magnets
For levitation in ancient times men knew of a special kind of rock that could pull other rocks of the same kind and pieces of iron toward themselves. They were called lodestones. Today man uses the same force exerted by electromagnets and permanent magnets to provide magnetic aide to trains and more efficient power generators. Magnetism is defined as the force exerted by a magnetic field. A magnetic field is defined as the energy exerted by the magnet. It is caused by the alignment of the domains (sub-atomic particles) of an object. When the domains are lined up they produce magnetism. When the domains are not lined up then they cause the object to be demagnetized (having no magnetic power). Materials such as air, wood, copper, and water do not respond to the power of magnets. Electromagnets, like permanent magnets, have poles and magnetic fields. Actually, whenever an electrical current passes through a wire, it produces a magnetic field. Every electrical appliance or cord has a weak magnetic field around it. The difference between an electromagnet and a permanent magnet is that you can reverse direction of the current in an electromagnet. The greatest electromagnet that is known today is the Earth. The planet's magnetism come
s from electronic currents deep within the Earth. Scientists believe that there is a region of molten iron surrounding the Earth's core. Scientists can determine changes in the Earth's magnetic field by studying old maps. The Earth's poles have drifted, ad continue to drift, westward. Small electronic needles have been found in the Earth that are frozen pointing at an old north pole, close to what is now the south pole. It is believed that the Earth's poles have actually reversed. The Germans also have their own magsusp (magnetic suspension) system called Transrapid. The bottoms of the cars are wrapped around a T-shaped track, and attracted up to a 3/8 inch servo-controlled gap. Propulsion is caused by the magnets similar to Japan's ML magnets. The program began in 1969, and the latest prototype is the Transrapid 07, which reached a top speed of 310mph. This was only 11mph under the Japanese MLU002N. Transrapid expects to build a rail line linking Hamburg and Berlin. The cost for the project is estimated at $6 billion, two thirds of which will be provided by the government. On a 180-mile track the trains are supposed reach speeds of over 250mph, and cover the distance in less than an hour. The United States also proposed a maglev system in the 1970s called Magnaplane. It was designed by Henry Kolm and Richard Thornton at MIT. A 1/25 model was made but funding was cut by congress. This new form of transportation may arrive late due to "perpetual congressional gridlock". Magnets have also, and probably still wil
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Approximate Word count = 1029
Approximate Pages = 4 (250 words per page double spaced)
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