Why do snowflakes need six petals?

The scenery is beautiful when it snows, but scientists and artists appreciate the exquisite snowflake patterns. Glaciologists began to describe the shape of snowflakes in detail more than a hundred years ago. Ding Duoer, the originator of western glaciology, described the snowflakes he saw on Loza Peak with vivid and beautiful brushstrokes in his classic glaciology works. These snowflakes ... are all made up of small ice flowers. Each small ice flower has six petals. Some petals release folli's small lateral tongue like Su Hua, some are round, some are arrow-shaped, or serrated, some are complete, and some are lattice-shaped, but they are not beyond the scope of six petals. Tindor's conclusion is correct. All snowflakes are six petals. It was our people who found six petals of snowflakes. As early as BC 100, in the era of Emperor Wendi of the Western Han Dynasty, there was a poet named Han Ying, who wrote A Biography of Chinese Poetry, which clearly pointed out that "there are six snowflakes everywhere." Two years ago, I pointed out that snowflakes are hexagonal, which is really not simple. In Europe, it was not until l6 1 1 that the German astronomer Kepler recorded that snowflakes were hexagonal, which was 1700 years later than China. The basic shape of snowflakes is hexagonal. However, it is strange that two identical snowflakes can hardly be found in nature, just as two identical people can't be found on earth. Many scholars have observed thousands of snowflakes with microscopes. These studies finally show that it is impossible to form snowflakes with the same shape and size and partial symmetry in nature. Among these observed snowflakes, even the regularly symmetrical snowflakes are deformed. Why do snowflakes have the shape of batteries? Because the water vapor content in the atmosphere around snowflakes can't be the same in all directions, as long as there is a slight difference, the side with more water vapor content always grows fast.

There are many collectors of snowflake patterns in the world. They collect all kinds of snowflake photos like stamp collectors. An American named Bentley took nearly 6 photos of Zhang Qian in his life. Soviet photographer Siger Mountain is also a photographer of snowflake photos. His charming works are often used as models of structural patterns by artists. The most famous scientist who collects snowflake photos is Nakaya Ukichiro. He and his colleagues worked hard for 20 years to photograph and study tens of thousands of snowflakes in the cold room of the laboratory of Hokkaido University in Japan and in the tent on the snowfield in northern Japan. Later, he published a monograph entitled Snow Crystal-Nature and Artificiality in England. In this scientific book, which is correct in science, excellent in art and full of fantasy, we introduce more than two photos of snowflakes in Zhang Qian.

However, although snowflakes have various shapes, they remain unchanged, so scientists may classify them into the seven shapes mentioned above. Among these seven shapes, hexagonal snowflake and hexagonal prism snowflake are the most basic forms of snowflake, and the other five are only the development, transformation or combination of these two basic forms.

Why are the basic shapes of snowflakes hexagonal and columnar?

This is related to the crystallization habit of water. Ice frozen by natural water and snow crystallized by water vapor in the atmosphere belong to hexagonal system. Hexagonal crystal system has four crystal axes-a major axis and three minor axes. The three auxiliary axes are distributed on the same plane and intersect symmetrically at an angle of 60 degrees. The main crystal axis comes from the intersection of three auxiliary axes, and the well is perpendicular to the plane formed by the auxiliary axes. The most typical representative of hexagonal system is like a regular hexagonal cylinder in geometry. When water vapor condenses and crystallizes, if the main crystal axis develops slower and shorter than the other three auxiliary crystal axes, the shape of snow becomes hexagonal snowflake; If the main crystal axis develops quickly and extends long, the shape of snow becomes a hexagonal prism. The temperature in the atmosphere plays a great role in the shape of snowflakes. High temperature is easy to produce hexagonal snowflakes, and low temperature is easy to produce columnar snowflakes. According to the observation and research of many scientists, when the atmospheric temperature is lower than -25℃, the shape of snow is mostly hexagonal prism with main crystal axis; When the temperature is -25℃ ~- 15℃, the crystals of snow are mostly hexagonal. When the temperature is-15℃ ~ 0℃, most beautiful hexagonal snowflakes fall in the sky.

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