Variable Gap Magnet for Physics Demonstrations Base Size_8 x 5" 8mm rod attachment and a

8mm rod attachment and a centered 50mm aperture together hold a lens square against an optical-bench rail for repeatable refraction

U-magnet and brass-rail apparatus that demonstrates the motor effect

Sized for compact classroom display

producing distinct audible pitches at varying spin speeds to relate rotational frequency to perceived sound frequency

Variable Gap Magnet for Physics Demonstrations Base Size_8 x 5" 8mm rod attachment and aAdjustment screws (3 x 1 inch) on a metal base position two neodymium magnets, varying the pole gap from 0. 4 to 8. 5cm and field strength from 100 to 7500 Gauss across the working volume.