Music: 0a 0b 1a
Video: /
Reading: Tsing hua infant English
Mother learning: Online parent courses
Hail is formed in the flow cloud, when the water vapor rises with the air, it condenses into small water droplets. If the temperature continues to decrease as the height increases to below zero degrees Celsius, the water droplets condenses into ice particles. In the process of rising motion, the water droplets will grow up with small ice particles or water droplets around them until their weight does not rise. When the airflow is carried, the surface will melt into a higher temperature area, and the surface will melt into water, and it also adsorbs small water droplets around it. At this time, the surface of the strong rising air is then lifted, and its surface is condensed into ice, so that the volume of its body is more and more heavy until it is heavier than it is. The sum of the air lift and the buoyancy of the air, that is, descends down, and if the ground does not melt into the water, the solid ice particles are called hail, and the melting into water is the rain we usually see. Hailstones, like rain and snow, fell from clouds. But hailstone clouds are a very powerful cumulonimbus, and only the cumbersome cumulonimbus can cause hail. The formation of hail requires the following conditions: (1) there must be a considerable thickness of unstable layer in the short time hail. 2. Cumulonimbus must develop to the height of freezing large individual droplets (generally considered to be -12 to -16 degrees Celsius). There should be strong wind shear. (4) the vertical thickness of the cloud should not be less than 6~8 km. The water content in the cumulating cloud is abundant. It is generally 3~8 grams per cubic meter, and there is a cumulative zone of liquid supercooling water above the maximum rising speed. There should be an inclined, strong and uneven ascending air in the cloud, usually at 10~20 M / s.
