Long distance communication
People have always needed to communicate with each other. If people are close enough to see and hear each other they can talk. If they are for apart it is more difficult. The way we communicate over distance is changing all the time.
Two hundred years ago, if you wanted to communicate with someone for away you had to send a letter. It could take months.
One hundred years ago, you could talk to someone hundreds of miles away by telephone. Alexander Graham Bell was a teacher of deaf children. He worked out how electricity could carry the human voice. In 1876, Bell invented the telephone. People could now talk directly to each other, even if they were some distance apart.
Today, we can communicate with people all over the world in lots of different ways. We can talk on mobile phones, send faxes, read texts messages and send emails. As well as using word, we can send moving pictures, sounds and music.