Snow Science: Coffee Filter Snowflakes
Discovery Place Science
Let it snow! Snow in our region is unique to the winter season. The colder temperatures make water droplets freeze into ice crystals. But each of these ice crystals is unique. Thanks to temperature and humidity, no two snowflakes are alike!
Today, we’re going to make our own unique snowflakes, and we won’t need freezing temperatures to do it. With this experiment, coffee filters create perfect snowflakes, or dendrites. A snow machine pumping right out of your kitchen!
Age range: Elementary and middle school
Prep time: 5-10 minutes
Learning time: 15 minutes
- Coffee filters
- Scissors (with an adult’s help)
- Glitter or crayons if you like
1. Fold your coffee filter in half.
2. Fold it in half again, and even one more time if you’d like. The more times you fold it, the more intricate it will look when it's done.
3. With your scissors and an adult’s help, carefully start cutting out small half circles or triangles on the fold and on of the edge of your coffee filter.
4. Open up your snowflake to see what you’ve created. If you need to, fold it back up and continue cutting.
5. To make your snowflake more unique, get creative by coloring it in or adding glitter.
6. Do this again with more coffee filters but with different cutout designs. How many unique snowflakes can you make?
Let it snow! Well, that begs the question…how?
Snowflakes form in a similar process to rain droplets. Temperature, of course, is the biggest differentiating factor. Clouds and raindrops form when cooled water droplets collide onto pollen or dust particles way upstairs in the atmosphere. When that droplet is extremely cold, it will also attach, but create an ice crystal instead of a water droplet.
The ice crystals have a symmetrical, even pattern because of the internal crystal structure of water molecules. This crystal structure gives the flake its six sides; temperature and humidity help determine the shape.
Temperatures just a few degrees below freezing create snowflakes with long needle-like shapes. Temperatures well below freezing (closer to 0 degrees Fahrenheit) create snowflakes with flat plate-like shapes. We call both types of shapes dendrites.
Snowflakes get their intricate arms as they fall through the atmosphere. Temperature and humidity will grow or melt the snowflake in different ways, shaping the arms.
But no two snowflakes are alike!
As snowflakes fall through the atmosphere, they each follow slightly different paths from the clouds to the ground. Therefore, every snowflake encounters slightly different temperature and humidity profiles in the atmosphere. This makes the creation process of those six arms unique to each individual snowflake!