Wireless works because an electromagnetic wave, passing through the air at the speed of light, can create - or 'induce' - an electrical signal in an aerial....
When scientists first realised that electromagnetic waves could be transmitted through the air, they didn't understand the full extent or impact of what they'd discovered....
Although you can communicate over long distances with wireless, there are limits because the Earth's surface is curved and electromagnetic waves may be lost before reaching their intended destination....
Mobiles phones have changed our lives since the first ones appeared in 1985. Today's mobile phones are triumphs of miniaturisation - there's nothing else you own that's likely to fit so much technology into such a small package....
