Radio waves are the lowest frequency waves on the
electromagnetic spectrum. They are made of electromagnetic energy, moving in a wave
pattern, that can pass through both a medium (like air) and also through a vacuum. The
frequency and the wavelength determine what "kind" of wave you get - radio, light,
x-ray, etc. They all travel at light speed, and all can be reflected or refracted the
way light can.
There are many examples of why radio waves
are significant. Because they can cross space, they are used extensively by astronomers.
Most stars emit radio waves, and by studying these we can learn about the structure and
history of the universe; some of the largest telescopes in the world don't use light at
all, they are so-called radio telescopes.
Radio waves are
also used for communications. In addition to commercial radio broadcasts, radio waves
operate short-wave and citizen's band radios, walkie-talkies, and cell phones. Microwave
ovens use specific wavelengths of radio waves to heat
food.
The other significance is that large doses of radio
waves are known to be harmful to the human body, essentially the equivalent of sticking
your head in the micorwave. This is why so many studies are being done to determine
whether cell phones cause cancer or not. The jury is still out on that at the moment,
but scientists are urging people to be careful, just as a
precaution.
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