A beautiful sunny day in Vilnius

[Dry]

Originally posted by Serb
1) Once again, at 0C water becomes ice.

Thanx for the advanced physic lesson , but on none of the pics do I see people swimming in ice. Read again my post and you'll notice I talked about liquid water, at normal atmospherical earth pression.
...ok, I didn't mention earth...
The only thing I cannot tell from the pics is if they are in river, lake or sea water.

Originally posted by Serb
What you failed to understand is there is a big difference to undress and dive into an ice-hole when it's -0C and to do the same when it's -40C. When you get out of water you are wet.

I don't fail to understand, read again my posts:
... well, as long as you don't step out, of course...
and
... as long as you don't wet your head/hairs.

So, the colder the air outside, the thicker the ice on the river and the colder the water below the ice layer. Simple as that.
So, all claims that the temperature of water is always the same regardless of the outside temperature are plain wrong. This temperature can't drop below 0C, it's true, but it's still different for -40C and 0C.

Serb, you are correct, to some point.
As long as water is liquid, not polluted, salted, depressurized... or agitated, temperature cannot go below 0C.
No need of geothermal activity. The ice, the thickness of the ice on your rivers will provide an isolation layer for the liquid water below, and that's how not ALL the water will freeze.
Same for the ground (see permafrost thickness).
The colder the thicker the ice, because the cold needs to penetrate this isolation layer.
Now, dig a hole in this ice, and indeed, the cold will 'hit' the naked surface of liquid water and the water there, being UNABLE to go below 0C (or more likely -2C or -4C) will HAVE to freeze. The colder the faster.

Now what is well true is: take a river by -30C, thick ice layer; dig a hole in that ice; as everybody knows, the cold will sink in that hole; so basically you have make some kind of coldness trap, sinkhole.
I agree it must be dam' freezing down there, even more than just on the surface of the ice.
And as everybody knows, a great part of the body heat is lost via the head.
So basically, those guys are putting their head in a d** f**** freezer... those religious people...

[Serb]

Originally posted by Dry

Thanx for the advanced physic lesson , but on none of the pics do I see people swimming in ice. Read again my post and you'll notice I talked about liquid water, at normal atmospherical earth pression.
...ok, I didn't mention earth...

Water cannot be liquid at 0C (at normal pressure) as you claimed earlier At 0C it becomes an ice.

The only thing I cannot tell from the pics is if they are in river, lake or sea water.

You aren't Christian? The ritual is dedicated to baptism of Jesus in the Jordan river and it's comitted at rivers, not seas.

I don't fail to understand, read again my posts:
... well, as long as you don't step out, of course...
and
... as long as you don't wet your head/hairs.

Then why your: "I hate to hurt your blah-blah-blah this and blah-blah-blah that?"

Serb, you are correct, to some point.
As long as water is liquid, not polluted, salted, depressurized... or agitated, temperature cannot go below 0C.

It's a basic knowledge.

No need of geothermal activity. The ice, the thickness of the ice on your rivers will provide an isolation layer for the liquid water below, and that's how not ALL the water will freeze.
Same for the ground (see permafrost thickness).
The colder the thicker the ice, because the cold needs to penetrate this isolation layer.

Sure, but when you have a thin ice layer and -5C outside the temperature of water will be greater than when you have a thick ice layer, because it's -40C outside, simply because the ice will have a greater mass and temperature and thus will influence the water stronger. The temperature of water below the Antarctic icebergs can't be the same as temperature of water below a thin ice layer in a puddle at November (or December?) somewhere in Belgium. The temp can't go below zero, but still it's different.

Now, dig a hole in this ice, and indeed, the cold will 'hit' the naked surface of liquid water and the water there, being UNABLE to go below 0C (or more likely -2C or -4C) will HAVE to freeze. The colder the faster.

I was talking about the same. Except, the vapor will be much more visible under -40C than under 0C.

Now what is well true is: take a river by -30C, thick ice layer; dig a hole in that ice; as everybody knows, the cold will sink in that hole; so basically you have make some kind of coldness trap, sinkhole.
I agree it must be dam' freezing down there, even more than just on the surface of the ice.
And as everybody knows, a great part of the body heat is lost via the head.
So basically, those guys are putting their head in a d** f**** freezer... those religious people...

Watch your tongue, dude You are talking about hell knows how many millions of my countrymen who commited and still commit this ritual for centuries regardles of any circumstances, not about a tiny sect of some kind of fanatics.
My sister is a very poor swimmer and she rarely swims even at summer, but she commited the ritual when it was well below -40C. And of course she didn't cough after that (actually, nobody does).
I admire the spirit of the people who have balls to went through that, because I am a pretty good swimmer and consider myself as strong male, but when I think about being naked and wet after diving while it's below -30C/-40C or even -50C - NO WAY!!! I'm not so strong.

