Alexander Graham Bell was interested in the troubles of deaf peoples-people who can’t hear. Both of his father and his grandfather had spent their lives studying human speech and teaching the deaf to speak. Just a few years before he invented the telephone, Alexander opened a school for teachers of the deaf.
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Alexander Graham Bell was also interested in electricity. He experimented with things he hoped might help the deaf to hear. These experiments gave him the idea for the telephone.
In his invention a sound-such as a person speaking-made a thin circle of metal vibrate, or move back and forth very fast. The vibrating part changed the way electricity moved through the wires from one phone to another. A loud sound sent more electricity through the wires than a soft sound.
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These electric changes made a part in the listener’s phone vibrate, which created a sound very much like the sound the speaker made into his phone. That’s pretty much how the telephone still works today. To the person listening, it seems as though the sound is coming through the wire. But it isn’t- only electricity is! The electricity is changed back into sound inside the listener’s telephone.
When someone invents something, that is only the beginning. Men all over the world immediately look for ways to make the invention work better. That is exactly what happened with the telephone.
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If Mr. Bell were alive today, he would probably surprised and pleased to see how his telephone has been improved. Now telephone calls can be made to millions of people all over the world. On some calls the message goes through wires inside huge cables stretched across the ocean bottom. On other calls the message is sent by radio and bounced off communications satellites high above the Earth.
