Data Bases • Custom Term Papers • Free Term Papers • Free Research Papers • Free Essays • Free Book Reports • Plagiarism? Links • Top 100 Term Paper Sites • Top 25 Essay Sites • Top 50 Essay Sites • Search 97,000 Papers @ DirectEssays.com • Search 101,000 Papers @ ExampleEssays.com • Search 90,000 Papers @ MegaEssays.com Free Essays • Term Paper Sites • Chuck III's Free Essays • Free College Essays • TermPaperSites.com • My Term Papers • Get Free Essays • Essay World • Planet Papers	Search Lots of Essays Back to Subjects - Physics lasers and stuff lasers and stuff Laser, pronounced LAY zuhr, is a device that produces a very narrow, powerful beam of light. Some beams are thin enough to drill 200 holes on a spot as tiny as the head of a pin. The ability to focus laser light so precisely makes it extremely powerful. For example, some beams can pierce a diamond, the hardest natural substance. Others can trigger a small nuclear reaction. A laser beam also can be transmitted over long distances with no loss of power. Some beams have reached the moon. The special qualities of laser light make it ideal for a variety of applications. Some types of lasers, for example, are used to play music, read price codes, cut and weld metal, and transmit information. Lasers can also guide a missile to a target, repair damaged eyes, and produce spectacular displays of light. Still other lasers are used to align walls and ceilings in a building or to print documents. Some lasers even can detect the slightest movement of a continent. Lasers vary greatly in size. One is almost as long as a football field. Another type is as small as a grain of salt. A typical laser has three main parts. These parts are (1) an energy source, (2) a substance called an active medium, and (3) a structure enclosing the active medium known as an optical cavity. The energy source supplies an electric current, light, or other form of energy. The atoms of the active medium can absorb the energy, store it for a while, and release the energy as light. Some of this light triggers other atoms to release their energy. More light is added to the triggering light. Mirrors at the ends of the optical cavity reflect the light back into the active medium. The reflected light causes more atoms to give off light. The light grows stronger, and part of it emerges from the laser as a narrow beam. Some beams are visible. Others consist of invisible forms of radiation. There are four main kinds of lasers. They are solidstate lasers, semiconductor lasers, gas lasers, and dye lasers. In 1960, the American physicist Theodore H. Maiman built the first laser. At first, lasers had few uses, and scientists often thought of them as "a solution looking for a problem." Today, however, lasers rank among the most versatile and important tools in modern life. How lasers are used Lasers can do a number of incredible things. Their special qualities make them particularly useful in recording, storing, and transmitting many kinds of information. Lasers also are valuable in such activities as scanning, heating, measuring, and guiding. As a result of their wide use, lasers can be found in equipment used in homes, factories, offices, hospitals, and libraries. Recording, storing, and transmitting information. The most common uses of lasers include the recording of music, motion pictures, computer data, and other material on special discs. Bursts of laser light record such material on the discs in patterns of tiny pits. The discs with recorded music and computer data are called compact discs (CD's). A laser beam's tight focus allows much more information to be stored on a CD than on a phonograph record, making CD's good for holding data as well as music. Some CD's even can hold an entire encyclopedia. A disc used for storing data is usually called a CD-ROM (Compact Disc Read-Only Memory). Such discs store databases (large files of information held in computers) and are used widely by businesses, libraries, and government agencies. Lasers can also read and play back the information recorded on discs. In a CD player, a laser beam reflects off the pattern of pits as the compact disc spins. Other devices in the player change the reflections into electrical signals and decode them as music. More lasers are used in CD players than in any other product. Bibliography: aafdafdaf Word Count: 644
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