Abstract: In the experiment of measuring the Youngs modulus of metal wire using the optical lever method, it is necessary to calculate the small angle of rotation of the optical lever system by measuring the distance from the optical lever axis to the scale and the change in the scale reading. In this paper, a sensor for measuring the slope angle in the mobile phones Phyphox software is used to directly measure the small angle of rotation of the phone, thereby obtaining the small elongation of the metal wire. The relative error of measuring the Youngs modulus of the metal wire using this method is only 0.5%. Through wireless networks, mobile phones and computers can be interconnected, and experimental data can be displayed in real-time in the form of charts on the computer desktop, making the experimental process more intuitive.

Key words: optical lever, Youngs modulus, small angle, Phyphox