Diffraction - Hair and Pins

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 Code Number :   6C20.20  



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.

Condition :   Good  
Principle :   Edge Diffraction
Area of Study :  Optics, Astronomy   
Equipment :   Helium-neon laser (2 to 5 mw.), Optics bench, Tape measure (25 ft.), hair stretched on a 35mm slide holder, Styrofoam block with pins and washers.

Procedure :   Screw the diffusing lens onto the laser and place either the hair, pins, or washers into the diffused beam.  A shadow of the object should appear on the screen with multiple bright and dark outlines.
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Thomas B. Greenslade, Jr., "Diffraction by a Cat's Whisker", TPT, Vol. 38, Oct. 2000, p. 422.

Robert P. Bauman, "Diffraction and Non-Diffraction Fringes", TPT, Vol.  34, # 6, p. 339, Sept. 1996.

G.R. Davies, "Interference and Diffraction Corridor Demonstrations", TPT, Vol.  33, # 4, p.  244 - 247, April 1995.

Walter Scheider,  "Bringing One of the Great Moments of Science to the Classroom",  TPT, Vol. 24, # 4, p.  217, April 1986.

Robert Barrett, Kenneth Lodge, Martha Schreffler, "Photographing Diffraction Patterns Without a Camera", TPT, Vol. 16, # 3, Mar. 1978, p. 180.

R. C. Nicklin and J. Dinkins, "Laser Diffraction Photography", TPT, Vol. 12, # 5, May 1974, p. 295.


Salvatore Ganci, "Fraunhofer Diffraction by a Thin Wire and Babinet's Principle", AJP, Vol. 73, # 1, Jan. 2005, p. 83.

S. M. Curry, A. L. Echalow, "Measuring the Diameter of a Hair by Diffraction", AJP, Vol. 42, # 5, May 1974, p. 412.


O-530:  "Needle, Slit, and Razor Blade",  DICK and RAE Physics Demo Notebook.

O-532: "Human Hair Diameter with Laser",  DICK and RAE Physics Demo Notebook.


T. Kallard, "Measuring the Diameter of a Hair by Diffraction", Exploring Laser Light, p. 202.

"Historical Note on "White-Light Interference Fringes"", Apparatus Notes, July 1965-December 1972, p. 51.

"Photographing Diffraction Effects", Apparatus Notes, July 1965-December 1972, p. 33.

Yaakov Kraftmakher, "4.2, Diffraction of Light", Experiments and Demonstrations in Physics, ISBN 981-256-602-3, p. 227.

3.15:  Charles Taylor,  The Art and Science of Lecture Demonstration, p. 149-150.

T. D. Rossing, C. J. Chiaverina, "5.6, Diffraction", Light Science, Physics and Visual Arts, p. 113.

 Roman Ya. Kerzerashvili, "Abstract: Advanced Optics with Laser Pointer and Metersticks", 2005 Apparatus Competition, Salt Lake City, UT. 

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