the.com/iron filing
Metal dust that turns invisible magnetic fields into something you can actually see.
means A tiny shaving of iron, shaved or ground off a larger piece, so fine it behaves almost like dust.
from Straightforward compound: 'iron' (the metal, from Old English 'īsern', itself borrowed far back from a Celtic word for the metal that gave Europe its name for the Iron Age) plus 'filing', the noun use of 'file' — a tool name going back to Old English 'fēol', used for scraping metal into shape since long before anyone thought to sprinkle the scrapings over a magnet to watch field lines bloom.
- classroom trick
- reveals field lines around a magnet instantly
- made by
- filing or grinding iron down to shavings
- fun hazard
- clumps violently if you bring magnets too close
- not just iron
- often alloyed, so technically slightly impure