Abstract: The measurement of liquid surface tension is a fundamental experiment for physics undergraduates. However, due to the large systematic error, increasing the experimental accuracy and precision has always been a persistent challenge in this project. We propose an improvement to the device by incorporating micrometer lifting platform and spiral height regulator based on the pull-off method. These modification enable a better control over the liquid membrane as well as a measurement of its height during detachment which is a critical parameter for evaluating the operational stability. In addition, the liquid membrane gravity was considered and its influence on experimental results is investigated quantitatively by applying metal rings with identical mean diameters but different wall thickness, thereby the accuracy of liquid surface tension coefficient measurements has been enhanced effectively.

Key words: surface tension coefficient, liquid membrane gravity, pull-off method