The weather forcast has us with some super cold weather (-30 with wind) coming tonight, and I’ve seen a trick on YouTube where someone takes a pan of boiling water, tosses it into the frigid air and POOF, it turns to “snow”. First off, is this true, can this really be done, and secondly if so, what’s the science behind it? I’d love to show this off to the nephews tonight to keep my Mr. Wizard credentials up to date.
A lot of the effect you are seeing is due to water vapor rapidly condensing. So the lots of white stuff you see may not really be snow (it could be), but it is the “essence of cloud”
You see the steam coming off of the pan before he throws it. The dropletts of water thrown in the air give off steam in the same way. THeres a lot of those drops and there’s high surface area, which equals lots of steam.
I grew up in Minneapolis and one night on the news, the weather guy had a Styrofoam cup of hot water that he threw into the air and it looked like it turned into powdered ice that fell to the ground like sand. Sorry for no science, but an eyewitness account might help.
In extreme cold, it absolutely works. I can only offer my own experience as a cite, but at -60, water does not make it to the ground as a liquid.
I do not think the entire mass of water in that video “turns to snow”. I think a lot of steam forms a cloud (rather than snow) and the rest of water falls to the ground, unseen in the video, more or less frozen, depending. In reality all you need to “make snow” is a pulverizer bottle. That’s how the snow making machines in ski resorts work.
What is a pulverizer bottle? Google only comes up with machines for pulverizing glass.
Just to throw in the obligatory nitpick, you’ve never seen steam. Steam is gaseous water, and is invisible. What you see rising off of a pot of boiling water is tiny droplets of condensed liquid water suspended in the invisible steam (such droplets are also what you’re seeing when you look at a cloud). If you look closely at the spout of a boiling teakettle, you’ll notice that the cloud you’re seeing doesn’t start until a centimeter or two above the spout: Below that point, the steam is still too hot for visible droplets to condense out of it.
The number I’ve seen for this type of trick is -25 F. Friends have tossed pans of water in the air and it was all frozen or evaporated by the time it hit the ground.
Other neat tricks:
Leave a banana and an orange sitting out for a while. You will be able to drive nails with the banana once it’s frozen. The orange will shatter like glass when you chuck it at the ground.
I checked the forecast for your area, which predicted -13F, with wind chills to or below -30. The wind chill is the combined effect of temperature and wind on exposed skin. The result of tossing water into the air will be much the same as at -13 with no wind – IOW, not much.
My sources say it works at around -50F and below. (I tried it once, at -40 - the water froze soon after hitting the ground, but not in the air.)
There’s not much to the science beyond the fact that if you get water cold enough, it freezes.
Note that snowmaking machines, through various forms of cleverness, achieve a similar effect at much higher temperatures.
Oh cool, I have both bananas and oranges that are hovering around their use by dates so I can totally do this too.
Oh, bummer.
Yeah, I went back and forth with adding a disclaimer in my post above about the difference between steam and condensed water droplets you see. I opted to go with the ordinary lay persons understanding and leave out the disclaimer…figured I’d lose either way.
Sorry. I meant a spray bottle which pulverizes water into a fine mist.
I think sailor must have meant atomizer.
OW! I just smashed my thumb with a frozen banana!
What sort of “minimum temperature” does this require to demonstrate? It’s due to get near 0F here in the next day or two, as the low temperature, and this would be fun to try prior to leaving for work…
The main reason I read the SDMB is to learn stuff like this. Thanks! I will consume a neuron (or at least a dendrite) for the underlying pearl.
Still, it does seem like the word “steam” also applies to the visible mist when water vapor condenses in the air. There’s no chance you are mixing up “steam” and “water vapor” is there? If I’m gonna be pedantic I gotta get it right. Nothing as painful as a counter-correction.
Colder then that. I’ve never tried it at less then -20.
From here: Steam - Wikipedia
when it gets that cold, go blow some soap bubbles.
They freeze and are much more rigid and they rise further because of the relatively warm air they are filled with. Also when they break they don’t really disappear, the soap film stays together and plummets to earth.