6A10.39 - Mirrors - Periscope

See paragraph one in the procedure section.
See paragraph two in the procedure section.
Code Number:
6A10.39
Demo Title:
Mirrors - Periscope
Condition:
Excellent
Principle:
Reflections
Area of Study:
Optics
Equipment:
Periscope demo, extra tube.
Procedure:

The periscope is adjustable in both length and orientation.  Rotating the top mirror 360 degrees will cause the image to rotate 360 degrees.

The "twirly" yard decoration has a curve in two dimensions.  This results in your reflection turning 180 degrees for every 90 degree turn of the twirly.  Or, your reflection will go around twice for every single turn of the twirly. 

References:
  • Alan J. DeWeerd and S. Eric Hill, "Reflection with a Twist: The Helical Mirror", TPT, Vol. 44, # 8, Nov. 2006, p. 496.
  • George Amann, "An Old Periscope with a New Twist", TPT, Vol. 34, # 7, p. 408-409, Oct. 1996.
  • Thomas B. Greenslade, Jr., "Photo - Polemoscope", AJP, Vol. 77, # 12, Dec. 2009, p. 1117.
  • Carson I. A. Ritchie, "Optical Toys", Making Scientific Toys, p. 17.
  • Don Rathjen, Paul Doherty, "Periscope with a Twist", Square Wheels, 2002, p. 63.
  • Charles Vivian, "Make Your Own Pressure", Science Experiments & Amusements For Children, p. 27.
  • Theresa Breen, "Early Adopter", Popular Mechanics, Feb. 2013, p. 102.
  • "Useful Periscope That a Boy Can Make", The Boy Mechanic Makes Toys, p. 84.
  • Janice VanCleave, "48, Periscope", Teaching the Fun of Physics, p. 76.
  • "Exploring Light and Sight", The Ben Franklin Book of Easy & Incredible Experiments, p. 115.
  • Brian Jones and Matt Fackelman, "Rotating Periscope", Don't Forget the Duct Tape, p. 129 - 132.
  • Bobby Mercer, "Up Periscope", Junk Drawer Physics, p. 82.
  • Tik L. Liem, "The Simple Periscope", Invitations to Science Inquiry - Supplement to 1st and 2nd Ed. p. 88.

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.