拉脱法测量液体表面张力系数实验的研究与设备改进

Research and Improvement of Equipment for Measuring Surface Tension Coefficient of Liquid by Pull-off Method

拉脱法测量液体表面张力系数实验是大学物理实验中的一个经典实验项目。该实验采用硅压阻式力敏传感器测量力的大小,通过数显表读取力对应的电压值。但是,通过数显表只能看到液膜断裂前后瞬时拉力对应的电压值,不能看到力随位移变化的曲线,不便于直观理解力的变化过程。实验教学中,学生容易将电压极大值与液膜断裂前瞬间的电压值混淆,从而导致测量值不准确。因此,对拉脱法测液体表面张力系数的传统装置进行改进,将实验装置与计算机结合,由计算机直接采集和处理数据,提高了实验的可视化和自动化程度,便于学生理解力的变化过程,提高了实验结果的准确性。

The experiment of measuring liquid surface tension coefficient by pull-off method is a classical experiment item in university physics experiment. In this experiment,the silicon piezoresistive force sensor is used to measure the magnitude of the force,and the voltage corresponding to the force is read by a digital display meter. However,only the voltage corresponding to the instantaneous pulling force before and after the liquid film breaking can be seen by the digital display meter,and the curve of the force changing with the displacement can not be seen,which is not convenient for intuitive understanding of the changing process of the force. In the experiment teaching,students are apt to confuse the maximum voltage with the instantaneous voltage before liquid film breaking,which results in inaccurate measurement. Therefore, the traditional device for measuring liquid surface tension coefficient by pull-off method is improved. The experimental device is combined with computer to collect and process data directly by computer,which improves the degree of visualization and automation of the experiment,facilitates students'understanding of the changing process and improves the accuracy of the experimental results.