天空为什么是蓝色的(Why is the sky blue).doc
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天空为什么是蓝色的(Why is the sky blue)
Blue sky, white clouds floating.. Im sure everyone feels about this beautiful view. So why is the sky blue? Why is the cloud white? For this wonderful physical phenomenon, not everyone can tell the reason. In fact, the beautiful view we see is the result of the interaction of atmospheric molecules, water droplets, other particles and sunlight in the sky.
First, the air and the sun
In order to explain this physical phenomenon, we first have a brief knowledge of air and sunlight. The air is a layer of bullet proof clothing wrapped up outside the earth, protecting the earth from ultraviolet radiation. Air is not empty. It is made up of many particles. 99% of them are nitrogen and oxygen, while the rest are other gases (such as carbon dioxide, inert gas, etc.), small droplets, dust from factories, blowing sand in the wind, and lava particles from volcanic eruptions. But the composition of the air is not fixed, depending on where it is located, the weather and other factors that are not fixed (such as forests, oceans, volcanic eruptions, and pollution).
Light is a way in which energy travels in electromagnetic waves and travels at a speed of 300 thousand kilometers per second in vacuum. Light and other waves (such as acoustic) is different with the wave particle like two. This is because light consists of a massless particle - photon, so that light has not only the properties of waves, but also the properties of particles. The magnitude of the light transfer energy is proportional to the frequency of light, while the frequency of light determines its color. But our eyes can only see light within a certain frequency range, called visible light, too high frequency (ultraviolet light) and too low (infrared), and we cant see it.
For the sun, Newton was first identified with three prisms, including red, orange, yellow, green, blue, indigo and violet in 7 colors. You can observe the colorful sunlight with a small experiment (shown in Figure 1). T
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