Demonstrations

Diffraction - Hair and Pins

Code Number :	6C20.20
Disclaimer:	Reprinted by permission of Dick Berg, University of Maryland, for use on this website. The demonstrations contained and referenced herein are listed for the purposes of cataloging and describing physics demonstrations which should be conducted only under the direction of a trained instructional support professional or physicist. These demonstrations are not presented for the purpose of being conducted by persons unconnected to this Facility and/or persons not consulting with or being supervised by the recognized instructional support professional or physicist and his/her staff. The University is responsible only for those demonstrations carried out using its own equipment using established safety and scheduling policies, and bears no responsibility for those choosing to use this source material for their own purposes. All demonstrations described and contained herein are public domain, and can also be found in reference materials in libraries, bookstores, and electronic sources. Further information regarding legal liability in use of demonstrations and labs will be found on the web site Injuries in School/College Laboratories in USA. The University of Iowa Disclaimers: University of Iowa Disclaimer All Rights Reserved..
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.

References

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.

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.

Mail Questions and Comments to: Dale Stille