by Dante Centuori
Is your family ready to make a snowman or have a snowball fight? Teach your kids about the best time to play in this snowy weather with a science lesson.
Pack it In
You know it as soon as you touch it — the perfect “packing snow.” It has that “stick together” feeling that immediately makes you want to start stacking up snowmen or building an impenetrable snow fort. But what makes that kind of snow stick? And can you anticipate if the next snowfall will be just right for packing?
The main thing that makes snow pack into a snowball is the amount of moisture in the snow. Not the water that comes from melting snow, but the humidity in the air between the snowflakes. More moisture in the air means more water to help “glue” the flakes together. However, too much gives you slush. So you can expect good packing snow to come when temperatures are close to freezing, or 32 degrees.
It’s possible to be too cold for packing snow. There may still be moisture in the air, but when the temps get down into the mid- to low-20s, the ice crystals that form at those temperatures do not create the classic branching snowflakes we know so well, but flakes that look more like tiny needles or plates, and have less surface area for sticking. This makes it harder for powdery snow to stick, and your snowball falls apart.
Just remember, when planning for your next snowball fight, snow fort construction or snowman gallery, it’s not just the cold, but the humidity!
Make Your Own Ice Snowman
If Mother Nature isn’t cooperating, you can make your own “snowman” out of ice using some balloons and your freezer.
What you’ll need:
- Several balloons
- Various sized bowls
- A freezer
What to do:
- Start by making several water balloons of various sizes. You want their relative sizes to be like what you would want for a snowman’s body parts.
- Leave a little air at the tip of the balloon near where you’ll tie the knot; don’t overfill it with water!
- To help the balloons keep a round shape on the bottom, place in round bowls in the freezer and place them so the knot points straight up.
- When frozen, remove the rubber balloon covering by just cutting it and pulling off
- If needed, flatten one side with a cheese grater or file.
- To help stick the body segments together, moisten a small square of paper towel, felt or other absorbent cloth with warm water and place between the ice balls (The tongue-on-flagpole effect will stick them together).
- You can use the same method to stick pieces of felt, cloth or construction paper on the ice-snowman to decorate.
- Other things to try:
- What would happen if you put food coloring in the water balloon?
- Can you put items in the balloon that would float or sink so that they freeze where you want them? Like to place the buttons?
- If you have room in your freezer, try freezing the balloons by suspending them instead of sitting in a bowl. What shape will you get?
Dante Centuori is the director of creative productions at the Great Lakes Science Center. You often can see him leading the Big Science Show or blowing up fruitcakes in front of the building for special occasions. Visit greatscience.com.