Snow
雪
Snow is a form of frozen water.
雪是水的固体形态，
It contains many groups of tiny ice particles called snow crystals.
是由冰结晶聚合而成的固态降水。
These crystals grow from water particles in cold clouds.
这些冰结晶来自冷云团的水粒子。
They usually grow around a piece of dust.
他们通常生长在一片灰尘周围。
All snow crystals have six sides, but they grow in different shapes.
所有的冰晶都有6个角，但却能形成不同的形状。
The shape depends mainly on the temperature and water levels in the air.
而形状主要取决于空气中的温度和水位。
Snow crystals grow in one of two designs—platelike and columnar.
冰晶有片状和柱状之分。
Platelike crystals are flat.
片状冰晶是平的。
They form when the air temperature is about fifteen degrees below zero Celsius.
当气温大约是摄氏零下十五度时候它们就会形成。
Columnar snow crystals look like sticks of ice.
柱状冰晶像是冰柱的样子。
They form when the temperature is about five degrees below zero Celsius.
它们在大约摄氏零下五度时形成。
The shape of a snow crystal may change from one form to another as the crystal passes through levels of air with different temperatures.
当冰晶穿过不同温度的空气层，可以从一种形状转化成另一种形状。
When melting snow crystals or raindrops fall through very cold air,they freeze to form small particles of ice, called sleet.
当正在融化的冰晶或是水滴穿过冷空气时，就会形成雨夹雪。