Measuring the thermal expansion of solids with strain gages

A technique was developed to measure the thermal expansion of solids in the temperature range from -50 to 175 C. The technique uses strain gages to measure expansion and Type J (iron/constantan) thermocouples to measure temperature. Measurements were made on pure platinum and on copper and tungsten standard reference materials. Results were compared with the certified values of expansion. The maximum difference between measurements made in this study and the certified values was 0.26 times 10 to the minus 6/deg C for the mean coefficients and 0.40 times 10 to the minus 6/deg C for the instantaneous coefficients. The standard deviation of the measurements of the mean coefficients was 0.11 times 10 to the minus 6/deg C.