Talking with electricity
Alexander Graham Bell understood the theory of a telephone, but struggled for a number of year to make a working model. Then, on March 10th 1876, he finally succeeded in transmitting speech. Bell's first telephone did not resemble the telephones of today, and over the next 100 years it underwent many changes. A microphone was added to produce a stronger signal. Then, the telephone 'bell' was attached, and users were given a unique 'telephone number'. Once amplifiers were added in the late 1920s, a telephone system was established that allowed people to talk across continents- the era of long- distance phone calls had arrived.
50 years of progress
The first half of the 20th century saw enormous technical developments in three main areas: radio, telephone , and computers. Radio waves were the first to be explored, and in 1902, Marconi sent the first transatlantic radio signal. The first domestic radio with turners to listen to different stations appeared only 14 year later, in 1916. Once radio was established, scientists and inventors started investigating the possibility of transmitting pictures. The leap from transmitting sound to broadcasting pictures took place in 1925, when John Logie Baird sent the first experimental television signal. By 1939, regular scheduled television broadcasting had begun.
Computers were begin developed at the same time as TV and radio, and in 1944, computers were put into public service for the first time. The first generation of modern programmed electronic computers were built in 1947 and used Random Access Memory (RAM). This is a 'memory' which allowed access to any particular piece of information at almost any time. The smallest of these computers was the size of a family car and could store only about 8000 words. Since they were so large and stored so little, computers had to change considerably to become as widespread as televisions and radio had.