[Az]

Water cannot be liquid at 0C (at normal pressure) as you claimed earlier At 0C it becomes an ice

Actually, at 0C, a water-ice equilibrium exists. What this means is that if you see a bunch of water, in a bunch of ice, it's temperature is 0C.

EDIT: that's the number for pure H20, that is. The number is slightly lower, depending on salinity of the water, and stuff like that.

[Serb]

It depends on system we have. I think you mean a fully enclosed system where the amount of ice = the amount of water and there is no any other external influence?
I meant a normal conditions - the system which consist of water in the river and surrounding stuff like air and banks (at normal atmospheric pressure).
At normal conditions the freezing point of water is 0C and I've never said the temperature of the water in the ice-hole is 0C. I said that temp of the water in an ice-hole in Denmark below, let's say, 5cm layer of ice, when it's -5C outside, is higher than the temp of the water below the 50cm of ice layer in Siberia when it's -40C outside. In both cases it will be higher than 0C, but still different.

[Az]

You don't have to have the amount of ice equal the amount of water, and you don't have to have an enclosed system. the temperature of the water in which you have a serious amount of ice in the water will be basically 0 degrees. Of course you'll have a constant incoming source of heat from the heat reservoir of deeper water, but if you have water + large chunks of ice floating in it, or a small hole full of water through a thick layer of ice, I think the temperature of the water will effectively be zero celcius.

[Serb]

You were talking about a water-ice equilibrium, remeber? With "constant incoming source of heat from the heat reservoir of deeper water", such equilibrium simply can't exist.
If get you corectly you meant a thin (surface) layer of water, while I meant the whole mass of (deeper) water. And my message was pretty simple - the lower temperature you have on the surface, the thicker the ice and the lower the temperature of the water in the entire system.
I realize that my thermodinamics might suck, since last time I have such lection was ten years ago, but from I remeber a water-ice equilibrium can be achived only in perfect conditions in a fully enclosed system. Which is not the case in case of river, simply because it's a complicated system where large masses of water moves constantly.

[Az]

I've said that in 0 degrees, ice and water have equal thermodynamic standing, that's what I meant by them being in equlibrium in 0 degrees. I am sorry, maybe I should've worded it differently. and in the case of water enclosed in a body of ice, where there is plenty of surface area in relation to the local body of water for them to make contact you can treat it as if it in equilibrium, since the amount of heat coming from below is negligible in relation to the surface area with the ice, locally. Thus, if the water doesn't freeze, and the ice doesn't begin to melt, it's at 0 degrees.

[VetLegion]

Did you folks know that hot water freezes faster than cold water? Now you know.

[Serb]

Originally posted by Az
I've said that in 0 degrees, ice and water have equal thermodynamic standing, that's what I meant by them being in equlibrium in 0 degrees.
I am sorry, maybe I should've worded it differently. and in the case of water enclosed in a body of ice, where there is plenty of surface area in relation to the local body of water for them to make contact you can treat it as if it in equilibrium, since the amount of heat coming from below is negligible in relation to the surface area with the ice, locally.

These were a keywords. You are talking about perfect conditions: "water is enclosed in a body of ice, where there is plenty of surface area in relation to the local body of water for them to make contact". This is not the case in case of river. Of course it depends on circumstances such as depth and outside temperature, but normaly, the volume of ice layer is small in comparison with the volume of whole body of water. And we could see something similar with equilibrium only in thin layer of water which makes contact with ice layer. And this layer is pretty negligible in comparison with the rest body of water. The deeper we go, the hotter the water is. For a man who dives in an ice hole it's hard to notice this layer of equilibrium. He feels the temperature of the entire water, not a thin layer of it. And the colder the air is, the more ice you have and the colder the water will be. I mean at 0C, at 1 meter depth, the water will be warmer than at the same depth while the temp of air is -40C.

Thus, if the water doesn't freeze, and the ice doesn't begin to melt, it's at 0 degrees.

Of course.
We probably could get this in a perfect conditions: we can take a thermos bottle and fill half of it with water with temp very close to zero and then start to add some ice there to cool off the water to gain the equilibrium.
But you can't achieve this in real conditions in our system (a river with an ice-hole), because the river flows and except surrounding ice there is a cold air which also influences the water in the ice-hole.
So, basically what I mean is:
a) in our system at -30C, the surface of the ice-hole will freeze faster than at 0C.
b) the temp of the water will drop faster in case of -30C outside, thus the water will be colder.
If you have a glass of water with temp let's say +20C, where the water will chill off faster in a room with 0C or in a room with -30C?


WTF are we argueing about?

[Az]

I am not saying that the temperature of the water is 0, since it's not even even across....ahh **** it, it's 2 AM.

[Vince278]

It just went down to 1C here. Time to throw another log on the fire.