INTRODUCTION TO THE ELECTROMAGNETIC SPECTRUM
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| electromagnetic spectrum_chem.eng.21 |
When you tune your radio, watch TV, send a text message, or pop popcorn in a microwave oven, you are using electromagnetic energy. You depend on this energy every hour of every day. Without it, the world you know could not exist. Electromagnetic energy travels in waves and spans a broad spectrum from very long radio waves to very short gamma rays.
The human eye can only detect only a small portion of this spectrum called visible light. A radio detects a different portion of the spectrum, and an x ray machine uses yet another portion. NASA’s scientific instruments use the full range of the electromagnetic spectrum to study the Earth, the solar system, and the universe beyond. OUR PROTECTIVE ATMOSPHERE Our Sun is a source of energy across the full spectrum, and its elec tromagnetic radiation bombards our atmosphere constantly. However, the Earth’s atmosphere protects us from exposure to a range of higher energy waves that can be harmful to life. Gamma rays, x rays, and some ultraviolet waves are “ionizing,” meaning these waves have such a high energy that they can knock electrons out of atoms. Exposure to these high energy waves can alter atoms and molecules and cause damage to cells in organic matter. These changes to cells can sometimes be help ful, as when radiation is used to kill cancer cells, and other times not, as when we get sunburned.
Below is the slide introduction about Electromagnetic specturm
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