Radar

        Today's society relies heavily on an invention taken for granted: radar. Just about everybody uses radar, whether they realize it or not. Tens of thousands of lives rely on the precision and speed of radar to guide their plane through the skies unscathed. Others just use it when they turn on the morning news to check the weather forecast.

        While radar seems to be an important part of our everyday lives, it has not been around for long. It was not put into effect until 1935, near World War II. The British and the Americans both worked on radar, but they did not work together to build a single system. They each developed their own systems at the same time. In 1935, the first radar systems are installed in Great Britain, called the Early Warning Detection system. In 1940, Great Britain and the United States install radar aboard fighter planes, giving them an advantage in plane-to-plane combat as well as air-to-ground attacks.

        Radar works on a relatively simple theory. It's one that everybody has experienced in their lifetime. Radar works much like an echo. In an echo, a sound is sent out in all directions. When the sound waves find an object, such as a cliff face, they will bounce back to the source of the echo. If you count the number of seconds from when the sound was made to when the sound was heard, you can figure out the distance the sound had to travel. The formula is:

                          (S/2) X 1100 = D

(Half of the total time times 1100 feet per second equals the distance from the origin to the reflection point)

        Of course, radar is a much more complicated system than just somebody shouting and listening for the echo. In fact, modern radar listens...