There are two kinds of precipitation: one is liquid precipitation, which is rain; The other is solid precipitation, which is snow or hail.

Rain is liquid and snow is solid.

2. Different types

Snowflakes, star-shaped snowflakes, columnar snowflakes, needle-shaped snowflakes, multi-branched snowflakes, axial snowflakes and irregular snowflakes.

There are many kinds of rain, besides acid rain and colorful rain, there are frog rain, iron rain, golden rain and even modesty.

3. Different principles

There are two conditions for the formation of snowfall:

One condition of (1) is water vapor saturation. The maximum amount of water vapor that air can hold at a certain temperature is called saturated water vapor. The temperature at which air reaches saturation is called dew point. When saturated air is cooled to a temperature below the dew point, the excess water vapor in the air becomes water droplets or ice crystals.

(2) Another condition is that there must be condensation nuclei in the air. If there is no condensation nucleus, the water vapor in the air will condense into water droplets only if it is supersaturated to the degree of relative humidity above 500%.

When it rains, the water vapor in the cloud can be continuously replenished and replenished, so that the surface of cloud droplets is often in a state of supersaturation. Then, this condensation process will continue, making the cloud droplets bigger and become raindrops.

When the cloud drops increase to a certain extent, due to the increasing volume and weight of large cloud drops, they can not only catch up with the slower small cloud drops, but also "swallow" more small cloud drops, making themselves stronger. When the big cloud drops get bigger and bigger until the air can no longer hold them, they fall straight from the clouds to the ground and become our common rain.

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