5H10.30 - Projection of the Fields of Permanent Magnets
Show the shape of the magnetic field around bar magnets.
InstructionsA set of bar magnets is mounted on glass plates in different configurations so that they may be set on the overhead for projection. If they are now sprinkled with iron filings, the filings will orient themselves with the field lines and the pattern of the lines is projected on the screen. Fairly course filings are superior to fine ones since they do not cluster as badly. It helps to tap the plate gently to get the filings to align with the field.
An alternate set-up is available upon request.
A hexagonal array of permanent magnets between glass plates is used instead of bar magnets. A projectual (iron filings and oil encased in acrylic) or a transparency sheet with iron filings can be used to highlight the magnetic field lines.