Lisa Kay Wiker, age 11, of Lancaster, Pa., for her question:
HOW DO RADIO WAVES TRAVEL?
Since radio waves carry our radio and TV programs, we tend to think they belong to the planet earth. But this is only a tiny portion of the total picture. For radio is a stupendous cosmic source that spans the entire universe. It travels in its own way at its own speed and we merely tack on signals to be carried from here to there.
Radio is a form of electromagnetic energy, related in some mysterious way to both electricity and magnetism. Other forms of electromagnetic energy include infrared, ultraviolet, X rays and ordinary light. All of them travel in pulsing waves of assorted lengths. Ordinary light waves are longer than X rays. Radio waves are still longer.
All these wavelengths of energy fan out from a source, which may be a starry sun or a man made generator.
The beams fan out in straight lines, all traveling at the speed of light. This is about 186,282 miles per second fast enough to whip around the earth's equator more than seven times in a single second.
The radio beams that carry our programs are generated at a broadcasting station. They fan out in straight lines, traveling silently and invisibly at the speed of light. Elaborate electronic tampering is needed to make them carry our messages.
At the radio studio, sights and sounds are translated into electrical impulses. These are hitched into the carrier beams and travel with them as they go. The carrier beams cannot bend around the curved surface of the earth. But they can be angled.
High up in the atmosphere is a layer with lots of ions, or charged particles. Some of the carrier beams zoom up to this ionosphere and get bounced back to angle down again, miles from the broadcasting station. There they are picked up by clever devices, magnified and relayed forth on another giant stride around the curved globe.
These carrier beams, with their silent invisible coded signals, are picked up by your receiving set. There the coded signals are separated from the carrier beams. They are translated back to the original sounds and sights added at the studio, magnified and displayed as a program.