48 votes
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How strong is the force of ice expanding when freezing?

But what would we get? Compressed ice? Can this even be done? Can you compress ice? Absolutely; all passive materials can be compressed. The bulk modulus, a material property with units of pressure, ...
Chemomechanics's user avatar
44 votes
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How does defrosting your freezer save energy?

Refrigerators and freezers work by running a really cold liquid through cooling pipes fitted in the cavity to be cooled. This flow (the compressor) is switched off when the set temperature is reached, ...
Gert's user avatar
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29 votes

Why is ice made from boiled water clear?

I'm really winging this one because the last time I did an equilibrium calculation was 35 years ago! But I'm fairly sure of a partial answer (see discussion at end). A gas's solubility in water (or ...
Selene Routley's user avatar
29 votes
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Why is ice made from boiled water clear?

The short answer: Cloudy ice is caused by gases (mainly nitrogen and oxygen) dissolved in the water that come out of solution when the water freezes. The small bubbles trapped in the ice cause the ...
Previous's user avatar
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22 votes
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Can water at absolute zero still be liquid?

The phenomenon is called supercooling: A liquid crossing its standard freezing point will crystalize in the presence of a seed crystal or nucleus around which a crystal structure can form creating a ...
Roger V.'s user avatar
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15 votes
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Freezing water: in layers or all at once?

Water in a fluid phase has density of $1.00~\text{g/cm}^3$, while in a solid form (ice) - $0.92~\text{g/cm}^3$. So while freezing water expands in volume (and thus drops in density), it becomes ...
Agnius Vasiliauskas's user avatar
12 votes

Why is ice made from boiled water clear?

This answer was meant as a comment to @WetSavannahanimal aka Rad Vance but it is rather long and I hit the character limit. The reason for the opaque center should be due to the manner in which the ...
Carel's user avatar
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12 votes

How strong is the force of ice expanding when freezing?

Summary: Per Chemomechanics’ Answer, to -22C: It will cool as water at room pressure and temperature and volume (and hence room density) to 0C. Then as it is cooled it goes from 0C water to 0C ice-...
Al Brown's user avatar
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11 votes
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Why can a contrail only form below -40 degree Celsius?

The -36.5 Celsius figure came from a theory describing contrail formation developed by Appleman in 1953. This theory gives rise to the Appleman chart, as shown below, which predicts whether contrails ...
probably_someone's user avatar
9 votes
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How does frost form above freezing temperature?

The (long-term) temperature of an object depends on the heat transfer between it and all of the environment. Air isn't a great conductor of heat. So if there is little air movement, the radiation ...
BowlOfRed's user avatar
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9 votes

What causes this frost pattern on my windshield?

Patterns like this are most often caused by scratches in the glass surface that are too small to see with the naked eye, but which act as nucleation centers for the deposition of frost from ...
niels nielsen's user avatar
8 votes

Vacuum freezing of water

water takes energy to boil from itself, leaving behind the solid ice Yes, that's essentially what happens. If it feels strange, remember that the process of evacuation is removing energy from the ...
stafusa's user avatar
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8 votes

Making energy out of freezing ice

Since water expands so greatly when frozen could it be possible to freeze the water in a metal cylinder but one side is like a car piston with a very high gear ratio which would be no problem to turn ...
Chemomechanics's user avatar
7 votes
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At the freezing point, why is the vapor pressure of the liquid phase equal to the vapor pressure of the solid phase?

When two phases are in equilibrium the chemical potential of the atoms/molecules in the two phases are the same. If you're not familiar with the concept of chemical potential it basically just means ...
John Rennie's user avatar
7 votes
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Why doesn't the moisture freeze out of the air when the air temperature is below freezing?

Even at the height of summer, it's well below the boiling point of water, and yet there's still water vapor in the air. The reason that water vapor can exist in the atmosphere below the boiling point ...
David Hammen's user avatar
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7 votes

Freezing water: in layers or all at once?

The surface of the water evaporated due to partial pressure. As this transformation from a liquid to a gas state costs energy (the so called latent energy), the remaining water becomes "cold"...
Semoi's user avatar
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7 votes

Freezing water: in layers or all at once?

For a centimeter or so, I wouldn't try to complicate it. Given cold enough temperatures, that depth can freeze solid in a single night. Also, trying to control the layers thinner than that would be ...
BowlOfRed's user avatar
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7 votes

How strong is the force of ice expanding when freezing?

About energy conversion in the process: If the principle of conservation of energy holds good then energy is converted only, in that sense the work done by expanding cannot exceed the energy ...
Cleonis's user avatar
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7 votes

Why do some oranges freeze while others don't at the same temperature?

This is a nontrivial question... So we start by testing the most straightforward hypothesis: An orange that was deficient in sugar would freeze at a slightly higher temperature than a sugar-rich ...
niels nielsen's user avatar
6 votes

How does defrosting your freezer save energy?

The following point wasn't made in the other answers. The efficiency of a refrigeration cycle is determined by its coefficient of performance (COP), defined as: $$ COP = \frac{|Q_L|}{|W|} $$ $Q_L$ ...
tvo's user avatar
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6 votes
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How fast can water from a lake be frozen?

As we don't know anything about the intial temparature of the water, another fun but unlikely explanation would be to consider what we call supercooled water. Basically, at atmospheric pressure, ...
Barbaud Julien's user avatar
5 votes

How strong is the force of ice expanding when freezing?

The other answers are excellent in explaining the theory. There is a good Youtube video "Can You Stop Water From Expanding When It Freezes Into Ice" showing a practical experiment trying to ...
Erl's user avatar
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5 votes
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Why doesn't 250 ml of tap water kept outdoor in -2 °C freeze to ice?

The reported air temperature is only one aspect of the thermal environment that an object finds itself in. The radiative environment is also important: Is it sunny during the day? Is there a (heated)...
BowlOfRed's user avatar
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4 votes
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Is it a myth that having bottles with ice in the freezer improves performance?

I would like to qualify the answers offered by @Bort and @sammy gerbil based on crude estimates given below. Consider a fridge with perfect thermal insulation. Initially it is filled with air at room ...
Deep's user avatar
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4 votes

At the freezing point, why is the vapor pressure of the liquid phase equal to the vapor pressure of the solid phase?

What you have to remember to understand this is that everything has an interface, either be solid or liquid. It's at the interface (typically, but not necessarily, at the outermost interface) that it ...
cinico's user avatar
  • 1,344
4 votes

Freezing water: in layers or all at once?

For fastest freezing make sure the rink is shaded during the day, and exposed to the sky at night. Optionally you can add environmental snow or ice to the fill water to reduce the amount of cooling (...
Jasen's user avatar
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4 votes

Making energy out of freezing ice

Historically, your question is very interesting. The idea that it would seem possible to use this phenomenon to produce work was discussed by William Thomson (the future Lord Kelvin) and his brother ...
Vincent Fraticelli's user avatar
3 votes

Will the water added to an ice piece freeze?

Water kept in the hole loses heat to the ice and cools down to 0°C. Here, both ice and water are at same temperature so that water cannot give out Latent heat to the ice and hence it does not ...
Misty's user avatar
  • 31

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