legends of the south pole

nicholas bonham-carter

This article seems to allow the possibility of a different freezing point for water, which is hard to believe. Surely it must be a misinterpretation of some other phenomenon.--NBC



<a href="http://www.wired.com/2014/08/wuwt-weather/">http://www.wired.com/2014/08/wuwt-weather/</a>

icesailor

It's true:

It's true. Water under certain conditions, doesn't freeze until as low as -40. And it can freeze as high as 39+ degrees.  But it ALWAYS melts at 32 degrees.

Although frozen water/ice melts at 32 degrees, water, in the form of pure water can freeze at 32+F to as low as -40. It has to do with "Pure Water" as like distilled water. There are no solids in the water.

There is moisture in the form of evaporated water that becomes pure when it evaporates. At 30,000', there is moisture but it is invisible. Not until the moisture can gather on a speck of dust, can the water vapor convert and freeze, forming clouds. Its called "Super-Cooled Water Vapor".

A good common example of the phenomenon is if or when you put a bottle of beer of bottled water in the freezer to chill it and you forget it. And you remember it before it becomes solid. You pull out the bottle and see that it is still liquid. But, if the conditions are right, because you have disturbed the tranquility of the water in the bottle, you might see a cloud form (in the form of slush) at the top of the bottle and slowly descend to the bottom. The contents of the bottle have turned to slush. We who lived in The North, might see it commonly if we leave bottled water bottles in a truck outside at night on below 32 degree weather. It is common on nights when it is clear and you get radiational cooling.The water doesn't freeze until the bottle is agitated.

When you see aircraft passing overhead and they leave contrails behind, it is the soot from burning hydrocarbon fuels that is reacting with the water vapor present and the exhaust gasses that form the Contrails or clouds. That's the theory behind "Cloud Seeding" to make rain. If you put enough dust or debris into the atmosphere, and enough moisture gathers on the dust, it becomes too heavy and finally falls in the form of rain.

If I put bottled water or flavored water in the very back of my refrigerator for long periods of time, I might get one out and I can watch the phase change. If I catch it right. I can make it happen in the freezer. Beer does it when it is shaken or moved because it is reacting to the CO2 in the beer. Beer does it just as well as water. Watch for it.

Super Cooled water vapor does this on aircraft surfaces where water can freeze as high as 39+ degrees because of the cooling effect of air moving over a surface in a vacuum, which lowers the temperature of the water vapor and it sticks to the surfaces it can find. Like wings and propellers.



http://www.sciencedaily.com/releases/2011/11/111123133123.htm

Jamie Hall

And to add to Ice's comments...

Supercooled water in clouds is a pilot's worst nightmare.  The stuff is liquid -- rain, for all practical purposes -- until your wing and tail hit it.  Then it turns into ice, heavy ice, practically instantly and you  de-icing gear can't get rid of it.  If you're really lucky and have been living right, you fly out of it into warmer air and can recover.  If not you have an unplanned encounter with mother Earth, which can ruin your whole day.

icesailor

CFIG

Also known as CFIG. Controlled Flight Into Ground.

And you don't have to be flying in clouds. As long as the temperature, humidity and dew point align in the proper manner, you can be toast. Even with the prop de-icers working, the sound of ice flying off the props and hitting the side of the airplane, can make you feel like you haven't been a good enough person yet.