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Magnets and Materials
磁铁与材料
Types of magnets, magnetic vs non-magnetic materials, the two poles. Key: not all metals are magnetic — aluminium and copper are non-magnetic.
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Attract, Repel and Direction
吸引、排斥与方向
Unlike poles attract, like poles repel. How to confirm an object is a magnet (must repel). Freely suspended magnet points North-South. Earth as a giant magnet.