Re: FREEZING

The Question:
FREEZING

If water expands when is freezes, what happens if water is placed in very 
solid container is frozen. Does the water freeze without expanding?

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Dear Friend,

Before answering your question, I would like to rephrase it. You said: "Water 
expands by freezing. " , and this is a scientific fallacy. When you put the 
water in the freezer it changes into ice, and this is not considered expansion. 
It is some sort of physical change from one physical state to another one. For 
example, water as a chemical compound (H2O) has three physical states forms; 
either solid in the shape of ice, liquid as running water, or a gas in the form 
of water vapor. The difference between these three states is that the molecules 
of the compound differ in their inter molecular distance. In case of gases, 
particles are separated by large distance, and on the other side in solids they 
are solidly packed.
Then we should agree first of all on the new question:
 When we put water in the freezer it changes to ice…..till the end of your 
question.

What happens when water changes from running liquid water into ice? Say you 
had 1 Kilogram of water occupying 1 liter of volume (and this is by the way a 
fact; if you got your 1 liter fizzy drink PVC bottle and fill it with water, you 
will have approximately 1 Kilogram in your hand). When this Kilogram is 
undergoing transformation from liquid to solid, what happens is that the 
particles get closer and closer. Hence, the density of the water in its new form 
changes. Density gets lower in the new form. You may ask what is density and why 
low? Density is the mass of 1 liter of the a compound. May be you have heard 
about Archimedes’ principle that talks about floatation of bodies. From its 
famous results, that if you have two liquids and one of them has less density 
than the other, the less denser will be on the surface. That’s why you find oil 
floating on water surface and not the opposite because oil is less denser than 
water. 
Again why is ice less denser than water? I can relate it to you with 
something you may have seen. Perhaps you watched Titanic movie. Did you see the 
iceberg that hit Titanic? It was floating in the water surface. Hence, you 
deduce that ice is less denser than water.
 The equation for density says:
Density = (mass in kilograms / volume in cubic meters) (units are in Kg/m^3)

Assume we had 1 kilogram of water in our fizzy drink bottle, however we want 
this time a glass one so that you can her the noisy sound!! When you put that 
kilogram and then you put it in the freezer, the density changes. Hence the 
volume changes, however the mass stays constant.

So if

Ice Density X Ice Volume = Water Density X Water Volume = Constant mass
Hence if Ice density is less than the water density, therefore the ice volume 
must be larger than the water volume. If your bottle was completely full with 
water, you will hear a noisy voice of breaking glass, and you will know later 
what really happened!!

Now you ask a good question, what if water was compressed inside a solid 
container. Hence what do you think what will really happen?

Look my friend, expansion is not a weak force; it is a strong one that even 
as you may have seen break glass. This is one; second there is an important 
factor you should consider. In cold temperatures, materials get brittle to a 
very low extent. To simplify what is brittle for you, it is the same thing you 
will say about a piece of chalk that you can break. You know when Titanic was 
passing by the iceberg, the iceberg was cutting it in the same way a sharp knife 
cuts a piece of butter. 
  In WW II, the German tanks failed to advance in Russia because the Germans 
designed it to work in good weathers to very hot weathers. They built it from 
sort of material called cast iron; this cast iron become a piece of chalk in 
cold weather. Hence, these powerful armored tanks that destroyed Europe failed 
to advance in Russia. Their shields and armors failed, and they became easily 
penetrated by bullets.

  I have seen it myself in the American University Materials Testing Lab. We 
put a sample of Cast iron in liquid nitrogen, and it became really a piece of 
biscuit and not chalk.
So finally, what will happen in your case?
I can say that in low freezing temperatures, water will get very cold, but not 
freeze because there is no room for it to expand and there is pressure on it 
from all sides. However, if you decreased the temperatures more and more, you 
material will start to weaken weaken, until you may finally find it cracked or 
something similar. This weakening may not happen all of a sudden and it may take 
months or weeks of continuous freezing. 

This is my analysis. I hope it is convincing and useful. You have touched me 
by the way in my field of research which is materials science and technology. 
Thanks for the great question, waiting for feedback.

Moataz Attallah
The American University in Cairo
Email: Mizoa@aucegypt.edu

No sources were used.