10 Dec STEM Challenge – How Do Snowflakes Form?
We are focusing on Antarctica this month. Antarctica is the coldest continent on Earth, which means it has a lot of ice and snow! This week we are going to explore how snowflakes form and build our own snowflakes.
Visit our blog every Thursday to see our latest STEM challenge and share your creations on social media using #CMMSSTEMChallenge or by emailing firstname.lastname@example.org. Be sure to submit your photos to us by Monday, December 14!
- White paper
- Colored foam sheets or construction paper
- Snowflakes start out as round or spherical, water droplets in the clouds. When the temperature is cold enough, the water droplets freeze and take on a hexagonal shape. Start by cutting out a few hexagons from the white paper. You might remember that a hexagon is a simple 6 sided shape – like a stop sign. The hexagons are our starting point for making snowflakes.
- As the crystallized water droplet falls through the freezing cold air, it attracts water vapor. The water vapor attaches to each of the 6 sides of the hexagon – creating the branches or little arms we see on snowflakes. Now, cut a piece of white paper into a pile of 1″ x 1/4″ pieces of paper. These will be the water droplets that attach themselves to the hexagon.
- As the snowflake falls to the ground and picks up more and more water vapor, it grows. Creating a snowflake is as simple as adding on more and more water vapor to create a symmetrical pattern. You can cut your pieces of paper even smaller as you branch further out from the first hexagon so that you can vary the shape of the snowflake. The reason no two snowflakes are ever exactly alike is because each snowflake takes a different path through the air, spinning and bumping into different numbers of the water vapor branches…pretty cool, right?
- Once you have created your snowflakes they can be glued in place on the foam sheet or construction paper. You can also choose not to glue your snowflake and instead keep experimenting with different creations to build different snowflake shapes.
Why are snowflakes symmetrical when they form?
The symmetry of a snowflake has to do with crystallization – the process where solids are formed into a highly structured and organized crystal. Put simply, the shape and size of the initial hexagon that formed from the water droplet will determine the branch formation of the snowflake. The formation of the snowflake is crystallization. As the water molecules form the growing branch structures, they take up the amount of space that is provided by the hexagon. Think of reaching out your fingers beside someone else. You don’t want to bump into their fingers, or you might hurt your finger. So you reach out your fingers to just the right distance to take up the space that is available. Now imagine your arm was attached to a hexagon base and your arms reached out from the points of the hexagon – this is how the snowflake reaches out and keeps growing. You can see when creating your snowflake how science can be quite organized and orderly – this is the case of snowflake formation (or crystallization).
When Do Snowflakes Form?
Snowflakes can only form when the temperature reaches 0°C – the freezing point of water molecules. That doesn’t mean that it will always snow when it is 0°C, since there are other atmospheric conditions that have to be met to guarantee there will be snow, such as humidity, moisture, wind, etc. But at the very least, it has to be cold enough for the water droplets to form into ice crystals to start growing into a snowflake. You can think about that scientific process the next time it’s very cold outside and you are wishing for snow!