a wooden tippe top — a small spinning top that flips itself upside down mid-spin and keeps going on its stem. painted wood, about 1.3–1.4 in / 3.3–3.6 cm tall, with a little wooden stand. two patterns, or both.
spin it ball-side down. a few turns later it starts to wobble, tips over, and comes up standing on its own stem — still spinning, now upside down. nobody touched it.
there's a photo from 1954 of wolfgang pauli and niels bohr, two nobel prize physicists, watching one of these spin. it's a toy that has been making very smart people stare at the floor since a german nurse named helene sperl patented it in 1891.
what's going on: friction where the ball rubs the table pushes it over. the spin doesn't stop, the top just turns itself around to keep it. the full explanation is hard enough that it showed up as a problem at the 2019 asian physics olympiad.
heads up: the flip needs a fast twist and a smooth, hard surface — a bare table, not a tablecloth or a rug. the first few tries usually just spin like a normal top. it's also small, about walnut-sized, so it's a desk thing, not a dog thing and not for little kids.
material — painted wood top with a natural wood stem; darker wood stand
size — top alone: harlequin 1.4 in / 3.6 cm tall, rainbow 1.3 in / 3.3 cm tall · 1.7 in / 4.3 cm tall on its stand · stand 1.1 in / 2.8 cm across
colors — harlequin (red, yellow and blue petals) · rainbow (stripes, purple inside) · or both
for — desks, physics people, anyone who likes being outsmarted by a very small object
heads up — needs a quick twist on a smooth hard surface; small parts, keep away from dogs and little kids
no instructions included. it already knows which way is up. it just disagrees.
go play.
