Magnets play a very important role in the electricity that we use daily. Most magnets are made from iron or steel, a metal made by adding carbon and other substances to iron. Magnets can also be made from more expensive metals such as nickel and cobalt. Strong magnets are made by mixing aluminum, nickel, cobalt, iron and samarium. Magnets need to be treated carefully or they will lose their magnetic power. A magnet's attraction is strongest at two points called poles, a north pole and south pole. Magnets will attract each other if opposite poles are near each other. Unlike poles attract, like poles repel.
The point where you can feel the magnet's attraction on an object is called a magnetic field. The field is stronger the closer you get to the magnet. Magnets are used in many items you use daily. Electric motors use magnets and many household appliances use motors. They are also used in cassette records, television, speedometer and burglar alarms.(Ardley,138)
Electro Magnets
We have noted that magnets have two poles, north and south while electricity has two charges positive and negative. In both cases opposites attract and similar repels. Poles and charges follow the same rules. What are some other connections?
A Danish physics name Osterd discovered the connection between electricity and magnets, magnetic field around a current. His discovery led people to believe that it was possible to make magnets with an electric current.(Gardner,71)
Most of the electricity we use is supplied by generators, which contain magnets. An English scientist called Michael Faraday discovered how to use magnets produce electric current. This discovery was used to invent the generator. He connected a coil of wire to the galvanometer, an instrument used to detect electric currents. When a bar magnet was pushed through coils, the needle on the galvanometer moved, proving an electric current flowed through the wire.(Gardner,97)
About 40 years after Faraday discovery, Thomas Edison and Joseph Swan built a DC generator. Edison used the generator to light his laboratory than later the streets of New York. Edison loved his DC generator while other scientist found fault with it.(Rawsthorne,2)
George Westinghouse bought Nikola Tesla's patented motor for generator alternating current. The AC generator allowed the transmission of larger blocks of electricity and more power from higher voltage through transformers. This would have been impossible with DC generators. Tesla's name was give to the unit of measurement of magnetic fields.(Rawsthorne,3)
In electric power stations huge generators are used to make electricity. These generators are turned using steam produced by boiling water. Large - scale electricity from a generator became practical with James Watt's steam engine. His name was given to the electric unit of power, the Watt. (Rawsthorne,3)