6A10.39 - Mirrors - Periscope
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.
- 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.
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