snow and rain， the air is the cooling water from the condensation， condensation is only when the degree of cold， and thus have rain， snow difference. when the air temperature is very low level， the water vapor condensation in the air， is not it condenses into water droplets， but by the water vapor condenses into direct light snow film. by the gas passing through the liquid directly into a solid condensation of this change， in meteorology， called \"sublimation”。 as a result， that snow is a special way of the formation of ice. when the clouds at the same time there is a cooling of the ice crystals and water droplets （clouds stability in the air， the temperature at -20 degrees celsius or lower， the cloud has been able to maintain the water droplets， known as the cooling water droplet）， snowflake easy to generate. cooling off the ice than water droplets evaporate easily. when the ice crystals on the evaporation of water vapor will not reach saturation， and the cooling-off drops at this point in time did not stop the evaporation， evaporation of water vapor on the surface of ice crystals in china increased by condensation， and gradually increase the volume， has become a branch of osteoporosis the small hexagonal binghua， and this is snow.
the snow is very beautiful shape， it‘s very neat pattern， the structure of the complex and diverse forms. has found there are more than 4000 kinds of different patterns. some of them like a blooming peony， plum blossom， some as thin， and some， like the separation of zhicha antlers， and some， like the glass on ice frozen. if you put them together， we can form a beautiful pattern.
雪和雨一樣，都是空氣里的水汽冷卻凝結而成的，只是凝結時天氣冷的程度不同，因而有了雨、雪的區別。當天空上層的溫度很低、空氣中的水汽凝結時，它就不是凝結成水滴，而是由水汽直接凝結成小雪片。由氣體不經過液體而直接凝結成固體的這種轉變，在氣象學上叫做“升華”。因此，可以認為雪花是經過一種特殊方式形成的冰。當雲層中同時存在著冰晶和過冷的水滴（雲層氣流穩定，溫度在—20攝氏度或更低時，雲中尚能保持的水滴，叫做過冷的水滴）時，容易生成雪花。過冷卻的水滴比冰晶容易蒸發。當冰晶上的水汽達到飽和不再蒸發時，而過冷卻的水滴在這時候並沒有停止蒸發，蒸發的水蒸氣就在冰晶的表面上升華凝結，體積逐漸增大，變成了疏鬆枝狀的六角形的小冰花，這就是雪。
雪的形狀十分美麗，它的花紋非常整齊，結構複雜，形狀多樣。已經發現的有4000多種不同的花紋。它們有的像盛開的牡丹，有的像瘦削的梅花，有的像分出枝杈的鹿角，有的像玻璃上凍結的冰花。如果把它們擺在一起，就能構成一幅美麗的圖案。