Under Pressure

[iluvcrappie]

I have always wondered if as the ice gets thicker does it put more pressure on the water making the lake level rise    if you fill a glass half full and put a bunch of ice cubes in it the water level rises....right.......s o would it be the same for a lake?  do you think that it has an affect on how the fish bite or their activity?

[jayswimmer09]

well looks like you already got one good response, but really not as much pressure builds up as you think, if you look there are always stress cracks all over a body of water, these cracks are a way of the ice to relieve this pressure underneath, therefor not much pressure builds up

[Lone Fisher]

and its different because if you ADD ice cubes its already different because when the water freezes its from the first base material. not added water..

[Melbs7]

If you took a glass of water, and then withdrew 1/3 of the glass of water and froze the water you took out...leaving the glass of water only 2/3 full....and later added the ice from the 1/3 you removed, the glass would be the same level.  When a lake freezes, the layer of ice doesnt fall from the sky and land on the lake dude, the ice is water that was already there...not something "extra".  So the water does not "go up".  You smokin a thanksgiving doobie?...lol

You are right.... to a certain extent. However, ice is less dense than water. What does that mean? It means that 10 lbs of ice take up more space than 10 lbs of water. As water turns to ice, the ice takes up 1.087 times as much space as water. Especially towards the end of the season when the ice is getting thicker, you do notice that when you drill a hole, water flows up onto the  top of the ice. So, everytime that someone drills a hole in the ice, you are equalizing that pressure under the ice to what it would normally be.

Just my thoughts.

Dave

[InSearchOfPerch]

the ice takes up 1.087 times as much space as water. Just my thoughts.

Dave

lol...I knew someone would get technical and point this out.  But the point I was trying to make, somewhat sarcastically, was that the principle he tried to tie to the example he gave was not true.  The water for the most part does not rise, like it would if you took a lake at normal level and added a foot of ice to it by not using any water from the lake to make the ice.  I wasnt trying to be mean, just found the logic somewhat humorous.

[Melbs7]

Yeah, but I felt someone had to get technical!!  Anyhow.... I know that noone was trying to get mean... this web site is better than that!!!

Dave

[rgfixit]

Molecular basis for the Volume Increase of Ice:

The normal pattern for most compounds is that as the temperature of the liquid increases, the density decreases as the molecules spread out from each other. As the temperature decreases, the density increases as the molecules become more closely packed. This pattern does not hold true for ice as the exact opposite occurs.

In liquid water each molecule is hydrogen bonded to approximately 3.4 other water molecules. In ice each each molecule is hydrogen bonded to 4 other molecules.

Compare the structures of Liquid Water and Solid. The empty spaces within the ice structure, translates to a more open or expanded structure. The ice structure takes up more volume than the liquid water molecules.

WOW!

What the heck does this mean?

The increase in volume of frozen water is about 9%. Therefore 6" of ice represents an increase in volume of a tad more than 1/2 " over it's previous liquid state.

In answer to your question regarding increased pressure...a 1 gallon of liquid water weighs the same as that same gallon in it's frozen state.

Since a mass of frozen water has a greater volume than the equal mass of liquid water....it can be conjectured that the level of the lake may indeed rise if the lake's total volume remains constant. I'm not sure it is measurable.

My brain hurts.
RG

[FISHFORPIKE]

What happens when the "liquid", water, heats up?  Then your "normal pattern" holds true? i.e. as the water gets warmer - it expands?  I know, in this case it is irrelevant. 
I agree that the apparent level of the water would be indiscernible.  Ice floats on/in water something like 2/3 - 3/4 of it's mass below the water level?  This floating would seem to equal out (or maybe not even make up for) the displacement of the ice in the water.  In the later case this would lower the water from it's original level.
Also, if you drill a hole in the ice and the water comes up through the hole, there has to be some other physical force acting on the surface of the ice.  Usually, the only time I've seen this is when there is a lot of snow and slush on the ice.  Or when there is a group of people/vehicles in an area on the ice "pushing" it down.
Just my observations.

Molecular basis for the Volume Increase of Ice:

The normal pattern for most compounds is that as the temperature of the liquid increases, the density decreases as the molecules spread out from each other. As the temperature decreases, the density increases as the molecules become more closely packed. This pattern does not hold true for ice as the exact opposite occurs.

In liquid water each molecule is hydrogen bonded to approximately 3.4 other water molecules. In ice each each molecule is hydrogen bonded to 4 other molecules.

Compare the structures of Liquid Water and Solid. The empty spaces within the ice structure, translates to a more open or expanded structure. The ice structure takes up more volume than the liquid water molecules.

WOW!

What the heck does this mean?

The increase in volume of frozen water is about 9%. Therefore 6" of ice represents an increase in volume of a tad more than 1/2 " over it's previous liquid state.

In answer to your question regarding increased pressure...a 1 gallon of liquid water weighs the same as that same gallon in it's frozen state.

Since a mass of frozen water has a greater volume than the equal mass of liquid water....it can be conjectured that the level of the lake may indeed rise if the lake's total volume remains constant. I'm not sure it is measurable.

My brain hurts.
RG

[rgfixit]

So......what does that mean?

Inquiring minds want to know
RG

[FISHFORPIKE]

   Don't know - Melbs7 made a comment that when a hole was drilled in the ice, the water rose through the hole and onto the ice. My experience, for the most part, is that the ice is floating on the water, not that the water is under pressure from the ice.  I suppose that it IS under pressure (atmospheric, for one); just not enough to "push" the ice under the water.  If that were the case, the water level would definitely rise.

My brain hurts more than yours 

So......what does that mean?

Inquiring minds want to know
RG

[Turkeyhunter10ga]

Especially towards the end of the season when the ice is getting thinner, you do notice that when you drill a hole, water flows up onto the  top of the ice. So, everytime that someone drills a hole in the ice, you are equalizing that pressure under the ice to what it would normally be.

Just my thoughts.

Dave

Wow, and here all along i thought it was cuz the ice was getting thinner and i weighed a bit more with all the extra clothes i had on.

Yeah, but I felt someone had to get technical!!  Anyhow.... I know that noone was trying to get mean... this web site is better than that!!!

Dave

Keep up this technical stuff and i'll have to ask Jenn if you are the real Dave or some alien imposter .

[Melbs7]

 


Dave

[pikeking]

ICE FLOATS!!!