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Spinning, rolling and hula hooping

By Carol Saab, 27 June 2013

What does hula hooping have to do with science? Quite a lot when we think about physics; namely energy, motion and torque. Check out the latest installment of our new video series to see some awesome hooping and how easy it is to mimic this movement with other objects.

Access the video transcript here.

Now you’ve heard about spolling – a combination of spinning and rolling. You could say this movement is how a hula hoop moves around a person, just as the washers move around the rod. If you’re still getting your head around spolling, take the two images below. You could say that Jasmine is rolling around the inside of the hoop like a wheel over the ground, while the hoop is spinning around Jasmine.

Jasmine, Double Helix editor, spolling with seven hoops.

Spolling can really be thought of as a combination of several physical laws. The spinning hoop has circular motion, while friction against the person causes the hoop to slow down. To keep the hoop moving, a torque force needs to be provided, like the hula hoop performer slinging the hoop around their body.

An aerial view of the path taken by a hula hoop (in purple). The red circle is the size of the hoop, the green circle is the person the hoop is ‘spolling’ around. The same applies to a washer moving around a rod. The path of the movement depends on the size of the washer (or hoop) relative to the rod (or person).

Want to use this video in the classroom? Download our teacher’s notes with curriculum links.