6A42.40 - Refraction - Penny & Cup

See paragraph one in the procedure section
Code Number:
6A42.40
Demo Title:
Refraction - Penny & Cup
Condition:
Excellent
Principle:
Refraction of Light Waves
Area of Study:
Optics
Equipment:
Styrofoam cup, penny, water.
Procedure:

 Place the cup on the bench with the penny inside and towards one side of the cup.  Look into the cup and slowly back away until the penny is no longer visible.  Without moving your eyes from their position, pour water into the cup and notice that the penny reappears when the cup is full of water.

References:
  • Od-4:  Freier and Anderson,  A Demonstration Handbook for Physics.
  • Charles Vivian, "Penny in a Bowl", Science Experiments & Amusements For Children, p. 74.
  • Martin Gardner, "57, The Vanishing Coin", Smart Science Tricks, p. 88.
  • Martin Gardner, "Vanishing Postage Stamp", Entertaining Science Experiments with Everyday Objects, p. 75.
  • Vicki Cobb and Kathy Darling, "Odds That Are Out of Sight", Bet You Can't!, p. 95.
  • "The Coin-in-the-Cup Experiment", The Boy Scientist, p. 181.
  • Janice VanCleave, "35, Where's the Penny?", Teaching the Fun of Physics, p. 57.
  • Tik Liem,  "The Reappearing Coin", Investigation to Science Inquiry, p. 277.
  • Tik Liem, "11.13, Why Do We See Two Coins?", Investigation to Science Inquiry, p. 283.

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.