在初中物理课本第二册“透镜”一节中,对凸透镜使光线会聚及凹透镜使光线发散,只是通过如图1和图2简单地做了说明,有条件的学校也只是通过演示实验给学生以感性认识。这样学生只能机械地识记,而对其会聚和发散的原因并不清楚。这样在实际问题的处理上有时就会产生错误,如图3和图4,在立方体形的玻璃块中,分别有一个凹 In the “lens” section of Physics Book 2 of the junior middle school, the convex lens causes the light to converge and the concave lens causes the light to diverge. This is simply illustrated by Figure 1 and Figure 2. The conditional school also gives students a demonstration experiment. With perceptual knowledge. In this way, students can only memorize mechanically, and the reason for their convergence and divergence is not clear. This can sometimes lead to errors in the handling of practical problems, as shown in Figs. 3 and 4, in a cube-shaped glass block, respectively.