Surface Tension - Floating Metals

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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.

Condition :   Excellent   
Principle :   Surface Tension 
Area of Study :  Heat & Fluids  
Equipment :   Evaporating dish, toothpicks, dishwashing soap, razor-blade, paperclips, needles.

Procedure :   Carefully place the metal objects in the water so that they float.  Place a drop of liquid soap on a toothpick and touch to the surface of the water.  The metal objects should sink as the surface tension is reduced or broken.
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Letters to the Editor, "Quick Way to Float a Paper Clip on Water", TPT, Vol. 46, # 2, Feb. 2008, p. 70.

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John W. M. Bush, David L. Hu, "Walking on Water", Physics Today, June 2010, p. 62.


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Charles Vivian, "Testing the Skin of Water", Science Experiments & Amusements For Children, p. 20.

Pat Murphy, Ellen Macaulay, and the staff of the Exploratorium, "Sink or Swim", Exploratopia, p. 108.

Martin Gardner, "Two 10-Cent Betchas", Science Tricks, p. 10.

Martin Gardner, "17, A Floating Coin", Smart Science Tricks, p. 30.

F- 330:  "Sieve Bucket - Float Needle",  DICK and RAE Physics Demo Notebook.

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W. Bolton, "Wetting Agents", Book I - Properties of Materials, Physics Experiments and Projects, 1968, p. 22.

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