1D50.40 - Central Forces - Pail of Water

Code Number:
1D50.40
Demo Title:
Central Forces - Pail of Water
Condition:
Fair
Principle:
Forces Due To Circular Motion
Area of Study:
Mechanics
Equipment:
Water pail (small, 1/2 gal. cap.), Platform and Beaker or Paper Cups.
Procedure:

Fill the small pail about 1/2 full with water and swing in a circular motion. Make sure the water does not pour out of the pail when stopping.. These same instructions apply to the platform and beaker with the added note that to hit anything (such as the instructors leg), while swinging the platform will cause the beaker to fly out tangentially in a spectacular manner.

Styrofoam pellets or confetti may be used instead of water.  

An additional twist when doing this demo is to put absorbent Pampers or absorbent crystals into the bottom of the pail before taking it into the classroom.  Pour the water into the pail in front of the students and then do the demonstration.  At the end of the demo, show the students that there is still water in the bucket by throwing it out over the audience.  Of course, by that time the absorbent material should have absorbed all of the water so there is nothing that comes out of the pail.   

References:
  • Fernando Tornaria, Martin Monteiro, Arutro C. Marti, "Understanding Coffee Spills Using a Smartphone", TPT, Vol. 52, # 8, Nov. 2014, p. 502.
  • "Figuring Physics", TPT, Vol. 50, # 7, Oct. 2012.
  • Wojciech Dindorf, "To Swing a Ball", TPT, Vol. 50, # 2, Feb. 2012, p. 121.
  • "Figuring Physics", TPT, Vol. 47, # 9, December 2009, p. 598.
  • Derek B. Swinson, "Ski Chairlift Experiments", TPT, Vol. 35, # 9, Dec. 1997, p. 528.
  • Richard A.D. Hewko,  "The Racing Car Turn",  TPT, Vol. 26, # 7, p. 436, October 1988.
  • Frank Butcher,  "Circular Motion Studies with a Toy Airplane",  TPT, Vol. 25, # 9, p. 572, December 1987.
  • Donna A. Berry,  "Circular Motion with the Soundwagon",  TPT, Vol. 25, # 9, p. 570, Dec. 1987.
  • J.W. Beams,  "High Centrifugal Fields",  TPT, Vol. 3, # 6, p. 103, Sept. 1963.
  • Mb- 29:  Freier and Anderson,  A Demo Handbook for Physics.
  • M- 354:  "Test Tube on Bike Wheel",  DICK and RAE Physics Demo Notebook.
  • M- 362:  "Water in Circle-Coin on Hanger",  DICK and RAE Physics Demo Notebook.
  • Julien Clinton Sprott, Physics Demonstrations,  "1.7, Pail of Water",  p. 19, ISBN 0-299-21580-6.
  • Swing the Bucket, The Usborne Book of Science Experiments, p. 20.
  • Borislaw Bilash II, David Maiullo, "A Real Swinger", A Demo a Day: A Year of Physics Demonstrations, p. 130.
  • Robert Ehrlich,  "Whirling a Water-Filled Can in a Vertical Circle",  Turning the World Inside Out, p. 76- 77.
  • "Water Whirled in a Circle", Physics From the Junk Drawer, 3rd Edition, The Science House, North Carolina State University, p. 23.

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.