The twinkling stars we see in the night sky are actually huge gas fireballs burning like the sun, which emit light in all directions in outer space billions of kilometers away. Light must pass through different air layers of the earth's atmosphere to be seen by us, and light waves emitted from the edge of the beam must pass through air with different thicknesses. This causes the irregularity of light waves when they reach the ground, which makes us feel that the stars are shaking.
Why do popsicles get angry in summer? There is a lot of water vapor in the air, and the temperature of popsicles is very low. When the water vapor in the air meets the ice-cold popsicle, it will liquefy into small water droplets. The water drops are so small that we look like popsicles? . Air is a mixture of many gases. Its constant components are oxygen, nitrogen and rare gases such as argon, neon, helium, krypton and xenon. The components are carbon dioxide and water vapor, and their contents in the air will change slightly within a very limited range with the position and temperature on the earth. As for the uncertain components in the air, it varies from region to region. For example, there will be sulfur dioxide near the metallurgical plant, chlorine gas near the chlor-alkali plant and so on. In addition, there are traces of hydrogen, ozone, nitrous oxide, methane and more or less dust in the air. ?
Generally speaking, the composition of air is relatively fixed. This is very important for the survival of human beings and other animals and plants. However, with the development of modern industry, harmful gases and smog discharged into the air have changed the composition of the air and caused air pollution. Polluted air will seriously damage human health, affect crop growth, and cause damage to natural resources and buildings. ?
Harmful substances discharged into the air can be roughly divided into dust and gas. Globally, sulfur dioxide, carbon monoxide and nitrogen dioxide are the most common gas pollutants discharged into the air. These gases mainly come from the combustion of fossil fuels (coal and oil) and the waste gas from factories.
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