When was Television invented? John L. Baird of Scotland made the first simple television soon after the first world war. Public TV started in 1936 in Britain.   How does a television camera work ? A TV camera has to convert a whole picture into an electric current. First of all a picture, called an ‘image’, of the scene in front of the camera is focused onto a screen inside. A...

What are Radio Waves?   Radio waves are like light except that we cannot see them with our eyes and they are harder to stop. They can go through walls, for example. In fact, light and radio waves are both examples of ‘electromagnetic radiation’. Like light, radio waves travel 300,000 km (I 86,000 miles) each second and go in straight lines unless blocked (by something like thick concrete) or reflected. Because...

How are Radio messages sent and received? The sender speaks into a microphone which converts the sound of his voice into an electric current. A transmitter first makes this current stronger then feeds it to an aerial which sends out radio waves. This aerial is a long wire, often as tall as a high building. When radio waves hit another aerial, like the one on your radio set, they are picked...

Who invented Radio? An Italian, Guglielmo Marconi, made the first proper radio. In 1901 he sent the first message right across the Atlantic Ocean. Nowadays radio stations transmit the programmes we listen to at home. Other uses include communication with ships, aircraft and spacecraft ; sending messages between police; and controlling taxicabs.

Achievements of the Elizabethan Age    Elizabeth I gave England the strong government which it had lacked since the death of her father, Henry VIII, in 1547. Her policy was marked by moderation and caution in all things. By firmly establishing the Church of England, with herself at its head, she found a  solution to the religious problem which  satisfied the majority of her subjects. In her relations with foreign countries...

Why is Elizabeth I remembered as a Great Queen?   During her short five-year reign, Queen Mary Tudor had become much disliked because of her religious views, her marriage with Philip of Spain who was a  Catholic , and her disastrous war against France, which resulted in the loss of Calais, England’s last French possession. Therefore when Mary died in November 1558 and was succeeded as queen by Elizabeth, there was...

Why do cuckoos have foster parents? Because cuckoos breed parasitically ! That is, the cuckoo hen places her egg in the nest of another bird and leaves it to hatch and be fed and nourished by a foster mother, so forcing her young to live on the hospitality of a different species. Each cuckoo hen confines her breeding activities to a particular territory, and after having mated, spends much of her...

Why do birds migrate and how do they find their way? Many species of birds migrate in winter to a warmer climate, but it is puzzling as to exactly how they find their way ! Many birds follow coastlines and are able to recognise landmarks, for they have good eyesight. Scientists believe that some birds such as pigeons, gulls and the Manx shearwater use the sun or the stars as a...