With the cold weather across much of the U.S. this winter, many of you have probably seen the videos of people tossing hot water through very cold air and watching it never reach the ground. Here's one example:
Hot Water in Cold Air
For most of these videos there's nothing incorrect about what's happening, but many details are left out. For starters, why is hot water needed? If you use cold water or don't heat the water to near boiling, the water will simply go up and then fall back to the ground. One thing that happens with hot water is evaporation. Some, although not all, of the water evaporates. Thus what is left is a lower volume of water.
Second, why doesn't the water freeze into an ice cube? And again, why is hot water necessary? Shouldn't this work better with cold water since cold water is closer to the freezing point? The properties of hot water are slightly different than that of cold water. Hot water is less "sticky". I realize this isn't the best term to use, but by less "sticky" I mean that hot water more easily breaks up into tiny droplets, whereas cold water tends to stay in a larger clump. When the water is in a larger clump, it doesn't have time to freeze before striking the ground. Hot water, however, does break up into tiny droplets. Each droplet is of very low volume and freezes into a snow like substance, thus producing the cloud you see in all of the videos.
So again, it's not as if the videos are incorrect in what they say, they just aren't telling the whole story.
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