Physics Friday
Homeschool Edition
Lake Michigan Winter Steam

This isn’t an ‘experiment’ that you can do at home, unless you live near a lake or pond and the temperature suddenly drops below freezing, but it can help you visualize a certain phenomenon of physics, so I thought I’d share.

In the video above, the temperature of the air is much colder than the temperature of the water. The water in the lake has yet to freeze. The freezing air has very little water vapor in it (that’s why it’s so dry). The lower the temperature gets, the less water vapor can stay in the air. The point at which water in it’s gas form turns into liquid water is called the dew point. This interaction between the temperature and water and the dew point is how you gets things like clouds, fog, dew on the ground, frost, etc.

See a school lesson on phase changes explained here.

As the water in Lake Michigan evaporates into the air, it freezes instantly. Water evaporates all the time, the catch is normally the water droplets are SO tiny that we can’t see them. Only in these perfect conditions can you really visualize water evaporation.

Another viral video has been going around and people have been trying it that involves instant evaporation. If you’ve seen people throwing boiling water into the air, actually what you are seeing is the majority of the hot water turning into water vapor and then the rest of it freezing.

This would be a good video to use to teach your kids about how water evaporates and turns into water vapor. Below are some links of experiments you can do with your kids to teach them about water evaporation.

Here’s a better explanation of what’s happening from National Geographic:

The water in Lake Michigan hasn’t frozen yet—it’s still relatively warm. And during typical U.S. winters, the air is warm enough that when water evaporates, you can’t view the droplets without a microscope. But in extremely cold temperatures, water vapor freezes instantly and creates ice fog, as in this video.

"In the Arctic, we call this riming," explains Uttal, whose research often takes her to the Arctic. "We get rime all over our instruments from the ice fogs."

According to Uttal, temperatures can dip so low that riming can even freeze your eyelashes together. “It’s actually why I haven’t bought a pair of metal [framed] glasses in a few years. I buy plastic ones to keep the rime from freezing the frames to my face.”

Here’s a super scientific explanation of this phenomenon called riming. - WARNING: Real Science!

See the other Physics Friday: Homeschool Edition videos here.