3B20.70 - Crova's Disc

Place the assembly on the overhead projector and focus the slot in the assembly onto the wall.  Rotate the disc and the image of the lines as viewed through the slot should take the appearance of either standing or longitudinal waves.
Code Number:
3B20.70
Demo Title:
Crova's Disc
Condition:
Good
Principle:
Wave Motion
Area of Study:
Acoustics
Equipment:
Overhead Crova's disk assembly
Procedure:

Place the assembly on the overhead projector and focus the slot in the assembly onto the wall.  Rotate the disc and the image of the lines as viewed through the slot should take the appearance of either standing or longitudinal waves.

References:
  • Randall D. Peters,  "Traveling Wave Pedagogy Using an Oscilloscope",  TPT,  Vol. 28, # 5, p. 337, May 1990.
  • S. D. Cloud, "Oscilloscope Traveling Wave Experiment", TPT, Vol. 23, # 3, Mar. 1985, p. 157 - 158.
  • R. D. Edge, "An Op Art Wave Demonstration", TPT, Vol. 8, # 9, Dec. 1970, p. 521.
  • A. D. Bulman, "Sound-Wave Representation--Crova's and Cheshire's Disks", Model-Making for Physics, p. 66.
  • 5.04:  R.D. Edge, "Longitudinal Waves - Crova's Disc", American Association of Physics Teachers.

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.