††Radar is short for Radio Detecting And Ranging. It is a system of bouncing radio waves off an object, and timing the return to calculate how far away the object is. Although inventors such as Guglielmo Marconi and Heinrich Hertz had carried out numerous experiments with radio waves, no-one had attempted to use them to detect aircraft. During the 1930s the threat of war encouraged further experiments. In 1935 R.A. Watson-Watt was asked by the British government to develop a means of using radio waves to produce a kind of "death ray". Having explained that this could not be done, he suggested that he develop a method of aircraft detection. The first successful demonstration took place on 26th February, 1935. During World War 2 this system gave early warning of bombing attacks, which allowed defending aircraft to take to the air.
