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Author Topic: How does freezing water break a pipe?  (Read 5993 times)

Offline JukriS

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How does freezing water break a pipe?
« on: 31/10/2008 11:12:46 »
"How can freezing water expand, even bursting metal pipes, with no energy input to explain it?

A: According to today's science, this is impossible. Every output of energy requires a balancing energy input in order
to remain within our laws of physics. A balloon left in the sun will expand and burst, in the process doing work against the
surrounding atmosphere and its elastic skin, which is balanced by the energy input from the sun, so it is no mystery. However,
freezing water has no energy input -- in fact, just the opposite. Energy continually drains from the water as it cools toward
freezing. So, how does the water suddenly expand with such force from within that it easily bursts metal pipes? No solid
answers to this mystery can be found from today's scientists -- only confused hand-waving diversionary responses that still
do not answer this clear energy balance violation."

http://www.thefinaltheory.com/scienceflaws.html

Is today's physics hand waving physics?

Thats the way it is!

« Last Edit: 01/11/2008 10:25:31 by chris »


 

Offline graham.d

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Re: How does freezing water break a pipe?
« Reply #1 on: 31/10/2008 13:32:36 »
I believe the reason that water expands close to feezing is to do with changing from a compact state, with little wasted space between the aligned hydrogen bonded water molecules at about 4C, to a crystalline state which requires the bonds to be deformed slightly, and occupying more space as a result, at 0C. I don't think there is any violation of conservation of energy laws here. In fact holding the freezing water in a confined space whilst continuing to cool will delay the phase change to a lower temperature in the same way that applying pressure to ice close to 0C will cause it to melt. I think it is just that we are used to a correlation between expansion and increase in temperature. If you take a long piece of metal and cool it so it contracts, it would not surprise anyone to think that you could extract some energy from the movement of the end of the metal if the other end were fixed - to lift a small weight via a system of levers for example.
 

lyner

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Re: How does freezing water break a pipe?
« Reply #2 on: 31/10/2008 19:14:35 »
Considering the energy involved, there is a lot of energy transferred whilst water is cooling and freezing. Some of it, and there is not a lot of actual energy involved, goes towards some mechanical work.
Why do I say there is not much mechanical work? Work is defined as force times distance. The force may be high but the distance is very little.
The actual thermal energy transferred is enormous in comparison.
If you really insist I will do the sums but I am tired.
 

Offline DoctorBeaver

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Re: How does freezing water break a pipe?
« Reply #3 on: 01/11/2008 05:09:22 »
I believe I'm right in saying that all other things being equal, temperature increases with pressure. If the water was cooled to freezing point in a rigid container that was strong enough not to split, it would try to expand but not be able to. That would increase the pressure and, hence, the temperature also. Could the water be stopped from freezing like that?
 

Offline graham.d

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Re: How does freezing water break a pipe?
« Reply #4 on: 01/11/2008 09:57:06 »
Dr B, your initial premise is that the water and container was being cooled so, by definition, the temperature will not increase. The pressure lowers the freezing point but will not prevent freezing if cold enough.
 

lyner

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How freezing water can break pipe!
« Reply #5 on: 01/11/2008 10:36:34 »
Your rule of thumb relating temperature and pressure applies to gases, under adiabatic conditions (in an insulated container) because the work done to increase the pressure increases the internal energy. In an isothermal change , you increase the pressure slowly and the excess internal energy leaks away to the surroundings. What I am saying is that high pressure doesn't actually imply a higher temperature. Increasing pressure does, however, involve an input of energy. (Subtle difference)

Where you have a change of state (or even interaction between molecules) the simple model no longer applies. When water is frozen (near 0C), you can melt it by increasing the pressure (e.g. under ice skate blades). The energy you have added supplies the latent heat of melting.

The pressure due to freezing is not 'unstoppable' and you can delay freezing if you keep the water in a strong enough container. The temperature could not 'go up' because the surroundings would be taking energy away. What you could say, however, is that there would be less energy lost to the container if it were under pressure than if it were not - because the latent heat of freezing would not be available.

If you want to use the word "try", you are implying an intention and substances certainly don't have intentions. This may sound very nitpicking (not for the first time!) but that sort of word can lead one into problems. Using inverted commas ('try') shows that you mean "behaves as if it were trying to", which is a better way of putting it.
 

Offline DoctorBeaver

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How does freezing water break a pipe?
« Reply #6 on: 02/11/2008 20:22:29 »
graham & SC - thank you.
 

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How does freezing water break a pipe?
« Reply #6 on: 02/11/2008 20:22:29 »

 

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