The first snow falls of winter is a time of celebration as the kids eagerly pile layers and layers of clothes on to head out and explore! Living in the snowbelt of Ontario means we have no shortage of snow days. Grab your favorite mittens and cozy tuque for an adventure as we discover the science of snow with our free snowflake unit study and activities!

Why does it snow?

Snow is part of our world’s water cycle. The sun’s heat causes water to evaporate from our oceans, lakes, or rivers into water vapor that rises up into the sky. The higher it goes, the colder it gets. This water vapor starts to change back into tiny water droplets or ice crystals that come together as clouds (condensation). Snowflakes form when it’s cold enough for water vapor to freeze onto a microscopic particle of pollen or dust floating in the sky. These snowflakes are very small but grow as more water vapor freezes onto that first ice crystal. It gets bigger, and bigger, until it gets so heavy it starts to fall to the ground (precipitation). When the weather is warmer, the snow melts and flows back into the water system (collection) and the cycle begins again! (Some water vapor is also released into the water cycle through plants in a process called transpiration and through sublimation where ice or snow directly converts into a gas instead of becoming a liquid first.)

Why do snowflakes come in different shapes and sizes?

Every snowflake starts out as a tiny hexagon ice crystal. Why is it six-sided instead of four or eight? That’s because when water molecules (made up of two hydrogen atoms and one oxygen) bond and freeze together with other water molecules, they arrange themselves in a lattice of hexagonal rings. As our little ice crystal falls to the Earth, it’s exposed to different temperatures and humidity conditions along the way. It’ll pick up more water vapor and dust that will freeze onto our first ice crystal and branch from each of its six corners. Snowflakes that grow in warmer temperatures grow slower, creating more flat and lacy plates. But, if it then travels through a colder gust of wind, we’ll start seeing thin plates, hollow columns, and needle shapes emerge. Since no two snowflakes travel through the exact same path and conditions on their way down, no two snowflakes are the same shape or size! If it starts to get warmer closer to the ground, many snowflakes might start melting and sticking together to form larger flakes.

Why does it snow more on one side of a mountain?

Have you ever wondered why it often snows more on one side of the mountain than the other? In winter cold winds from the sea bring clouds that hit the mountain and begin to rise over top. The farther away you get from the Earth’s surface, the colder it gets. The lower pressure up on the mountain top just isn’t very good at holding onto all that heat. When the air is near sea level, the air pressure squishes it into a smaller space. But up on the mountain the air pressure is lower. Now that same air and all its heat is spread out over a bigger space. It thins out pretty quickly and it gets very, very cold. As the clouds rise up over the mountain, these frigid conditions cool the floating water vapor making it snow. Most of the snow is gone before the clouds travel to the other side. With all that moisture now gone, it stops snowing and the clouds disappear.

Activity: Art Appreciation

Spend some time studying this wonderful color wood block print by Takahashi Hiroaki (Japan, 1871-1945) titled Foot of Mount Ashitaka , and appreciate the snowy peaks in the background. Download a jpg. of this print for study from the LACMA collections here. Then try asking these questions:

What is this artwork about?
What was your reaction when you first saw it?
Which area of the print do you think the artist is emphasizing? Why?
How would you describe this print to a friend who hasn’t seen it?
Why do you think the artist created this?
What do you think this print says about Japanese culture?
What does this print make your think of or remind you of?
If you had to create a story to go with this picture, what would it be?

FREE Snow Cycle Poster and Worksheet

Join the list at the end of this post to visit our subscriber page and download your FREE Snow Cycle Poster and Worksheets. If you’re already a subscriber, find this activity on our community page (check your most recent Newsletter for the link).

A Thing Called Snow Family Literature and Activity Guide

This is just one of the many activities in our A Thing Called Snow Family Literature and Activity Guide. Join Fox and Hare as we learn about the science of SNOW. Learn about the different types of snow fall, what makes snow look white, why it feels cold, what makes snow fluffy or sparkle? Discover how the Arctic Hare and Arctic Fox have adapted to life in the frozen tundra. You’ll find Nature Studies, STEM activities, crafting, cooking together, and more! Our read aloud, A Thing Called Snow by Yuval Zommer, will have us playing with snowy adjectives and narrating with our Arctic friends story puppets.