Further Discussion on Measurement of Liquid Surface Tension Coefficient by pulling escape method

In this paper, we measured liquid surface tension coefficient of the 20 degrees' pure water by FD-NST-I liquid surface tension coefficient measuring instrument, and made further discussion of when to read the number of digital voltmeter. We divided the pulling escape process of ring leaving liquid membrane into five stages, researched on the force analysis of the metal ring and the change of digital voltmeter of each stage, and discussed mathematically of the pulling escape process of liquid membrane by contrasting analysis of the measuring experiment, and finally made the conclusion that in the measurement, it is the maximum value of the digital voltmeter in the process that the ring pulls off the liquid membrane that should be read.