1, the reason why snowflakes are hexagonal:
Snowflake is a kind of tiny crystal with complex structure. Every snowflake in nature is unique, but they all have a hexagonal structure. Due to the different pressure and temperature when falling, the internal structure will be different.
Snowflakes are condensed by water molecules in the atmosphere. Because oxygen atom has SP3 electron orbital structure, oxygen atom and two hydrogen atoms use four electrons, leaving two isolated electrons. Lone pair has a greater repulsive effect on oxygen-hydrogen bonds, which makes water molecules have no symmetrical structure, so water molecules are polar molecules.
Surprisingly, this asymmetric water molecule forms a symmetrical hexagonal crystal instead. Hexagons have six-fold rotational symmetry, which is mathematically called continuous symmetry. The study of continuous symmetry was perfected by the Norwegian mathematician Sosos Lee, so we call this group Lie Group.
Physicists can better understand continuous symmetric crystals by studying Lie groups. Snowflake, a two-sided symmetric structure, is an operation set that satisfies closure, association law, identity and inverse transformation.
2. Snow and ice sports:
When the snowflakes are flying, there is a place in the northeast that is in full swing, and that is the ski resort in the northeast. Northeast skiing is a game with a long history, from skating in the yard when I was a child, to the creaking of ice on the river ditch near the school, and the ice car playing with children in the park. It seems that the winter of the northeast people can't be separated from ice and snow.
Skiing has become a mass fitness program in Northeast China, and the most important thing is that it is suitable for all ages! In addition to skiing, there are snow banana boats with snowflakes flying; Passionate and exciting snow off-road vehicle; Playing and chasing ice bikes; Children's favorite snow mini electric car ..... is very lively and fun.
3. Snow blindness
Snow blindness refers to the situation that people's eyes are temporarily lost sight when they are in an environment with too high and concentrated sunlight intensity for a long time and are reflected by ice and snow on the ground or ice crystals in clouds. Suffering from snow blindness, I felt quite sensitive at first, then I blinked all the time, accompanied by strabismus, and then my eyes would be pink, gradually deepening, and there was a grinding pain.
Extended data:
Anti-freezing tips in winter:
First, walk more and soak your feet.
Cold comes from feet, and feet are the focus of winter health care. Exercise more, let your feet move and promote blood flow; Soak your feet with about 40% hot water before going to bed every day, so that the yang will rise and the whole body will be smooth, which is conducive to sleep; After soaking your feet, massage Yongquan point on your left foot 36 times with your right hand and Yongquan point on your right foot 36 times with your left hand. This can effectively prevent colds.
Second, insist on winter sports.
Half an hour in winter is because the climate is cold, but the colder it is, the more you should exercise, because exercise is the best way to drive away the cold, and it can also enhance the disease resistance and reduce the occurrence of diseases. For winter sports, you can choose jogging, cycling and playing Tai Ji Chuan. And you can also choose indoor fitness places, such as aerobics, table tennis, bowling and so on. However, when the elderly exercise, they must do what they can, and they can't choose sports with too much activity and too much exercise.
Third, hold your nose and exhale to prevent dryness.
Cold and dry air can increase the secretion of respiratory mucosa, hinder gas exchange and concentrate respiratory pressure. Wear scarves and masks when going out in winter, and drink warm water at ordinary times to prevent the respiratory tract from being too dry; After 9 o'clock in the morning, you should open the window at home, or you can cook vinegar at home for sterilization.