Making a magnet, and destroying one · Simulation

Material

How magnetised is the bar?

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The tiny magnets inside point every way in an unmagnetised bar. Line them up and the ends become poles.

Make a magnet

Switch on the coil and its field lines the tiny magnets up. When the current stops, soft iron lets go and steel holds on: that is the syllabus idea of temporary and permanent magnets.

Beyond the syllabus Hammering in the Earth's field, and stroking with the magnet (drag it along the bar, one direction, lift it clear to go back), also work.

Destroy a magnet Beyond the syllabus

Heat it: 20 °C

Above about 770 °C (the Curie temperature of iron) the tiny magnets are shaken out of line. These methods are not examined in 0625, but they show what magnetism inside a bar really is.