6J11.42 - Mach's Bands

See paragraph one in the procedure section.
Code Number:
Demo Title:
Mach's Bands
Eye Perception
Area of Study:
Optics, Human Biology
Mach Band disks, small DC motor, 0 to 20 volt power supply.

Place and tighten the desired pattern disk onto the motor shaft.  Adjust the voltage on the power supply until the black or white bands that shouldn't be present are indeed clearly visible.

  • Richard Held, "Contour and Contrast", Scientific American, May 1974, p. 17.
  • R. W. Pohl, "(c) Mach's Bands", Physical Principles of Mechanics and Acoustics, p. 3.

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.