An extremely cold question

[Artisi]

I know there are some great minds here in the pub and there are also some who live in these awful below freezing climates, so lets see who can come up with an answer to this.

http://www.sootoday.com/content/news/full_story.asp?StoryNumber=50683

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[IRstuff]

A similar thing occurs at boiling point. Many people have gotten injured with microwaved hot beverages that instantly boiled over upon being disturbed after microwaving.

TTFN
faq731-376

 

[patprimmer]

The liquid is at or just past its normal phase change point and a shock or disturbance that changes the pressure at certain points in the liquid triggers the change.

Regards
Pat
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[Artisi]

I've have experienced that when you pop the cap off a bottle of beer that's been in the freezer - change of pressure, but in a sealed bottle ????

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[waross]

One difference between water and ice is a lot of BTUs. If the BTUs are already gone you have ice. It's hard to imagine that many BTUs leaving instantly. And water bottles left in the truck in Western Canada freeze solid at temperatures much above -20.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[patprimmer]

Shere in the liquid as the water moves does cause short term local changes in pressure due to acceleration and inertia. Same as causes cavitation in a pump.

Once a few ice crystals form, it acts as a nucleating agent, just like scratching the bottom of the beaker with a super saturated salt solution.

Regards
Pat
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[JJPellin]

I first saw this when I was a teenager. At the time, they didn't sell plastic bottles of water. But I would take a jar of water with me when I traveled. I came out one cold morning to finish unloading my car. I picked up the jar of liquid water and was surprised it was still liquid. I shook it to verify it was still liquid and it froze solid in front of my eyes.

Sub-cooling is the equivalent of super-heating in a micro-wave as mentioned above. The water has to be very pure and the container has to be very clean. If there is even a speck of dust, it will nucleate an ice crystal and freeze.

They did a segment on this on Myth-Busters. They used beer rather than water.


Johnny Pellin

 

[ivymike]

Corona (beer) does this for me every Tuesday and Thursday when I finish my workout. The key is to get it to just freeze a little bit, which requires putting the beers in the freezer during a particular segment of the workout.

 

[btrueblood]

Phenomenon is called supercooling.

http://en.wikipedia.org/wiki/Supercooling

Interesting they talk about forming glassy water (ice) - i.e. cool it fast enough, and crystallization never occurs, and instead you have disordered, but solid, water.

 

[IRstuff]

a couple of good articles on the subject of supercooling:

http://polymer.bu.edu/hes/articles/ds03.pdf

http://polymer.bu.edu/hes/articles/gass04.pdf

This article, which requires payment, mentions another common supercooling phenomenon, which is more robust than supercooled water: supercooled sodium acetate, used for "instant" heating during the winter:

http://onlinelibrary.wiley.com/doi/10.1002/aic.690490222/abstract

What's interesting is that for sodium acetate, the freezing initiation requires a fairly energetic disturbance, i.e., the metallic clicker. Moreover, the heat of fusion isn't really removed until the trigger event, which is where the heating from the packet comes from.

What that says, then, is that supercooled water is technically not yet frozen, because the heat of fusion is still retained within the bulk of the material, and it's likely that the "instant" freezing is actually accompanied by a rapid rise in temperature. Might be interesting if someone actually does the temperature measurement during these events.

TTFN
faq731-376

 

[davidbeach]

That was freshman (high school) physical science. Yes there is a rapid temperature rise. Supercooled down to about -4C, when disturbed it froze solid and jumped to 0C.

 

[BigInch]

Also happens on aircraft wings, but changes instantly from supercooled water vapor directly to ice. No liquid phase involved at all.

From "BigInch's Extremely simple theory of everything."

 

[btrueblood]

Rime.

 

[GregLocock]

Nope, and it doesn't scan either. Must be that modern poetry.

Cheers

Greg Locock


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[BigInch]

Greg, Did it hurt when you fell to Earth?

From "BigInch's Extremely simple theory of everything."

 

[btrueblood]

Nicely struck, Greg. 'Course I lobbed it in right over the plate.

 

[Ron]

Triple point?