As anyone in town for NCTM in Denver know, it’s been a bit snowy here this week. In fact, Fort Collins just had its biggest snowfall of the year. But how big?

We had a two hour school delay this morning as my daughter and I were greeted by this on our back doorstep.


“Wow that’s a lot of snow!” she says. But how much snow is it?  Go go gadget EmergentMath!


I got this ridiculously large [cola] mug at a white elephant gift exchange last Christmas. And now I have a chance to use it!


I asked her to make a prediction on how full the mug would be after it melted. We each made a prediction using her hair ties (hers on top, mine on bottom).


We took a couple measurements just for posterity’s sake.



I dunno, we might want them later. For now though, we just stuck with the predictions.

We then watched it melt. Slowly.

Sure enough, we were both way off:

013 015

Wow. All that snow and only that much actual moisture. I have some questions:

  • Is this typical? What if we redid this in the afternoon after the snow had packed a little more? 
  • What if we used different shapes? Could this be a sort of alternative to the how-full-is-the-weirdly-shaped-glass problem?
  • Going back to the original photo, how much water was on that table?

I also have a couple comments:

  • Want an easy way to build buy in? Have kids make predictions on something and make sure it *takes a long time* for them to see if they’re right. Like I said, our delay was a couple hours and this pretty much took up the entire time. This was sort of analogous to Dan Meyer’s now-famous water tank filling task.
  • This seems ripe for Estimations 180.
  • I’m not sure what you could do if you live in a non-snow state. What would Texas use? Sand? Cicadas?

My daughter and I could have gone into the volume of the near-cylinder, which dimensions were useful and that sort of thing. But our two hours were up. It was time to go to school.

Update 4/16: I’ve got my Facebook friends eating out of the palm of my hand. *maniacal laugh*



Sort of related: a couple atmospheric scientist friends of mine started a Facebook page crowdsourcing, archiving, displaying, and discussing clouds: Community Cloud Atlas 

You should join their Facebook page and tell them to get a twitter account.

8 thoughts on “What? How do YOU spend your two-hour school delays?, Water Content in a Snow Cylinder

  1. Too much fun. Just bonkers. Coming out of sunny CA, I haven’t given a lot of thought to phase changes of water except for liquid to gas so this whole thing hit a fun nerve for me.

    1. Ha! Enjoy it while you’re in town, Dan. Be sure to get all your snow-related Act 1’s while you’re here!

      Snow is great because 1) it melts in an “appropriate” amount of time and 2) the water content changes considerably from each snowstorm & season.

  2. My wife once told me that “An inch of rain equals a foot of snow.” Also, their is a saying that 1 inch of rain is 10 inches of snow. I wonder if your evidence supports either saying. It might be an interesting thing to ask kids.

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