Tan – it is protective reaction of skin to ultraviolet light. For blacks, this protection genetically innate. Following are the wave ultraviolet visible spectrum. And the main feature of this type of radiation is its visibility to the human eyes. And, in my opinion, this is the most interesting case of electromagnetic radiation.
Why? Let me explain. It so happened that this kind of waves the earth misses the best. And again, "so happened" that this kind of waves radiated from the sun. And from the sun are different types of radiation, but the most active sun emits visible light. Already these two facts might be interested in any. But the fact that this type of radiation perceived by our eyes, we can not be viewed as a coincidence, but as human evolution, and many living organisms. This is truly exciting.
There is a wave with even higher wavelengths: infrared radiation. Their also referred to as "heat." These rays are emitted by all heated bodies, even if the body is not lit. This type of radiation is absorbed by air molecules, particularly carbon dioxide. In space, carbon dioxide is not so much therefore, heat rays, without loss of income to our planet. But because of the air earth misses a very small part of the radiation, to prevent from too much heat. The earth is heated by the light radiation. And now imagine: light radiation warmed the earth, and now the land itself can radiate heat, ie infrared radiation. But all the same air makes this radiation out into space. I wonder, is it? Carbonic Gas does not land too hot, but cool and he does it as well. The latter, which will be discussed are the radio waves with the greatest of these long wave Radio waves can easily pass through earth's atmosphere. But there is this kind of radio waves, which is called "short", the radio waves reflected from one of Earth's atmosphere (called ionized). Because of this phenomenon and made possible link between radio stations. Now let's sum up what has been said: The distance between two neighboring crests is called wavelength; properties of electromagnetic radiation depends on its wavelength, X-rays: open Wilhelm Conrad Roentgen rays have a good permeable ability, magnetosphere retains this radiation from outer space, ultraviolet radiation: does not pass through the ozone layer may be adjacent to the light rays, a tan – protective reaction of skin to ultraviolet light, Light radiation: the land passes without interference, mostly emitted by the sun, perceived by our eye, infrared radiation: absorbed by the molecules of carbon dioxide, due to which the land does not pass infrared radiation in large quantities; Radio waves: no problems going through the atmosphere, "short" radio waves reflected from the ionized layer;