this have to do with American History? Another student responds: If Mr. Bell had not attempted to find out how to make sound pass through a telephone wire we would not be studying him.
[Photographic Art by Ric Couchman]