Conservation of Angular Momentum Fidget Spinner

myminifactory

June 2017 Update: I uploaded an all-new version that works beautifully without a ceramic bearing. This spinner picks up speed as it slows down, with magnets moving to the outer position initially and then shifting to the inside position as it starts to slow, causing it to spin even faster. Inspired by the amazing example prints in whosawhatsis's book, 3D Printed Science Projects*, I recommend using: 1. A non-magnetic ceramic 608 bearing: The bearing needs to be specifically chosen for its non-magnetic properties, otherwise the magnets will stick to it and add excessive drag. 2. Four ten millimeter cylinder magnets*: Be careful with these magnets - they're extremely strong and somewhat brittle. They should be set to attract each other, inserted from the bearing cavity, and held captive by a small ledge near the bearing so they don't hit the bearing when they move in. This ledge makes it slightly harder to insert the magnets, but once they're past it, they'll move freely. I used Atomic Filament Amethyst Violet Gemstone Translucent PLA for this project.