There are many classroom demonstrations, such as the ball-and-ring experiment, for showing the existence of thermal expansion of solids. The coefficient of linear expansion α (= increase in length divided by the original length times the change in temperature) may be measured in high school laboratories using a number of methods.1–4 In this paper we describe an especially simple experiment for determining α for a metal rod. It is based on the well-known optical lever method and is suitable for either a laboratory experiment or a classroom exercise.

1.
http://store.pasco.com/pascostore/showdetl.cfm?&DID=9&Product_ID=55467&Detail=1.
2.
R.
Mostert
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Classroom experiments on thermal expansion of solids
,”
Phys. Teach.
30
,
15
(Jan.
1992
).
3.
R.
Trumper
and
M.
Gelben
, “
Measurement of a thermal expansion coefficient
,”
Phys. Teach.
35
,
437
438
(Oct.
1997
).
4.
http://www.sargentwelch.com/info.asp?ii=386.
5.
James S. Walker, Physics, 3rd ed.(Pearson Prentice Hall, Upper Saddle River, NJ, 2007), p. 521.
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