雨止天晴,天空中常出现一道美丽的彩虹,那是一条弧形的由红、橙、黄、绿、蓝、靛、紫七种颜色组成的光带。当你仔细观察时便可看到,在虹的上面还有一条颜色较淡的相似的光带,它就叫霓。在古代,我国的古人就很注意观察自然现象,记下了不少关于虹的科学原理。比如当早晨西方出现 It is sunny and rainy, and a beautiful rainbow often appears in the sky. It is an arc of light that consists of seven colors: red, orange, yellow, green, blue, black and purple. When you look closely, you can see that there is a lighter similar band of light above the rainbow. It is called neon. In ancient times, the ancients of our country paid great attention to the observation of natural phenomena, and recorded many scientific principles about the rainbow. For example, when the west appeared in the morning