Variable Gap Magnet for Physics Demonstrations Base Size_8 x 5" paired with 4mm sockets so

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

Used to read spectral lines against a 400-700nm graduated scale

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

Economy 25 by 5mm ceramic disc magnet

Variable Gap Magnet for Physics Demonstrations Base Size_8 x 5" paired with 4mm sockets soAdjustment 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.