minimum freezeing point of water?
606548
Absolute zero.  There are ways to keep water from freezing using pressure, motion, impurities, and so forth.
273724
No.  The point is always 32 degrees farenheit, assuming pressure at sea level.\n\nThe amount will not affect the freezing point, but other factors, such as pressure, will.
1096429
Ice requires a crystalline lattice structure. The salt ions (Na+ and Cl-) physically interfere with the formation of that lattice structure by standing in the way of water molecules. A lower temperature is therefore necessary to form ice and so water that contains ionic salt can drop to lower temperatures before forming ice. The same general effect applies to boiling water. Because the salt prevents molecules from escaping into the atmosphere as gas, the boiling point is raised.\n\nNote: I assume you meant 0 degrees Celsius. The Fahrenheit scale is somewhat different, since water freezes at 32 degrees Fahrenheit. But don't let these numbers cause you to believe something different is going on in the salt/water/ice mixture. The Celsius scale is set such that water freezes at 0 degrees (absent salt). This doesn't mean that at 0 Celsius and below there is no temperature or energy. Just the same, below 0 degrees Fahrenheit compounds still have energy and temperature. Scientists tend to use another scale which more accurately depicts true temperature, which is the Kelvin scale. In the Kelvin scale, absolute zero- the temperature at which all molecules and atoms stop moving- is really 0. But 0 Kelvin is much lower than either 0 Celsius or 0 Fahrenheit. To convert from Celsius to Kelvin, just add 273 degrees (or subtract 273 from Kelvin to Celsius). So 0 Celsius is actually 273 degrees Kelvin.  \n\nIn any case, if you were looking for an answer that has to do with the chemical properties of the salt/ice/water mixture, and why, for example, salt tends to lower the freezing point (or raises the boiling point), my first answer is right.  Any solute you add to a solvent will change the colligative properties of the solvent.  It interferes with the organization of water molecules such that they have a harder time aligning into a crystalline ice pattern, and therefore a lower temperature is required for ice to form. Note also that whenever you have an ice/water mixture, the entire mixture maintains the same temperature until all of the water has turned to ice. That is, in pure water that contains ice, the water will stay at 0 degrees Celsius until all the water has turned to ice, and then the ice will gradually drop in temperature. The salt just lowers that freezing point, but the same applies, just that the salt/water/ice mixture remains at that lower freezing point until all water as frozen, then it drops further in temperature.
899981
This is what happens if you start freezing a glass of sea water: it will start to freeze at a lower temperature than fresh water (around -4 C, but variable depending on the salinity you start with). \nImportant, the salinity of the ice formed is almost pure water (it is not salty). Some salty water may be trapped on the ice though, but the ice itself is fresh water. If you keep lowering the temperature, more ice will form and the remaining salty water gets even saltier. This process will continues until an eutectic is reached and then you will have a fast crystallization of ice, a mineral called hydrohalite. This eutectic is about -21 C, but depends on other components, like Mg, Ca that are also abundant in the composition of sea water.
86483
Actually, Gonpatrick, the original question is quite correct: Unlike most substances, water does actually expand when it is cooled, over a narrow temperature range from about 4 degrees C to 0 degrees C (the freezing point.)  This is why water freezes from the top down: the cooler water that is closer to freezing is less dense than, and so floats above, slightly warmer water.  (Above 4 degrees C, water expands when it is heated just like most other substances.) When the water freezes it expands some more, which is why ice floats.\n\nThe reason why it does this has to do with the way water molecules are put together.  The two hydrogens and one oxygen in H2O are assembled in a triangular pattern, with one part of the molecule more positive and the other more negative.  Above 4 degrees C, the molecules move freely around each other, but when it gets close to its freezing temp, the molecules start to align themselves with the positive part of one molecule near the negative part of another, ultimately forming, when it freezes, a hexagonal pattern.  This arrangement takes up more room than when the molecules are free to move around.
