Rattleback- A rebel top

A phenomenal physical curiosity! A semi-ellipsoidal top that spins in only one direction. This toy seems to violate the angular-momentum conservation law of physics. It's a mind-bending physics experiment right in your own hands! With its unexpected behavior and fascinating motion, experimenting with the Rattleback will leave you feeling like a genius physicist... Behold the mysterious RattleBack, with a property that amuses.One way, it will spin; the other way, it refuses. Exciting and mysterious. Part of Copernicus Toys Compact Curiosities line.