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عبدالله المالكي الإثنين أبريل 06, 2009 10:53 pmAfter the discovery of infrared light by Herschel, a Danish physicist named Hans Christian Oersted found an electrical current that could change the direction of a compass' needle. André-Marie Ampère also found that different electrical currents could also attract or repel one another. It was in 1865 when James Clerk Maxwell proposed the idea of electromagnetism. He showed that electricity and magnetism were closely related and if made to surge back and forth, could produce alternating electromagnetic waves, which would move at the speed of light. Maxwell then concluded that light itself must be an electromagnetic wave.
Infrared, visible light, and ultraviolet are not the only types of waves. Further down past infrared lay microwaves, radar, television waves, and radio waves. Microwaves are thought to have been released during the Big Bang, which could have started the universe. These slow waves are used in microwave ovens to heat food by changing the alignment of water molecules. Even slower are radar waves. Radar is an acronym for "Radio Detection and Ranging." Radar scanners send out short radio waves and detect the echoes from objects in their path. Further down are television waves. These waves send out sound and pictures to our TV sets. The slowest known waves of all are radio waves. Not only produced by radio stations, radiowaves are sent out by stars and galaxies.
At the ultraviolet end of the spectrum are three other types of waves, all with higher frequencies than ultraviolet. Directly in front of ultraviolet is X-rays. While X-rays can pass through the soft parts of our bodies, they can not penetrate bone. This is why they are used today to take pictures of broken bones. Gamma rays are radioactive and are released by certain atomic nuclei. With their large amounts of energy they are able to penetrate metal and concrete and kill living cells. This type of wave is released by nuclear bombs, causing multitudes of destruction. The highest-energy and most frequent waves are cosmic rays. They are made up of particles of atomic nuclei, electrons, and gamma rays. The earth's atmosphere protects from these waves which come from outer space.
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Infrared, visible light, and ultraviolet are not the only types of waves. Further down past infrared lay microwaves, radar, television waves, and radio waves. Microwaves are thought to have been released during the Big Bang, which could have started the universe. These slow waves are used in microwave ovens to heat food by changing the alignment of water molecules. Even slower are radar waves. Radar is an acronym for "Radio Detection and Ranging." Radar scanners send out short radio waves and detect the echoes from objects in their path. Further down are television waves. These waves send out sound and pictures to our TV sets. The slowest known waves of all are radio waves. Not only produced by radio stations, radiowaves are sent out by stars and galaxies.
At the ultraviolet end of the spectrum are three other types of waves, all with higher frequencies than ultraviolet. Directly in front of ultraviolet is X-rays. While X-rays can pass through the soft parts of our bodies, they can not penetrate bone. This is why they are used today to take pictures of broken bones. Gamma rays are radioactive and are released by certain atomic nuclei. With their large amounts of energy they are able to penetrate metal and concrete and kill living cells. This type of wave is released by nuclear bombs, causing multitudes of destruction. The highest-energy and most frequent waves are cosmic rays. They are made up of particles of atomic nuclei, electrons, and gamma rays. The earth's atmosphere protects from these waves which come from outer space.
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