“用油膜法估测分子的大小”是中学物理实验中唯一通过测量宏观量求出微观量的实验,对于提高学生对微观世界的认识非常重要。但由于诸多因素的制约会影响实验的成功率。本文结合我们的教学实践,谈谈影响此实验成功率的几个因素。 “The use of oil film method to estimate the size of molecules” is the only experiment in the middle school physics experiment to determine the microscopic quantity by measuring the macroscopic quantity. It is very important to improve students’ understanding of the microcosm. However, due to the constraints of many factors will affect the success rate of the experiment. This article, combined with our teaching practice, talks about several factors that affect the success rate of this experiment.