"The use of radar in World War II... was a vital factor in the successful defense of Great Britain"
R. Hanbury Brown, Robert Watson-Watt, physicists
In 1935, with hostilities looming in Europe, the British government asked Scottish physicist Robert Watson- Watt (1892-1973) to develop a personnel-destroying "death ray" that could harm the opposition. Watson- Watt demonstrated that this was an impossible ambition. However, he theorized that a radio wave could be sent to bounce against a moving object, and monitoring its travel could then provide information about the target, such as its speed, direction of travel, and altitude. This could also determine the distance from the transmitter of fixed objects. A demonstration won favor with the government, and Watson-Watt subsequently gave the technology the name radar (radio detection and ranging).
By the beginning of World War II, Watson-Watt had installed a chain of radar stations across the United Kingdom, and two other British physicists, Henry Boot and John T. Randall, developed his concept of the resonant-cavity magnetron. This electron tube was capable of generating high-frequency radio pulses with huge amounts of power. This in turn led to microwave radar, which is now used to measure atmospheric pollution and, more importantly, in modern forms of communications.
