Radio Detection And Ranging systems, known as radar, were developed in Britain in the 1930s as a defense against German bombing raids. While their military use flourished during World War II, radar was not used commercially until the 1950s. Today, radar has become commonplace. Flight crews routinely use radar tracking features to navigate aircraft to their destinations safely. Radar is also commonly used by meteorologists to track weather patterns. For most television viewers of the weather forecast, the image of a green, circular radar screen--complete with a sweeping arm of light--is a familiar one. Using a high-intensity microwave transmission, meteorologists can detect and follow large masses of precipitation, whether they be rain, snow, or cloud. A beam of pulsed microwaves travels until it hits an obstacle (for meteorological purposes, a cloud or band of precipitation). It is then reflected back to the source, where it is...