Last week, Arctic air parked itself over the Rockies, and on many mornings, temperatures were as cold as -35 C. That’s not so fun for skiing and snowshoeing, but it’s perfect for trying a neat winter experiment – turning boiling hot water into frozen steam in just a couple of seconds.
Here’s how it works. You fill a thermos with boiling water, and then, making sure you’re not facing the wind, you throw the hot water into the cold. Amazingly, none of it makes it to the ground as liquid water. Instead, it appears to turn into an instant cloud of frozen steam.
So, what is going on here?
Boiling water, being so close to steam, is very energetic, so when you throw it out of the thermos, it splits or breaks into tiny droplets. The droplets now have a large surface area compared to their size, which allows for a lot of evaporation. Each teensy hot droplet is trying to turn into steam.
But the air is really cold, and cold air simply can’t hold very much water vapour, so the freshly made steam condenses back into a liquid. But each bit of “condensate” is still really small, and in the cold, all those little bits quickly freeze. Once that happens, you get an ice cloud that is, literally, very cool!
Check out this video of the whole thing in action. From emptying the thermos to the ice cloud disappearing takes about ten seconds!
Thanks to Mistaya Lodge (a great place to go backcountry skiing!) for a few thermoses of boiling water and the great sunrise venue for the experiment. And thanks to Mark Finlay for exposing his fingers long enough to take the pictures and the video.
Boiling water wasn’t the only thing to freeze last week. It was cold enough that your breath and even your runny nose would freeze, especially for a bearded guy like me.
In case you’re worried, we’re back to normal temperatures this week, so it’s safe to get back out on the snowshoes and enjoy the outdoors.