平行板电容器是一种重要的电容器 ,高中《物理》第二册教材中通过一个演示实验来研究决定它的电容大小的因素 ,虽然本实验的现象明显 ,但学生并没有真正理解其中的一些道理 .笔者根据多年来的教学经验认为 ,非常有必要给学生讲清一些必要的问题 ,以加深他们对实验原理的理解 .? The parallel plate capacitor is an important capacitor. In the second volume of the textbook “Physics” in high school, a demonstration experiment was used to study the factors determining its capacitance. Although the phenomenon of this experiment was obvious, students did not really understand some of them. Based on years of teaching experience, the author believes that it is very necessary for students to clarify some necessary issues in order to deepen their understanding of experimental principles.