Prisms
棱镜
Why can we see rainbows after rain?
我们雨后为什么能看到彩虹?
We can see rainbows after rain because droplets of moisture in the air work like a big prism.
这是因为空气中的水滴就像一个大棱镜。
So what is a prism?
那么什么是棱镜呢?
It is a piece of glass. It usually has a triangular shape.
它是一块玻璃,通常有三角。
What does the prism do?
棱镜的作用是什么?
It reflects and separates light.
它能反射和分散光线。
When we look at sunlight, it seems white.
我们看阳光时,它似乎是白色的。
However, if you see sunlight through a prism,
但如果你透过棱镜看到阳光的话,
you'll know that there are different colours from red to violet in the white light, just like a rainbow.
你就会知道,白光中有不同的颜色,从红到紫,就像彩虹一样。
Because of prisms, we know that sunlight is a mixture of different colours.
因为棱镜,我们知道太阳光是不同颜色的混合物。