We have all seen beautiful snowflakes. If we put snowflakes under a magnifying glass, we can find that each snowflake is an extremely exquisite pattern, which even the artists admire. So, how do all kinds of snowflakes form?
Snowflakes, large and small, are actually grown from ice crystals. In the cloud, when water droplets collide with ice crystals, they will adsorb on the surface of ice crystals and make it increase rapidly. When the small ice crystal increases to overcome the resistance and buoyancy of the air, it falls to the ground, which is snowflake.
Ice crystals have two main shapes. One is hexagonal, long and thin, called columnar crystal (if it is as thin as a needle, it is also called needle crystal); The other is hexagonal flake shape, which is called lamellar crystal. As the name suggests, ice crystal is a kind of crystal, that is, it has certain symmetry like diamond crystal. Scientists used X-ray diffraction to study and found that ice crystals belong to hexagonal crystals.
Ice crystals in the atmosphere are generally produced by water vapor condensation, with a very symmetrical shape. The temperature and humidity of the environment are different, resulting in different symmetrical shapes. When environmental factors change, the formation mode of ice crystals will also change, so the final ice crystals may be a mixture of multiple styles. For example, if there is more water vapor around the ice crystal and the six corners grow rapidly, it will form a star; If there is little water vapor around the ice crystal and the six corners do not grow as fast as the two bottoms, it will form a column; If the water vapor is moderate, it will form flakes.
After all kinds of ice crystals are formed in the sky, when their diameter reaches a certain size (more than 50 microns), they can overcome the buoyancy of the air and begin to fall, and continue to grow and change while falling. In this way, snowflakes of various shapes are produced.
Scholars have observed two snowflakes in the same shape with a microscope, but the results are basically the same. At present, more than 4000 different kinds of snowflakes have been recorded. Moreover, there is no snowflake with completely symmetrical parts in nature. Among these snowflakes that have been observed by people, the regular and symmetrical snowflakes also have deformities.