We love, love, love it when lots of snow falls and we get a day off from school. Then we can go sledding, build snowmen, etc. But at some point, the snow melts away. Our fan Cadence asked, how long does that take? Well, it turns out there are 2 grown-up ways to use math to figure that out. One compares all the heat coming in and out: heat from the sun, heat from the ground below, and heat lost to the cold air. The other way compares the temperature that day and 32 degrees F, which is the freezing point. Every day is different, but as a rule of thumb, in 40-degree weather we lose half an inch of snow per day. 50-degree weather melts 2 to 4 inches a day! Let’s hope it stays cold for our sledding and snowmen.
Wee ones: A snowflake has 6 sides. Can you hold up 6 fingers?
Little kids: If there are 3 inches of snow on the ground and 1 inch melts today, how many inches are left tonight? Bonus: If it snows 1 inch each hour from 2:00 in the morning until 6:00 in the morning, how many inches of snow did you get?
Big kids: If there are 10 inches of snow on the ground, how many more inches of snow need to fall for it to reach the top of your head? Bonus: If that snow melts away 2 inches every day, how many days until it’s all gone?
Answers:
Wee ones: Count to make sure you have 6 fingers up: 1, 2, 3, 4, 5, 6.
Little kids: 2 inches. Bonus: 4 inches, since it snows for 4 hours.
Big kids: Different for everyone…find your height in inches, and subtract 10. Bonus: Again, different for everyone: take your height in inches of snow, and divide by 2 to find how many 2s need to melt away.

Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking before she could walk, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.