在阳光下或灯光下,按照图中的方法,用两只手做出各种姿态,你会看到, 墙上映出了狗、鸭、飞鸟等等的生动形象。从上面试验的图形可以看出：影子和物体的形状是相似的。那么请你想一想：影子是怎样形成的呢,为什么影子和物体的形状总是相似的? 我们学过光的现象,知道影子是由光的性质决定的,因为光的波长十分的小, 所以在遇到一般的障碍物时不会发生衍射 Under the sun or light, according to the method shown in the figure, with two hands to make a variety of gestures, you will see, the wall reflects the vivid image of dogs, ducks, birds and so on. As can be seen from the above experimental plot, the shape of the shadow and the object are similar. Then think about it: How do shadows form, why are the shapes of shadows and objects always similar? We learned the phenomenon of light, knowing that shadows are determined by the nature of light, because the wavelength of light is very small, Therefore, diffraction does not occur when encountering ordinary obstacles.