2013년 11월 4일 월요일

How Much Do You Know About Magnets

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The very first magnets were called magnetite or lodestone, and apparently the discovery was made by a Cretan shepherd called Magnes, who wondered why the iron tip of his crook was drawn towards a certain rock every time he passed it. Magnetism is one of the very first natural forces to have been discovered by humans. Legend has it that the ancient Greek scientist Archimedes used lodestone to remove nails from enemy ships, causing them to sink. Magnets are typically made of iron or steel, but can also be alloys of different elements such as copper and aluminum, such as rare earth magnets. There are two main types of magnets: permanent magnets and induced magnets. Permanent magnets create their own permanent magnetic field, while induced magnets are magnetized only temporarily, when they come into contact with a permanent magnet. For example, if you use a refrigerator magnet (a permanent magnet) to pick up a paper clip, the paper clip becomes temporarily magnetized and is an induced magnet for the time it is stuck to the refrigerator magnet. As soon as you remove it from the permanent magnet, however, it becomes de-magnetized and returns to its regular non-magnetic state. While there is actually nothing particularly "rare" or precious about rare earth magnets, they are the strongest kind of permanent magnets available and can lift up to four hundred times their own weight. This type of magnet was developed during the 1970s and 1980s and became serious competitors for other magnet types (such as ferrite magnets) in the 1990s,bell helmet, when prices became more competitive. Rare earth magnets are used in cell phones and computer hard drives and are treated with a special nickel coating to stop them from rusting, staining, chipping and breaking. Modern technology across all major industries requires the power of magnets; some of the common items in which magnets are used include televisions,dirt bike helmets, headphones, cordless power tools and bicycle parts. Magnets play an important part in the commercial world; conveyor magnets are used in manufacturing processes by getting rid of all metal waste on conveyor belt and leaving only those components, which are required for the next stage of manufacturing. Magnets are also used within the mechanics of large industrial machinery to make them quicker and more effective. There is ongoing research into the suitability and effectiveness of magnets in to address health complaints. It is believed that lodestones were used in acupuncture treatments way back in 2000 BC. Later the Greeks and Egyptians used magnets as cures for many conditions,bicycle helmets, including arthritis and baldness. While it is debatable whether magnets can make your hair grow back, they certainly still have a place within modern medicine. Many professional sportsmen use tectonic magnets for pain relief. There may be more to magnets than we realize, and further research is needed to establish their full potential.

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