6J11.10 - Retinal Fatigue - Bidwell's Disc

Code Number:
6J11.10
Demo Title:
Retinal Fatigue - Bidwell's Disc
Condition:
Good
Principle:
Fatigue and After Images
Area of Study:
Optics, Human Biology
Equipment:
Variable Speed DC Motor, Compact Fluorescent Bulb with Red Jell, Half White Half Black Disc with a Section Cut Out, and 100 Watt Light Bulb in Desk Lamp.
Procedure:

Put the red bulb behind the cutout.  If the disc is spun so that you see the red bulb and then the white section of the disc the bulb will appear green.  If it is spun so that you see the red bulb and the black section of the disc the bulb remains red.

References:
  • G. D. Freier and F. J. Anderson, "Oi-12", A Demonstration Handbook for Physics.
  • Richard Manliffe Sutton, "L-94. Complementary Colors Produced Subjectively", Demonstration Experiments in Physics.
  • Raymond Bruman, "Color Reversal", Exploratorium Cookbook I, p. 29.1 - 29.2.
  • Shoma Kutasov, "Bragg's Experiment", Physics Demonstrations, p. 273.
  • R.D. Edge, "13.01", String & Sticky Tape Experiments, p. 2.
  • Brian Jones and Matt Fackelman, "Red to Green", Don't Forget the Duct Tape, p. 117 - 120.
  • Robert J. Brown, "A Mystery Color Wheel", 200 Illustrated Science Experiments for Children, p. 81.

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.