1019201
First you have to know the pressure and the exact salinity to answer this question.\nBut generally :\nAt a salinity of 35PPT and a pressure of 1.5 PSI\nthe freezing point would be -1.930 degrees C or 28.5 F
162986
We typed "how does salt melt ice" into the Yahoo! Search box and were soon traveling the well-worn path to How Stuff Works. \nThere we learned that the answer has to do with melting points. Most people know that water freezes at a temperature of 32°Fahrenheit (0°Celsius). Salt dissolves fairly rapidly in ice, lowering its freezing point in an effect known as freezing point depression, and melting it in the process. \n\nBut what's going on at the molecular level? Basically, salt molecules are bonding with water molecules, making it more difficult for ice to form. The result is a solution with a lower freezing temperature. For example, a 10% salt solution freezes at 20°F (-6°C), while a 20% salt solution freezes at 2°F (-16°C). \n\nYou've also probably noticed the effect of salt water on freezing points if you've tried to make ice cream or if you've wondered why the ocean doesn't freeze at the same time as bodies of fresh water, such as rivers, lakes, and ponds.
541181
See this answer.  Dig into the citations for the reference articles in them.  The second also has references.\n\nHot freezes faster in many cases, given certain controls such as same amount of water, same size and shape container, standard pressure etc.  There  is at least one experiment showing that water at 90 degrees C will freeze quicker than water at 18 degrees C.  This is significant since one side is quite close to boiling and the other is basically room temperature.\n\nIf you are not a high school student, I would look up linear programming ( a branch of algebra not computer science) and develop a sensitivity analysis to determine the impact of various effects.
1010626
Could be that different chemical compounds freeze at different temperatures.  Water freezes at a lower temperature than 36 degrees but not everything does.  That is also like why you put salt on ice to thaw it, it lowers the freezing point, so it has to be a lot colder before you get ice.
211914
It depends on the mass. The latent heat of fusion of water (the energy required to freeze it) is 333.7 kJ/kg. That means to freeze one kilogram of water, it requires removing 333.7 kilojoules of energy.\n\nThis assumes that the water is already at freezing temperature. If not, energy must first be removed to get it at freezing temp.
182633
A: Saltwater has a much lower freezing point (the freezing point is the temperature where something freezes) than freshwater does. And the more salt there is in it, the lower the freezing point gets. So in order to know the exact temperature that it's going to freeze, you have to know just how salty it is. For saltwater that's as saturated as it can possibly get (i.e. there's no way to dissolve any more salt in it no matter how hard you tried), the freezing point is  -21.1 degrees Celsius or -69.98 degrees Fahrenheight. This is when the saltwater is 23.3% salt (by weight).
53261
salt's chemical composition breaks down bonds at an intermolecular level and lowers the freezing point of water...which is normally 32 degrees Fahrenheit. When the freezing point goes down...it melts
726926
Salt... When applied to ice, the salt (NaCl) dissolves into the water creating a salt water mixture which has a lower freezing point than pure water.\n\n10% salt solution freezes at 20 F (-6 C)\n20% salt solution freezes at 2 F (-16 C)\n\nSalt becomes less effective at temperatures below 0F (-32 C).\n\nEnjoy!
60893
Sodium Chloride (NaCl), or salt, lowers the freezing point of water.  Putting salt on ice turns it back into water UNTIL the temps drop below the point where the salt water will freeze again which is between -9°C (15°F) and -21°C (-6°F) depending on the amount of salt suspened in the water.
528335
A liquid is not frozen, it is liquid. Liquid nitrogen is liquid, you can pour it. Freezing Point @ 1 atm: -346.0°F (-210.0°C, 63oK) puts it in a solid state.
587656
So anti-freeze and salt causes a freezing point depression in the water which means as you add solvent such as salt the freezing point is lowered (hence when you add salt to your windshield the ice melts).  There is a simple mathematic equation that will relate the change of Temp freezing to the amout of solvent added.  (ΔTf = Kfcm).  Kf is the freezing point constant of the solvent and cm is the molal concentration of the solvent. So as you can see from the equation the ΔTf will be greater as you increase cm so the effects of adding a solvent will depend on how much solvent you add.  \n\nSo a simple experiment would be to add increasing amounts of salt and antifreeze to constant volumes of water and determine the freezing temperatures of each one.  You should also want to calculate the molal concentration of each one and try to determine before hand what the freezing points should be (hypothesis).
271556
In addition to the fact that at 4 degrees celcius, water has an absolute density of EXACTLY 1 g/cc, at 0 degrees, it is in equilibrium with its solid phase (ice) which has a density of LESS than 1 g/cc due to its open cage like crystal structure. So, its exact density at 0 degrees is impossible to standardise.