唐代诗人王之涣曾写过一首诗:白日依山尽,黄河入海流。欲穷千里目,更上一层楼。这首诗描述了光学方面的两个重要现象:第一,太阳光是白色的;第二,站得高才能看得远。当然,一千多年前的人是无法对这两种现象作出解释的,但是随着科学技术的发展,人们对光的认识逐步深入,这两种现象也就容易理解了。 The Tang Dynasty poet Wang Zhiyu once wrote a poem: It is done by mountains in the day and the Yellow River flows into the sea. For a thousand miles, go one step further. This poem describes two important phenomena in optics: first, the sunlight is white; second, standing tall can be seen far. Of course, one thousand years ago, people could not explain these two phenomena, but with the development of science and technology, people’s understanding of light gradually deepened, and these two phenomena are also easy to understand.