In march 10, 1876, Alexander Graham Bell first presented a working telephone. The first sentence spoken on telephone was: "Mr. Watson, come here; I want to see you", to which Mr. (Thomas) Watson, listening in the adjacent room, responded by coming over. Shall we say, small words (and steps) for two men, a great step for human technology?
However, Bell wasn't the first - or at least, not the only one - to invent a telephone. Elisha Gray had a similar invention at the same time, and both inventors filed for a patent on the very same day - but Bell managed to precede by a few hours.
Why not let the kids experience with their own "telephone"?
This old trick still works (behold, physics hasn't changed!):
Take two small plastic containers, make a small hole at the bottom of each, and thread a string between the two containers. Two people can use one such instrument, but it's best to have two - thus, each can hold one container as a mouthpiece and another as an earpiece. Either way, try to see what this telephone requires in order to work. Does it always work? If not, try stepping a bit further away from each other. Hmmm... Why does it only work when the string is fully stretched?
You can try this with different kinds of strings, and begin to sense the explanation: when the string is streched, the sound makes it vibrate. This vibration carries the sound waves to the other side, allowing the participants to hear and be heard. Some strings will work better than others. Why don't you experiment with it for awhile?
While we're at it, why not try to make your own microphone?
Lets' go back to Bell and his patent-war: surprisingly, winning the race to file the patent was not the last move in this saga. two centuries (!) later - in 2002 - the U.S. congress proclaimed the Italian Antonio Meucci - long dead, of course - inventor of the telephone. Meucci himself sued Bell at the time, but died during the legal procedure. The wheels of justice grind slow, it has already been said.
