Electricity and Magnetism
DEM24.1 - 3D Magnetic Field
Objective:
- To show the shape of the magnetic field about a cylindrical magnet, in three dimensions.
Apparatus:
- 3-D Magnetic Field demo block (Pasco SE-8603)
- Bar magnet set (Pasco SE-8604)
Method:
The clear block is rotated slowly in all directions to disperse
the iron filings in the mineral oil. DO NOT SHAKE THE BLOCK. One cylindrical
magnet is centred in the hollow core. The iron filings take the 3-dimensional
form of the magnetic field in a short time.
Variation:
Insert two magnets, with like poles facing. The iron filings show the
two like fields repelling the filings (i.e. the two magnetic forces opposing
each other).
Notes:
- By viewing the block from one end, one observes the rarely seen 3-dimensional field distribution.
- Do not shake the block. It takes a long time for bubbles to be released from the mineral oil.
- Do not slide the block on any surface. Scratches prevent the clear viewing of field patterns.
- Return the magnets to their holding slots with keepers in place, and the magnets in series loop.
- Do not drop or overheat the clear block.
- The plastic block is not suited for overhead projection, as depth of field is inadequate and heating may occur
Watch a 3D Magnetic Field Demonstration
on Youtube video (not produced by BCIT)
