例把一支铅笔放在水杯中不同的位置,如图1所示,为什么你会看到不同的现象?解释图1B水杯和铅笔的位置俯视图如图2所示,在观察者的角度可把水杯和水看作一个整体,等效为一个凸透镜,主光轴为AB,铅笔相当于在凸 Example Put a pencil in a different position in the glass, as shown in Figure 1, why do you see different phenomena? Explain the position of the cup and the pencil in Figure 1B The top view is shown in Figure 2, from the observer's point of view Water cup and water as a whole, equivalent to a convex lens, the main optical axis AB, pencil equivalent to the convex