The science of snowflakes: See how they form and why no two are ever alike
Snow is made up of trillions of tiny ice crystals that make snowflakes, with not one alike. Here's how they form.
Snow. It's made up of tiny ice crystals that can transform into a variety of intricate symmetrical patterns forming a beautiful snowflake. Have you ever wondered how snowflakes form?
Did you know snowflakes that reach the ground are often combinations of ice crystals? These crystals take on a variety of shapes that are determined by the temperature in the clouds where they form, but the basic shape is a hexagon, due to the bonding of hydrogen and oxygen molecules in the air.
How a snowflake is born
The diagram below, which is based on a chart created by Japanese physicist Ukichiro Nakaya, illustrates how atmospheric temperature and humidity can impact the growth of ice crystals into snowflakes. Once a snow crystal becomes a prism, it can go in one of two major directions: either a plate or a column.
Although higher humidity at warmer temperatures tends to produce the amazing snowflakes we see every winter, scientists are still unsure of how temperature influences this result.
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The unique steps an ice crystal takes to form a snowflake
According to the National Oceanic and Atmospheric Administration, an incredibly cold droplet of water freezes onto a dust or pollen particle in the sky to produce a snowflake. As a result, an ice crystal forms. Water vapor freezes onto the original ice crystal as it falls to the earth, creating additional crystals known as the six-armed snowflake.
Are there a snowflakes coming near you?
Why are there no two snowflakes alike?
Each snowflake travels a slightly different path as it descends to the earth. Since each snowflake can come in contact with varying atmospheric conditions on its route, each snowflake will have its own appearance start to develop, which can resemble a simple prism or a lacy pattern.
How many snowflakes fall each winter worldwide each year? The number of snow crystals that fall from the sky each winter is an estimated 1 septillion (that's 1,000,000,000,000,000,000,000,000 – which is about a trillion trillion), according to the Library of Congress.
That's a lot of very unique snowflakes!
This story was updated to add new information.