Variable Gap Magnet for Physics Demonstrations Base Size_8 x 5" and the triboelectric series

and the triboelectric series

paired with 4mm sockets so iron-filing patterns can be mapped around a current-carrying conductor for Oersted's experiment

this resistance box at plus-or-minus 1% on each step replaces dozens of fixed resistors at the bench

exposing chamber interior and septal structure for entry-level cardiac teaching

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

Variable Gap Magnet for Physics Demonstrations Base Size_8 x 5" and the triboelectric seriesAdjustment 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.