What is electromagnetism?

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What is electromagnetism? - PowerPoint PPT Presentation

What is electromagnetism?. Although electricity is all around us, in every object, it does not exist in large enough ______________ for us to use. There is nothing that gives us electricity directly. Electricity has to be made or _______________.

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What is electromagnetism?

Although electricity is all around us, in every object, it does not exist in large enough ______________ for us to use. There is nothing that gives us electricity directly. Electricity has to be made or _______________.

In 1820, a Danish scientist named Hans Oersted noticed that a wire with an electric _______________ running through it, acted like a magnet because it made a needle on a compass move. Oersted realized that the current flowing ___________ the wire was producing a magnetic effect. This was the discovery of ___________________.

If a coil of __________ is wrapped around a metal object and connected to an

energy source, the metal object will become ___________________, forming an electromagnet. The electromagnet will attract magnetic materials and can be made stronger by ________________ the number of coils of wire. When the flow of electricity is stopped, the electromagnet _________ its power. Electromagnets, therefore, are only _________________ magnets. They only work when electricity is _______________. Electromagnets are used in motors and many other useful devices such as doorbells, speakers, and one very important instrument, the telephone, invented by _____________________________________ in 1876. Today, enormous electromagnets are used in scrap yards. Can you think what they are used for?

English scientist named Michael Faraday. Although Oersted had earlier discovered the relationship between electricity and _______________, it was Faraday who was the first to discover that a magnet could cause an ______________ current to flow through a wire. While he was working with a current of electricity flowing through a wire, he noticed that nails were _______________ to the wires. Faraday thought that if electricity flowing through a wire could produce a _______________ effect, then perhaps the opposite was true. Perhaps a magnetic effect could _____________ an electric current.

By moving a magnet back and forth through a coil of ________, an electric

current flowed through the wire. When Faraday stopped moving the magnet, the electricity ______________ flowing. Faraday had invented the first generator. His generator produced a ________________ when a handle was turned. It consisted of a copper disc which was turned between the __________ of a magnet. Faraday’s work led to the invention of the electric motor and to the development of large power plants to generate _______________________.