Hula Hoop Demo
Hula Hoop Demo

 

Code Number: 3A95.63

Demo Title: Hula Hoop

Condition: Excellent

Area of Study: Oscillations & Acoustics, Resonance

Procedure:

The Hula Hoop can be used for a variety of demonstrations.  

Friction:  It is the friction between your clothes and the hoop that keep it spinning.

Resonance:  Your hips need so swing at the right frequency to keep the hoop spinning.  

Moment of Inertia:  Add identical masses to two opposite places inside the hoop.  You will find it much easier to swing with your hips.  Also, hold the hoop vertically with the weights at the top and bottom ( one weight under your hand and the other at the bottom of the hoop near the floor).  You will find that in this configuration the hoop is easy to twist about a vertical axis.  Now change the orientation so that the weights are at the 3 and 9 o'clock positions.  Twisting the hoop about a vertical axis again should reveal that the hoop twists much more slowly.  

References:

  • Alexander P. Seyranian, Anton O. Belyakov, "How to Twirl a Hula Hoop", AJP, Vol. 79, # 7, July 2011, p. 712.
  • T. K. Caughey, "Hula-Hoop: An Example of Heteroparametric Excitation", AJP, Vol. 28, #2, Feb. 1960, p. 104.
  • 50 Fun Experiments for the Mad Scientist in You, "Hula-Hoop Observation",  National Geographic Kids, p.  42.
  • H. Richard Crane, "Chattering, The Chatterring, and the Hula Hoop", How Thing Work ( 1983 - 1995 ), p. 117.
  • Jearl Walker, "1.84, Spinning Hula Hoops and Lassos", The Flying Circus of Physics Ed. 2, p. 43.
  • Ed Sobey, Woody Sobey, "Hula Hoop", The Way Toys Work, p. 68.