magnetisation

Everyday

1. (science) The process of making something into a magnet. tree →
2. (science) How strongly something is magnetised, or the state of being magnetic. tree →

In the lessons

In science lessons on magnets you can magnetise an iron nail or a needle by stroking it with a magnet in one direction; this is magnetisation. Heating or hitting a magnet can destroy its magnetisation. It explains how compasses are made and how old computer disks stored data. Phrases: «the magnetisation of iron», «lose magnetisation».

Examples

• Stroking a needle with a magnet causes magnetisation. tree →
• After magnetisation, the needle could pick up paper clips. tree →
• Dropping a magnet can weaken its magnetisation. tree →
• We tested the magnetisation by seeing how many pins the nail could hold. tree →
• The magnetisation of the steel lasted for weeks. tree →
• Heating a magnet strongly can destroy its magnetisation. tree →
• Electric currents can also cause magnetisation, like in an electromagnet. tree →
• Rocks keep a record of the Earth's magnetisation from long ago. tree →

Note

Uncountable in normal use. UK/Australia/NZ spelling «magnetisation», US/Canada spelling «magnetization» – both correct. Verb: magnetise (magnetize). Only some metals (iron, nickel, cobalt, steel) can be magnetised; aluminium, copper and gold cannot. Not a maths word, but magnetisation can be measured and compared in a fair test.