Some version of the Hula-Hoop has been around for millennia, but the popular plastic version was introduced by Wham-O in the 1950s and quickly became a fad. Now, researchers have taken a closer look ...
To keep a Hula-Hoop aloft, it helps to be in shape — literally. Experiments with gyrating, hoop-slinging robots have revealed how these spinning rings stay up despite the pull of gravity. The shape of ...