Modern Hula-Hoops are plastic rings you twirl around your body by moving your hips. This swiveling motion is similar to that ...

The gyrations of hoop-slinging robots reveal that hourglass-shaped objects are best at keeping a hoop in the air.

The Hula-Hoop is one of the most famous toys in history, but the science behind it has gotten little attention. Some of us are master twirlers, while others can't manage more than one spin.