Every so often, it gets so bitterly cold that you can actually go outside, throw a cup of water into the air and — instead of hearing it splash on the pavement — watch it seemingly dissolve into a cloud of snow.
Today, Portland broke a nearly five-decade-old record with a low temperature of -11 degrees.
That’s cold enough for the above magic trick, and to illustrate just how gosh darn cold it is, the Portland Police Department posted a video on its Facebook page of one of its officers doing exactly that.
At the time of this post, that police video had been viewed nearly 37,000 times over four hours, with more than 930 shares and 460 likes. Click here to see the post yourself.
Although it’s hard to tell from the police video, typically this trick is done with boiling water, which is a little counterintuitive, because the hotter the water, the further one would think it is from becoming snow.
The BDN’s own Julia Bayly made a similar video a few years back when Aroostook County was experiencing some particularly bitter cold.
Mark Seeley, a climatologist from the University of Minnesota, explained the science behind the whole “water-to-snow” trick a few years ago to the website Live Science:
“When it’s cold outside, there’s hardly any water vapor present in the air, whereas boiling water emits vapor very readily that’s why it’s steaming. When you throw the water up in the air, it breaks into much smaller droplets, so there’s even more surface for water vapor to come off of.
“Now, cold air is very dense, and this makes its capacity to hold water vapor molecules very low. There’s just fundamentally less space for the vapor molecules. So when you throw the boiling water up, suddenly the [freezing cold] air has more water vapor than it has room for. So the vapor precipitates out by clinging to microscopic particles in the air, such as sodium or calcium, and forming crystals. This is just what goes into the formation of snowflakes.You have to have a huge temperature gradient to see this effect. Here in Minnesota, we don’t try this experiment until it’s -30, but I suppose if the air is dry enough if it’s [slightly warmer] with extremely low relative humidity you can get away with it.”