In order to measure coefficients of thermal expansion of small samples varying from one to twenty millimeters in thickness an optical lever has been designed to allow detection of a change in thickness of the sample of plus or minus twenty Angstrom units. The dilatation is read in terms of the change of interference bands produced between two nearly parallel glass plates. A formula was developed which does away with continuous observation during the expansion. Through the use of this formula the accuracy of the result is comparable with that obtained by continuous observation. The samples do not have to be ground to a specified size, nor do they have to be optically flat. Adjustment of the sample in the apparatus requires about fifteen minutes.
Proceedings of the Iowa Academy of Science
©1933 Iowa Academy of Science, Inc.
Gorham, John E. and Higgins, George C.
"Determination of Linear Coefficients of Thermal Expansion of Thin Samples by Optical Lever,"
Proceedings of the Iowa Academy of Science, 40(1), 154-155.
Available at: https://scholarworks.uni.edu/pias/vol40/iss1/85