本文利用光的干涉原理和单缝衍射原理设计杨氏模量实验仪，根据光的干涉和衍射条纹的变化规律测量金属丝受拉力作用下的微小长度变化量，进而实现金属丝杨氏模量的高精度测量. 为了满足光的干涉实验条件，采用气动拉力调节装置代替砝码，解决了仪器的晃动问题，并实现了拉力改变的无级调节和电子秤拉力直读，把传统的测量杨氏模量实验由一个单纯的力学实验变成了一个力学与光学相结合的综合性实验，丰富了实验内容，拓宽了学生的视野，提高了学生分析问题和解决问题的综合能力.

A Young’s modulus experimental instrument is designed based on the principles of light interference and single-slit diffraction. According to the change rule of fringes of light interference and diffraction, the tiny length change of metal wire under tension can be measured, and then the high precision measurement of Young’s modulus of metal wire is realized. To satisfy the experimental conditions for interference of light, a pneumatic tension adjusting device is designed to replace weights, in which the shaking problem of the instrument is solved and the stepless adjustment of tension change and the reading of tension directly from the electronic scale are realized. The instrument also make a simple traditional mechanical experiment change into a comprehensive experiment combining mechanics and optics for measuring Young’s modulus, which enriches the experimental content, broadens the students’ vision, and improves their comprehensive ability to analyze and solve problems.