1D52.30 - Water Centrifuge with Cork and Balls

Code Number:
Demo Title:
Water Centrifuge with Cork and Balls
Central Forces
Area of Study:
Fluid Dynamics
2-Liter pop bottle, steel balls, marbles, cork.

Place the steel balls or marbles and a cork  in a 2-Liter pop bottle and fill with water.  Place the bottle on its side in the middle of the rotating air table and give it a spin.  The cork should move to the center of the bottle while the marbles or steel balls should move to the ends of the bottle.

  • Keith Bellof, "Student-Discovered Gem", TPT, Vol. 45, # 8, Nov. 2007, p. 524.
  • Martin Gardner, "The Marble and the Cork", TPT, Vol. 34, # 3, p. 146, March 1996. 
  • Thomas J. Pickett, "The Marble, Cork, and Centrifuge", TPT, Vol. 34, # 7, p. 422, Oct. 1996.
  • Martin Gardner, "The Marble and the Cork", p. 15.
  • Neil. A. Downie, "Centripetal Chaos", Ink Sandwiches, Electric Worms and 37 Other Experiments for Saturday Science, p. 134.
  • Borislaw Bilash II, “Measuring Acceleration“, A Demo A Day – A Year of Physical Science Demonstrations, p. 221.

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.