Year of Invention: 1935
What Is It? A device that uses the reflections of pulses of high-energy radio
waves to detect and locate moving metal objects.
Who Invented It? Robert Watson-Watt (in England)
Radar is a lifesaver. During World War II, radar stations warned England of approaching German air raids. Airborne radar detected German submarines and made Atlantic and Mediterranean shipping safer for thousands of sailors.
Radar is the essential heart of all air traffic control and has made commercial air travel safe. Marine radar systems have reduced ship collisions and deaths by over 90 percent. Since the early 1950s, improved weather prediction has been based on radar systems.
What Did People Do Before?
Bats have used radar to locate both food and obstacles for millions of years. There are even moths that have developed “stealth” technology using thick, powdery coatings to absorb a bat’s radar beams and avoid creating the reflective echoes that guide a hungry bat to dinner.
In 1888, Heinrich Hertz discovered radio waves. In 1900, Nikola Tesla described a system for using Hertz’s radio waves to identify and locate moving objects. However, few paid any attention to this seemingly wild idea.
In 1918 a detection system similar to radar (active sonar) was invented and tested. Sonar uses sound waves and is used underwater where low-frequency sound waves can travel for thousands of miles.
The equipment needed to build a successful radar unit existed in 1915. However, no one thought of building one for another 20 years.
In 1924, Sir Edward Appleton bounced radio waves off the upper atmospheric ionosphere (part of his experiments to prove that the ionosphere actually existed). These experiments reminded researchers in the United States, France, Germany, the United Kingdom,