Snow is one of interesting phenomenon when winter comes. Snow become interesting because the ice crystals are so soft and white like cotton. Snow just fall in countries that has four seasons or in high place like Jayawijaya mountain in Papua, Indonesia.

    Snow begins from water vapor that gathered in the Earth's atmosphere. A bunch of water vapor then cools to the point of condensation (the point at which the gas turns into liquid or solid form), then coagulates and form clouds. At the beginning of forming the clouds, its mass is smaller than the mass of the air, so the clouds float in the air. But, once the water vapor continue to gathered in the clouds, its mass also increases. So, at some point the air can no longer hold its mass. Then, the clouds broke and the water particles fall to the earth.

    The water particles that fall is pure water (not contaminated by other particles). The pure water doesn't freeze directly at the 0 degree of Celcius, to make the pure water freeze required lower temperature than 0 degree of Celcius. However, low temperature doesn't enough to form snow. The particles of pure water need to contaminate with other particles in the air that will make the freezing process faster. Then, the pure water will turn into ice crystals.

    The contaminated particles that involve In this process called nucleator, not only has function to make the freezing process faster but also to tied the water vapor. So, the water particles (contaminated one) that gathered with the other water particles will form bigger ice crystals. These ice crystals that fall to earth which we call snow. Snow has a unique structure because there is no snow crystal that has the same shape, just like our fingerprint.

{Source: https://www.tutorialbahasainggris.com/contoh-explanation-text-tentang-salju-snow.html)

What is the main idea of the second paragraph?