When most materials are heated they expand.1 This concept is usually demonstrated using some type of mechanical measurement of the linear expansion of a metal rod.2 We have developed an alternative laboratory method for measuring thermal expansion by using a Michelson interferometer. Using the method presented, interference, interferometry, and the principle of thermal expansion can be taught concurrently. The material is accessible to undergraduates and advanced high school physics students.

Topics
Interferometry, Thermal effects, Education, Laboratories
1.
R.A. Serway and J.W. Jewett, Physics for Scientists and Engineers, 6th ed. (Thomson, Belmont, CA, 2004), p. 587.
2.
See http://class.phys.psu.edu/213labs/ and click on “Thermal Expansion” in the left column to download the procedure for a laboratory experiment to measure thermal expansion by mechanical means.
3.
Ref. 1, p. 1194.
4.
E. Hecht, Optics, 4th ed. (Addison-Wesley, San Francisco, 2002), pp. 407–410.
5.
While α actually varies with temperature, it remains essentially constant for minor temperature changes.
6.
CRC Handbook of Chemistry and Physics, 86th ed., edited by D.R. Lide (Taylor & Francis, Boca Raton, 2005), pp. 12–196.
7.
Thermophysical Properties of Matter, Volume 12. Thermal Expansion, Metallic Elements and Alloys, edited by Y.S. Touloukian (IFI/Plenum, New York, 1975), p. 76.
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© 2009 American Association of Physics Teachers.
2009
American Association of Physics Teachers
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