1．运用光的直线传播规律来解题例1俗话说：坐并观天，所见甚小．为什么在井底观天比在井外观天所看到的范围小呢？解析由于光在空气中是沿直线传播的，由于井口很小，所以从井底观天所看到的范围就比较小．如图回所示．除此以外，如影子的形成、日月食的成因等都可以用光的直 1. The use of light to the law of straight lines to solve the problem Example 1 As the saying goes: Sit and view the sky, you see very small. Why is the scope of the observation in the bottom of the well is smaller than the range seen in the appearance of the well? Because the light is propagating in a straight line in the air, since the wellhead is very small, the range seen from the bottom of the well is relatively small. As shown in the figure. In addition, such as the formation of shadows, the causes of eclipses, etc.