Bats and radar

THE WORD “RADAR,” as most engineering students already know, came into the language only a few years ago. During the early days of World War II, it was actually classified a military secret for the good reason that it explained in some detail the operation of this strategically important object-sensing device. The letters stand for “radio direction and ranging” which, of course, is the function of the instrument. In addition, the word is a palindrome which means it is spelled the same way forwards and backwards. In this way, it describes radar´s principle of operation: a high-frequency radio wave bounced directionally off a target yields the angle and distance information necessary to locate an object completely in space.