The electrical design of the common hair dryer is based almost entirely on relatively simple principles learned in introductory physics classes. Just as biology students dissect a frog to see the principles of anatomy in action, physics students can “dissect” a hair dryer to see how principles of electricity are used in a real system. They can discover how engineers solve problems such as how to vary between low and high heat and fan speed by simply moving the position of a single switch. Principles of alternating versus direct current, series and parallel circuits, electrical safety, voltage dividing, ac rectification, power, and measurement of resistance and continuity all come in to play.

Topics
Bioacoustics of amphibians, Parallel circuits, Educational aids
1.
The online appendix can be viewed at PHTEAH-46-009809.
http://ftp.aip.org/cgi-bin/epaps?ID=PHTEAH-46-009809). For more information on EPAPS, see http://www.aip.org/pubservs/epaps.html.
2.
Ann Meeker-O'Connell, “How hair dryers work,” at howstuffworks: http://home.howstuffworks.com/hair-dryer.htm., p. 4.
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© 2008 American Association of Physics Teachers.
2008
American Association of Physics Teachers

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