Why do snow often fall on Christmas?

Christmas is a time when temperatures in many parts of the Earth are low, combined with cold air and steam, often snowing.

Snow is a precipitate of ice crystals under the atmospheric pressure of the Earth. Winter temperatures are low, in countries with snow, the ground temperature often falls below 0 degrees Celsius, the temperature in the clouds is extremely cold.

The higher the air floor, the lower the temperature, the water vapor in the clouds directly binds into small snowflakes, when these snowflakes get heavier and heavier, the air circulation cannot 'pull' and falling to the ground creates a phenomenon of snowfall. If there is a relatively strong flow of air circulating in this airflow, the snowflakes get bigger when falling to the ground. Usually snowflakes are produced in the coldest part of the cloud.

Thus, snow forms from tiny droplets of water that form matter particles. Unlike rain created by small molecules of water with low temperature forming rain drops, ice crystals form at lower temperatures, forming ice instantly and forming snowflakes. When heavy enough will fall to the ground.

The lower the temperature of the cloud, the better the ice particles are formed. Usually ice particles have a needle shape, cylindrical or sheet shape . but no matter which shape the snowflake always has 6 limbs.

Do you wonder why snowflakes are hexagonal? A snowflake has a basic structure from many embryos. Each embryo is made up of 5 molecules of water together. In particular, four molecules are located in the four corners of the tetrahedron, while the fifth molecule is in the center. A snowflake consists of many embryos that line up together. Each circle is a water molecule. The top of this tetrahedron connects to the bottom of the other tetrahedron to form a hexagon in the texture of the snowflake.

However, if it is simply a combination of embryos in a calm state, then there must be symmetrical snowflakes. Scientists say that when flying in the air, snowflake itself always rotates around its own axis, so it is very symmetrical and keeps the hexagonal shape during the movement.

Popular shapes of snowflakes are star-shaped, prismatic and mixed.

Temperatures above 0 degrees Celsius certainly do not have snow, but even though the weather is very cold, can go below 0 degrees C without dry air, you can not admire the beauty of snowflakes.

Snow only falls when there is a certain amount of water in the air, when it is not too cold (a few days before snowfall, the sky is often cloudy). The cooler the air is, the less the sky retains less moisture because most of the steam has condensed or sublimated into rain or snow at higher temperatures, so there is not enough water to condense into snow. In addition, in order to get snow, certain low temperatures are below -10 degrees Celsius, above the clouds will begin to appear snow crystals, they combine to form snow falling to the ground.

The reason why white snowflakes are simply understood is that when the sun's rays penetrate a snow particle, it will quickly be scattered by countless ice crystals and inner airbags. Nearly all of the light rays are bounced back and out of the snow, so the snow maintains the color of the sunlight as white.

Why is snow melting colder when snow falls? The reason is quite understandable that during the process of snow melting, a lot of heat is absorbed, so the air becomes colder. Conversely, when snow or ice water, water and snow release some heat to the outside. Therefore, we feel the weather becomes warmer than before. In fact, the feeling of heat or cold is mainly determined by the human body radiating heat or absorbing heat. When the snow melts, it needs to absorb a large amount of heat, the air immediately cools, the human body is cooled by air. In other words, when the snow absorbs the heat from the air, the air gets the heat from the people, the person naturally feels cold. Conversely, when snow falls, even when snow freezes, water will emit heat, the air will not be too cold.

According to scientists, 1g of ice melts into water at 0 degrees C and needs to absorb 334.4 microns (80kcal) of heat, so when a large area of ​​snow melts, the heat required to absorb must be equivalent.

Why does snow fall so much while the Earth is warming up? In fact, the Earth is warming up doesn't mean that everything on it is the same. Water exists on Earth in all three different forms: liquid, solid and vapor. According to the normal cycle of water, ocean water evaporates, condensing into clouds, clouds will create rain and rain will seep into the ground and flow into rivers and seas. As the temperature rises, the water in the rivers, seas and oceans will evaporate more and we will have more clouds, resulting in more rain and snow in some places. Therefore, global warming is also one of the fundamental causes of today's 'heavy' floods.