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Author Topic: How Cold Can Running water Get ?  (Read 8518 times)

Offline neilep

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How Cold Can Running water Get ?
« on: 14/03/2006 20:46:55 »
Greetings,

Is there a limit to the speed water can be propelled at that will keep it from freezing ?

....a fast moving river ?....or a high pressure hose ?

Is there on record anywhere about really cold water that hasn't frozen because it is moving ?

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Offline Hadrian

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Re: How Cold Can Running water Get ?
« Reply #1 on: 14/03/2006 21:03:41 »
This is Don Juan Pond in Antarctica, It's a high salinity pond with liquid water at temperatures as low as -24 C."


 a very shallow pond (here shown during a dry spell) that is the only liquid body of water in Antarctica. This pond has so much CaCl2 dissolved in it, it never completely freezes, even in the dead of the Antarctic winter when temperatures may reach -50C (-58F)!


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Offline neilep

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Re: How Cold Can Running water Get ?
« Reply #2 on: 14/03/2006 21:16:45 »
This is great !!..You pose a question...you get an answer !!....someone really ought to construct a website that serves this purpose of answering science based questions !!...............DOH !!

Thanks Hadrian.


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Offline DoctorBeaver

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Re: How Cold Can Running water Get ?
« Reply #3 on: 14/03/2006 21:31:39 »
Hadrian - But that doesn't answer the question. Neil asked about flowing water and your reply is about salinity (or in my case, senility).

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Offline neilep

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Re: How Cold Can Running water Get ?
« Reply #4 on: 14/03/2006 21:56:26 »
...yep, I must admit I did notice that, but I wanted Hadrian to enjoy his ' moment '...cos I'm a super nice guy who is also senile !!...

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« Last Edit: 14/03/2006 21:57:01 by neilep »
 

Offline DoctorBeaver

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Re: How Cold Can Running water Get ?
« Reply #5 on: 14/03/2006 21:59:57 »
I'll forgive him, though, as he's a Beaverland member :)

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Offline ariel

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Re: How Cold Can Running water Get ?
« Reply #6 on: 15/03/2006 01:06:42 »
ariel has registered to be a beaver   :D
 

Offline tweener

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Re: How Cold Can Running water Get ?
« Reply #7 on: 15/03/2006 03:34:32 »
I'm not an expert here, but I believe that even moving water will freeze at 0 C.  Crystals will form and stick to anything they can basically causing a slush to form.  Certain conditions can result in "supercooling" - I'm not sure just how that works, but I believe it is when the water is very still and very pure and the crystals just don't have a place to start.

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Offline Hadrian

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Re: How Cold Can Running water Get ?
« Reply #8 on: 15/03/2006 09:37:14 »
I thought movement was relative. This pond doesn't have a river attached to it as such. But there has to be flow of sorts as water is blown off it during storms is replaced is that not movement? Ice at the edges is dissolved by the salts and also has to cause flow all be it small movement. If at any time it is perfectly still then this would prove that water with this mineral content wont freeze at zero flow rate. But then again is this relative to time. We have to hold on  till hell freeze over to please some people.  Anyway I get my snow shoes on and take a look see if I can't get some flow rates for you. LOL

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Offline Hadrian

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Re: How Cold Can Running water Get ?
« Reply #9 on: 15/03/2006 11:45:45 »

Lake Vostok

Lake Vostok is the largest of more than 70 subglacial lakes in Antarctica. The average water temperature is around 3 C, below normal freezing point because of ice pressure. Heat from the Earth's interior (geothermal) warms the bottom of the lake. The ice sheet itself insulates the lake from cold temperatures on the surface.

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

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« Last Edit: 15/03/2006 11:46:53 by Hadrian »
 

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Re: How Cold Can Running water Get ?
« Reply #10 on: 15/03/2006 17:05:34 »
quote:
Originally posted by Hadrian

I thought movement was relative.



Quite so, but in a fast moving stream (as distinct from a deep river) the edge of the river is constantly impacting the shores, and being channelled narrow gaps that with alter the local pressure within the water.




George
« Last Edit: 15/03/2006 17:05:55 by another_someone »
 

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Re: How Cold Can Running water Get ?
« Reply #10 on: 15/03/2006 17:05:34 »

 

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