Tautochrone Track

This desktop experiment tests the principle of a cycloid track, where no matter where you place a ball on the track, it should reach the bottom in the same amount of time. Impossible? Apparently not!

Requires 12 6mm x 3mm disc magnets, and 2 springs out of a pilot G2 pen (buy a 12 pack and you can swap the cartridges to not waste pens). Of course you also need steel balls. The exact size can vary, but these 5mm steel bearing balls are affordable and should work well.

See the process video for assembly and demo