Variable Gap Magnet - EM-8618



The redesigned Variable Gap Magnet is rugged and durable while providing excellent results as a demonstration tool.  The two one inch (2.54 cm) diameter neodymium magnets are mounted on a heavy-duty cast iron base which has a threaded hole for mounting on a support rod to provide even more versatility.

The gap may be varied from 0.5 cm to 8.9 cm using the adjustment screws.  Two flat pole pieces are also included to provide a uniform magnetic field when needed.

Combine the Variable Gap Magnet with the Magnetic Force Accessory or purchase both as the Magnetic Demonstration System.

Together they may be used to demonstrate magnetic induction, the magnetic force on a current carrying wire (shown to the right), magnetic damping or diamagnetism and paramagnetism.

Note:  the example on the right uses the Variable Gap Magnet and Magnetic Force accessory as well as banana plug patch cords, a ringstand and base and power supply which are all sold separately. 

Demonstrate Diamagnetism and Paramagnetism

  • The diamagnetic glass rod (shown on the left side of the image) aligns transverse to the field while the paramagnetic aluminum rod (shown on the right side of the image) aligns with the field.
  • The glass and aluminum rods are available as part of the PASCO Magnetic Force Accessory which includes additional equipment for use with the Variable Gap Magnet. The Variable Gap Magnet and Magnetic Force Accessory may be purchased together as the Magnetic Demonstration System.


Approximate magnetic field strength without pole pieces (in tesla/gauss)

0.5 cm Gap
  • 1.02 T / 10200 G at poles
  • 1.00 T / 10000 G between poles
0.6 cm Gap
  • 1.00 T / 10000 G at poles
  • 0.95 T / 9500 G between poles
1.0 cm Gap
  • 0.85 T / 8500 G at poles
  • 0.75 T / 7500 G between poles
8.9 cm Gap
  • 0.55 T / 5500 G at poles
  • 0.35 T / 3500 G between poles

Buying Guide