Frozen bubbles

[ColdRiverRun]

Looks like the Mount Washington Observer crew had some fun last night. Here

 

[DiamondRidge]

"nom nom"! Cute

 

[walker]

Playing Outside

Very Nice...Now I have another reason to go out and play when the temps is -10F.

I already know the trick about throwing a boiling , or nearly boiling, in the air when it's super cold out. The liquid turns from a solid to a crystal and just floats away in the wind. Very cool.

Thanks for the post....
Live Free and Hike (and stay warm).....Walker

 

[TEO]

I already know the trick about throwing a boiling , or nearly boiling, in the air when it's super cold out. The liquid turns from a solid to a crystal and just floats away in the wind. Very cool.

How is this different from simply throwing liquid water of any temp in extremely cold air, other than that it will take longer for the water to freeze?

 

[brianW]

Has to do with hot water evaporates faster.

 

[Raven]

How is this different from simply throwing liquid water of any temp in extremely cold air, other than that it will take longer for the water to freeze?

Under some conditions, hot water actually freezes at a faster rate than cooler water - it really depends on the two temperatures, the amount of water, surface area in the container, etc. It's called the Mpemba Effect. It's been repeated in experiments many times but there's disagreement as to why it occurs.

As far as forming freezing crystals from near boiling water is concerned, as Brian mentioned, evaporation is probably the key factor. When the hot drops are in the air, much of the mass of the hot water evaporates from its own heat. As it loses mass, it freezes more quickly.

If you use cold water, the individual drops don't lose mass through evaporation so the drops stay relatively "large" and "heavy" and don't crystallize.

Overall, the hot water allows the drops to become very small quickly and therefore freeze fast, something not seen with colder water.

 

[TEO]

Under some conditions, hot water actually freezes at a faster rate than cooler water - it really depends on the two temperatures, the amount of water, surface area in the container, etc. It's called the Mpemba Effect. It's been repeated in experiments many times but there's disagreement as to why it occurs.

According to this article in Science News, the Mpemba Effect hasn't been repeated in experiments many times, and whether or not it actually exists is still debatable.

An excerpt from the article: "Papers published over the last decade, including several by Auerbach, who performed his research while at the Max Planck Institute for Flow Research in Göttingen, Germany, have documented instances of hot water freezing faster than cold, but not reproducibly, says study author James Brownridge of State University of New York at Binghamton. 'No one has been able to get reproducible results on command.'" The article goes on to say that Brownridge was finally being able to repeatedly get hot water to freeze more quickly, but only when the initially hot water was from the tap and the initially cold water was distilled.

 

[TCD]

One of the possiblities that has been suggested for why this effect is SOMETIMES observed is that hot water has impurities in it which can act as "condensation nuclei" (of a sort, adopted from a different phase transition, and not necessarily valid). The results you cite would be consistent with that. Sounds like fodder for a nice, carefully conducted DOE; I'm surprised a high school or college P-Chem course has not conducted and documented it. But there's not a lot of crossover between the designed experimant folks and the science folks until you get to industry, where no one can spend time on fun stuff...

 

[Dr. Dasypodidae]

Here are two links, the first to the MWO You-tube video made at the summit on March 6th, 2007, by one of our own, Jim Salge. The MWO weather observers are always chomping at the bit for these cold-temperature opportunities, and now with You-tube, they can entertain all of us. One of the reasons that I love teaching an Edu-trip every winter on the summit is for the experience of hanging out for a couple of days with these folks. The second link provides a nice explanation for what presumably happens when boiling water is tossed into -30 F air; vapor is the key, so the water must be boiling (about 200 F on the summit). I have known Sue Kieffer since our days at Mount St. Helens in 1980; she understands bubbles from volcanic eruptions as well as anyone.

http://www.youtube.com/watch?v=PQEVcCv_xkQ

http://www.geologyinmotion.com/2011/01/boiling-water-turns-to-snow.html

 

[Raven]

According to this article in Science News, the Mpemba Effect hasn't been repeated in experiments many times, and whether or not it actually exists is still debatable.

An excerpt from the article: "Papers published over the last decade, including several by Auerbach, who performed his research while at the Max Planck Institute for Flow Research in Göttingen, Germany, have documented instances of hot water freezing faster than cold, but not reproducibly, says study author James Brownridge of State University of New York at Binghamton. 'No one has been able to get reproducible results on command.'" The article goes on to say that Brownridge was finally being able to repeatedly get hot water to freeze more quickly, but only when the initially hot water was from the tap and the initially cold water was distilled.

The effect has been observed under different circumstances. I do not mean to imply the experiment has been reproduced under the same conditions multiple times, only that it has been seen multiple times.

The nuclei idea from impurities in tap water is an interesting one; somewhat like cloud condensation. The problem I have with Browridge's explanation from a scientific perspective is that he's changing multiple variables in his experiments. Not only is he starting with water at different temps, it's from different sources (tap/distilled) with different freezing points due to the depression effect of solutes in the tap water. That's great that he can get it to work with two different water sources, but he'll need to control his variables to find a cause. In short, I don't buy it; he's comparing apples and oranges.

Another thought that comes up in this conversation is that gases are much less soluble in hot water than in cold unlike solid impurities. Whether this has an effect is still unclear as far as I know.

 

[Raven]

and regardless of the science behind it, it's absolutley beautiful to see those bubbles freeze in air. It's really amazing to see the crystallization spread across the surface. Cool.