论文部分内容阅读
同学们在晚自习时，坐在灯的前后或两边的同学由于光线斜射到书本上，稍加注意就可以看到握笔的手在纸面上留下的影子．仔细观察纸面上笔或手的影子，我们会发现影的边缘部分比影的中心部分相对地亮一些，好像影子的周围还有一圈虚的边界似的．物理学上把影的中部最黑暗的区域
When the students were studying in the evening, students sitting in front of or behind the lamp and leaning on the books due to the light, they could see the shadow of the hand holding the pen on the paper. When we look closely at the shadow of a pen or hand on the paper, we will find that the edge of the shadow is relatively brighter than the central part of the shadow, as if there is a virtual border around the shadow. The darkest area in the middle of physics