ELECTRICITY MEETS MAGNETISM

 There are two ways to produce a magnetic field - using a permanent magnet or an electromagnet ( a coil of wire through which a current flows). The second of these shows there is a close connection between electricity and magnetism. This was discovered by Hans Christian Oersted, a Danish scientist, early in the 19th century. He noticed that both static electricity and magnetism showed similar patterns - attractive and repulsive forces, two types of charge or pole, a force that gets weaker at a distance, and so on. Most other scientists thought this was just an interesting coincidence, but Oersted thought there was more to it. He was sure he could find a link between electricity and magnetism - and he did!


   In 1820, Oersted gave a lecture on electricity. He described a ship that has been struck by lightning. Its compass was affected so that its north and south poles were reversed. Oersted was certain this proved the link between electricity and magnetism. Then a thought struck him - he could try an experiment there and then test his idea. On his bench, he had a wire and a compass. He placed the compass under the wire. When his assistant connected to a battery so that current flowed through a wire, the compass needle moved. At the time, no one was very impressed - not even Oersted. But the more he thought about it, the more he realised that he had observed something significant. The current in the wire was producing a magnetic effect, which was acting on the wire, he discovered that the magnetic effect showed a circular pattern around the current. The study of electromagnetism had begun.

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