Watch the video below, find some place freezing cold, then get ready to do some science:
The thermodynamics going on here is pretty straight forward. To make ice fog you need to fulfill three basic conditions: scalding hot water, frigid outdoor temperatures, and a decent throwing arm.
First, the water. The amount of steam that will be made boiling water is proportional to the temperature of the water — the hotter the water, the larger fraction of it becomes steam.
Next, the cold. When it’s absolutely freezing outside (the video above claims the air temperature is -30 degrees Fahrenheit or -34 degrees Celsius) the air can’t hold as much water vapor inside it. So when a bunch of steam is chucked into this cold air, millions of tiny water droplets rapidly condense out of it.
Finally, a decent throw. The more steam and water that is exposed to the air — the more surface area that the freezing temperatures have to work with — the more that can freeze before it hits the ground. Surface area is the same reason why granulated sugar, rather than a sugar cube, mixes faster into your morning coffee.
To recap: Get some water as hot as possible, take it into the arctic outdoors, and give it a strong, wide toss into the air. You’ve just made ice fog!
This article is adapted from an earlier post at Scientific American.