[Physics] Does hitting metals magnetize them

electromagnetism

I was on my workshop lab today and had to file (rub on metal surface with rough surface to smooth-en it) an iron bar. It made iron dust fall of the surface. To mark some points on the bar I then had to hammer a pointed another Iron bar over the former. What I noticed is that the iron dust that had previously fallen off were clinging on the top circumference of the pointed bar.

I have two probable explanations for this

  1. The iron dust being small acted as magnets as there are fewer magnetic domains and they essentially align on single direction so that the dust were attracted.
  2. Hitting the top of bar somehow could have magnetized the bar so that the dust were attracted

Am I correct with one or both of these explanations?

Best Answer

The impact of the hammer with the iron nail causes the magnetic domains within the nail to break loose from their current orientation. The Earth's magnetic field will then reposition the domains into a new orientation parallel with the Earth's magnetic field.

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