Aluminum Flip Top and Magnetic Stirrer http://physicstoys.blogspot.com/p/physics-toy-store.html Dynamic magnetic fields from rotating neodymium magnets in the base induce electric currents to flow in the conducting aluminum of the top. These electric currents then produce an opposite magnetic field of their own via Lenz’s Law. With the top now having a temporary magnetic field the magnets in the stirrer can spin it up. Tippie-tops are a famous physics toy that flip over when spun at sufficient r