1M40.94 - Fiddlesticks or Gyro Ring, and Hula Hoop

See first paragraph of procedure.
See second paragraph of procedure.
Code Number:
Demo Title:
Fiddlesticks or Gyro Ring, and Hula Hoop
Energy Conservation
Area of Study:
Fiddlesticks (spinning rings) - straight and circular version.

Fiddlesticks is a demonstration that shows the transfer of potential energy into rotational kinetic energy. Slide the rubber grommets to the top of the rod and give them a slight spin. You will see that as the grommets spin increases their rate of fall will decrease and vice versa. Another way to use this to show energy transfer is to only let the bottom grommet start spinning down the rod. Then let the top grommet which has no spin fall onto the bottom grommet which has spin. The bottom grommet will transfer some energy to the top grommet and start it spinning. When this happens the top grommet will appear to jump upward away from the bottom grommet.  

The circular version allows you to do this experiment in a continuous fashion.

  • H. Richard Crane, "Chattering, the Chatterring, and the Hula Hoop", TPT, Vol. 30, # 5, May 1992, p. 306.
  • Martin Gardner, "The Waltzing Egg Shell", TPT, Vol. 29, # 5, May 1991, p. 315.
  • Tik Liem, "The Spinning Rings", Investigation to Science Inquiry, p. 193.
  • George M. Hopkins', "Rod and Ring Experiment", Experimental Science, Volume Two, p. 200.
  • Martin Gardner, "The Waltzing Eggshell", Science Tricks, p. 37.
  • Jearl Walker, "1.160, Fiddlesticks", The Flying Circus of Physics Ed. 2, p. 74.
  • 2.34:  Jearl Walker, "Fiddlesticks", The Flying Circus of Physics with Answers.
  • Neil Downie, "1: Hovering Rings", Vacuum Bazookas, Electric Rainbow Jelly, p. 3.

Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.