free download PNG images :Snowflakes

Snowflakes can be either individual ice crystals or a collection of ice crystals that fall through the earth's atmosphere like snow. Each sheet is nucleated around dust particles in supersaturated air masses by attracting supercooled cloud like water droplets, which freeze and accumulate as crystals. Because of the complex shape of flakes when they pass through different temperature and humidity areas in the atmosphere, each snowflake will be different in details, but it can be divided into eight categories and at least 80 individual variants. The main component shapes of ice crystals are needle, column, plate and fog, which can be combined. Although snowflakes are made of transparent ice, they still look white. This is due to the diffuse reflection of the whole spectrum from the small crystal face.

After snowflakes fall and accumulate, they will deteriorate with the change of temperature and gather into snowdrift. The characteristics of snow reflect the changing properties of snow crystals.

Snowflakes nucleate around mineral or organic particles in moisture saturated sub frozen air masses. They grow as primary crystals in the form of hexagons through net accretion. Cohesion is mainly electrostatic.