Edith Strong, age 13, of Columbus, Ohio, for her question:
WHEN WAS RADAR DEVELOPED?
Radar developed only after many years of research in physics and radio. Physicists and mathematicians made many of the most important discoveries leading to radio and radar in the late 1800s and the early 1900s.
Heinrich Hertz, Guglielmo Marconi, Karl Braun and Lee DeForest are names to remember. Hertz discovered radio waves and showed that they could be focused into a beam and be reflected from objects. Marconi developed the first radio sending equipment. Braun invented a cathode ray oscilloscope and DeForest invented the radio amplifier tube.
Scientists at the Naval Research Laboratory did much of the early work in the United States on radar. In 1922, A.H. Taylor and L.C. Young detected reflections from a boat on the Potomac River while studying short wave radio.
In 1930, Young and L.A. Hyland observed similar reflections from aircraft. In 1934, Young proposed using pulses of radio waves as radar, the method most widely used today.
R.M. Page, another Navy scientist, developed a radar of this type and observed echoes from aircraft in December, 1934. By early 1936, pulse radar with a range of 25 miles had been developed. By 1938, a pulse radar had tracked an aircraft 100 miles. This is the kind of radar that was installed on 20 warships before the Japanese attacked Pearl Harbor in 1941.
The British became active in radar early in 1935 when the Air Ministry asked physicist Robert Watson Watt to work on antiaircraft weapons. By June of 1935 Watson Watt and a group of scientists developed a pulse radar capable of detecting aircraft at ranges up to 17 miles.
Before World War II started in September of 1939, the British had installed a chain of large radar warning stations on their shores. They also developed Ground Controlled Interception radar and Airborne Intercept radar for night fighter planes.
During the Battle of Britain, radar allowed artillery to fight off many air attacks.
During World War II, the Allied scientists scored big achievements by developing receivers, high powered transmitters and antennas to operate with microwaves. Microwaves made it possible to develop narrow beamed, highly accurate radars with small antennas for aircraft, ships and mobile ground stations.
American scientists did much of their radar work at the Radiation Laboratory, located at the Massachusetts Institute of Technology.
Radar became so effective in aiming aircraft guns that each side tried to jam the other's radar. Allied bombers carried radios to send signals that confused or blanked out enemy radar.
They also dropped tons of aluminum foil strips called window. These strips reflected false echoes on enemy radar indicators.
In the Pacific Ocean area radar gave the U.S. Navy superiority over Japanese forces in night naval battle.