Why is the sky so blue?

The atmosphere shines directly on the ground, while the blue, purple, indigo and other colored lights with short wavelength are easily blocked by particles suspended in the air, thus scattering the light in all directions and making the sky appear blue. In fact, the scattered blue light is only a small part, and most of the blue light and purple light that have not encountered particles still hit the earth directly, so the white light that hits the earth is still red, orange, yellow, green, blue, indigo and purple. Have you noticed that the sky will become bluer after the heavy rain? The clearer the weather, the bluer the sky. This is because there are a lot of dust particles, water droplets and ice crystals in the air in such weather. The sky is red, yellow, blue, green, blue and purple! Everyone used to think that the sky was white. Later, Newton accidentally discovered that the sky was made up of red, yellow, blue, green, blue and purple. He thought, why is the sky we see white? Newton did an experiment. He cut a small triangular gap from all the red, yellow, blue, green, blue and purple cardboard, then inserted them into each other to form a circle, then poked a hole in the middle of the circle, inserted a pencil, and finally turned the pencil, and the disc also turned. To everyone's surprise, when turning, it changed from red, yellow, blue and green. That is to say, red, yellow, blue, green, cyan, blue and purple can synthesize white! So ... do it yourself! Because water reflects light, and then it is blocked by light, it is blue when reflected to human perspective. There is something wrong with your eyes! The blue of the sky is the blue part of visible light. Visible light includes seven colors: red, yellow, blue, green, cyan, blue and purple. Among them, blue light is the most easily refracted or scattered. Because the density of the atmosphere is unevenly distributed in the vertical direction in the air, visible light will be refracted when it passes through the atmosphere. Among them, the blue band refracts more than other bands, and there are many fine particles in the troposphere, that is, the low-altitude atmosphere. The blue band of visible light also scatters more than other bands because of the refraction of the first few colors in the atmosphere. Like asking me? It suddenly began to rain on the road, and I was extremely happy. Because it rains, I can feel the scenery in the rain. Because I didn't have an umbrella, I could feel the freshness of the rain hitting me. The sky in my heart is always blue. When sunlight enters the earth's atmosphere, it will be scattered by atmospheric molecules and other particles. These atmospheric molecules and particles themselves do not emit light, but because they scatter sunlight, each atmospheric molecule becomes a light source of scattered light. They shine in all directions. There are not many dust particles floating in the sky, so molecular scattering (Rayleigh scattering) is the main one, and the intensity of scattered light is inversely proportional to the fourth power of incident light wavelength. Of the seven colors contained in sunlight, purple, blue and cyan are the most easily scattered by atmospheric molecules; However, light waves with longer wavelengths, such as orange, red and yellow, have the strongest transmittance and are weak when scattered. They can penetrate these atmospheric molecules and keep their original range direction. In this way, the light waves are separated, and the scattered light at high altitude is mainly purple, blue and cyan. In addition, the color of scattered light is closely related to the size of particles. The smaller the particles are, only short light waves are scattered. For the scattering of low-level air molecules, it is mainly blue light scattering. Therefore, the sky we see is blue, and the clearer the weather, the bluer the sky. Because the earth is a blue sky.