5H10.30 Magnetic Field of a Bar Magnet


Magnetic field lines


The magnetic field lines of a bar magnet can be viewed by using compasses or by shaking iron filings onto a platform above the magnet.



  • [1] Bar magnet
  • [1] Shaker of iron filings
  • [3] Compass
  • [1] Plexiglas platform
  • [1] Blank white sheet of paper
  • [1] Document camera or overhead projector

Classroom Assembly

  1. Place the magnet on top of the paper in view of the document camera or overhead projector.
  2. Place the Plexiglas platform on top.
  3. If using the iron filings, remove paper underneath the shaker cap.

Important Notes

  • Iron filings can be messy.


  1. Place compasses in position around the magnet or carefully shake iron filings onto the platform.
  2. Remove compasses or put the iron filings back in the shaker using the paper.
  3. If in a great hurry, use the magnet to pick up the remaining iron filings.


Additional Resources


  • PIRA 5H10.30


  • Don't attempt this at home!

Last revised

  • 2017


  • To remove iron filings from the magnet, use a rare earth magnet inside a plastic bag.

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If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.