What about magnetism? The nature of magnets is not understood even today, but its effects are known long ago. A magnet always has two poles, the north pole and the south pole, around which is a magnetic field. Rocky horror picture show don’t dream be it poster. This magnetic field is illustrated by iron scrap scattered around a magnet. Faraday saw that the magnetic field seemed to be a picture of a Chladni vibration, he saw that the place must be a magnetic wave.
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