Abstract: The traditional method for measuring the linear expansion of metals usually involves using an FD-
LEA type linear expansion coefficient tester in combination with a dial indicator．However，due to the fact that
the response rate of the instrument to temperature is higher than that of the dial indicator to deformation，the
measurement results have relatively large errors． This experiment improved the traditional instrument by
replacing the dial indicator with a self-built Michelson interference device and conducted measurements based
on the principle of optical interference．After the improvement the relative error score of the linear expansion
coefficient of the copper rod decreased from 10．77% to 4．61%，and accordingly the uncertainty also decreased
from 0．41 × 10－6℃－1 to 0．18 × 10－6℃－1，achieving a significant improvement in measurement accuracy． In
addition，the surface of the copper rods was ground and polished in this experiment，further reducing the
relative measurement error to 1．20%．The above experimental results show that the use of optical interferometry
can significantly improve the measurement accuracy of the linear expansion coefficient of metals，and at the
same time，surface treatment can eliminate the negative impact of surface oxidation of metal rods． This
experiment not only presents a highly precise device for measuring the linear expansion coefficient of metals，
but also provides a useful reference for its high-precision measurement．
曹文杰, 姜 好, 杨双艳, 庞绵忆, 汪梓超, 曾佳美, 刘海强, 张 喻 . 基于光干涉的金属线膨胀系数测量[J]. 大学物理实验, 2026, 39(2): 20-24.
CAO Wenjie, JIANG Hao, YANG Shuangyan, PANG Mianyi, WANG Zichao, ZENG Jiamei, LIU Haiqiang, ZHANG Yu . Measurement of the Coefficient of Linear Expansion of Metals Based on Optical Interference#br#. Physical Experiment of College, 2026, 39(2): 20-24.
