"why do water pipes burst in very cold water"?
552808
Write your own essay...but water freezes when it is cold and becomes ice which expands causing the pipes to burst, that's why they need lagging/insulating to prevent this happening.
792394
Because although the temperature is very low, the pressure is essentially zero (<< 1Pa). Nothing to do with gravity.\n\nReducing pressure reduces the boiling point.\nHowever below T=273K ,P=10^3 Pa, water goes cannot exist as liquid, it goes directly from ice to vapor.\nThis is what the phase diagram of water describes (see graph):\nhttp://en.wikipedia.org/wiki/Phase_diagram\n\nSo the water will evaporate and then sublime to ice almost immediately as its temperature goes below 200K.\nThe ice is going to be in form of microscopic dust because the vapor molecules dispersed due to the zero pressure.\n\nThis diagram is actually clickable, so you can click on the phases and phase lines to see their curve-fit and coefficients.\nIn this case, go to bottom left (low P, low T) you can see the ice-vapor line from (P=0,T=200K) to (P=10^3Pa,T=273K)..\nhttp://www.lsbu.ac.uk/water/phase.html
291269
Cold water has more dissolved gases in it than hot water.  Any dissolved solutes cause the freezing point of water to be lower than pure water with nothing dissolved in it.\n\nThis means if your power goes out in the wintertime and it is about 32 degrees F outside, the water in your hot water pipes is more likely to freeze than the water in your cold water pipes.  This is because the freezing point of the water in your hot water pipes is higher than the freezing point of the water in your cold water pipes.\n\nSpeed isn't being considered here.  The cooling process is assumed to be slow so that the pipes are in thermal equilibrium with surroundings.\n\nAlso check out this link.  It is from the Alaska Science Forum.  They can explain the water pipes problem more correctly than me and they have more personal experience with the phenomenon.\nhttp://www.gi.alaska.edu/ScienceForum/ASF4/440.html
747796
Because the air is so thin, it has so little heat that water cannot exist as a liquid.  In other words, thinner air means colder temperatures, but that's kind of oversimplified.
777760
Water pipes are getting unreliable as a lot of the main pipes are being replaced with non-metallic pipes. An earth rod is really the only reasonably certain earth. If you earth onto structural metal there is a chance that the metal may not earth and become live  if a fault occurs
319184
if the cold thing is cold and crystaline, like pyrex or ice, the object cracks because of rapid localised expansion.\n\nIf it is really really cold, the water will crystalise.\n\nIf cold water hits something hot it forms little drops with a protectice steam jacket and they bounce around for ages, a cool experiment for home on a hot frying pan. (only uses drops of water though)
537854
Artificial rinks can  be made in cold climates by enclosing a level area of ground, filling it with water, and letting it freeze.\nWith the pipes cold, a thin layer of water is sprayed on the sand or concrete to seal and level it (or in the case of concrete, to keep it from being marked). \nThis thin layer is painted white or pale blue, for better contrast; markings necessary for hockey or curling are also placed, along with logos or other decorations. \nAnother thin layer of water is sprayed atop this. \nThe ice is built up to a thickness of 2-3 centimetres by repeated flows of water onto the surface. \nPeriodically after the ice has been used, it is resurfaced using a machine called an ice resurfacer. For curling, the surface is 'pebbled' by allowing loose drops of cold water to fall onto the ice and freeze into rounded peaks.
1078588
yes the glass would break because unlike any other liquid water expands when frozen therefore the glass would break regardless of how full it is
260171
It isn't air! When water freezes all dissolved gases & other matter are not included!!! \n\nThe hydrogen bonds that form when water freezes creates an open structure. There is simply nothing in between those spaces.\n\nWe are talking about molecular structure, things at this level are so tiny that even thinking about what is in between is silly.\n\nIf there is anything between the spaces it is probably interstitial water molecules (those not hydrogen bonded inside the crystalline lattice structure - think of them as loose molecules of water).\n\nIce floats on water because it has expanded. That is all. Not because of what is in between the "spaces".\n\nSee, when you increase the surface area but have the same number of molecules present, you cause the object to become less dense. (it's less tightly packed...things that are tightly packed for their size are said to be more dense.)
434026
If you place a glass of hot water in an ice box it will actually freeze faster than a glass of cold water. \n The reason is that the temperature difference makes the water circulate in the warm glass transfering the heat loss evenly through the contents, in cold water the outside freezes first which insulates the inside from heat transfer keeping the center liquid.\n Try it, you'll see.
288935
Fresh water freezes when the temperature of the water is 32*F and the pressure is normal atmospheric pressure. And then, if there is a heat loss for that fresh water, then it would freeze at lower pressures also. \nIf ice is at 32*F and there is a heat gain, it would melt at 32*F. Also, if at 32*F with no heat flow there is higher pressure, then ice would melt. (eg skiing. If you put your pressure on the skis, the ice/snow melts and becomes water so that you can ski)
1119841
The bubbles are actually bubbles of steam, not air.  Because of tiny bumps on the bottom of the pan, there are spots where the water gets hotter than in other spots, and it turns to steam bubbles.  These bubbles collect together and float up to the surface, where they "pop" and actually cool the water down a tiny bit.  This cooler (less hot) water sinks to the bottom, gets heated up into steam again, bubbles form, and so on.  So the bubbles won't boil out before the water is gone, because it's the water itself that's making the bubbles.
166782
The cold water froze about 10 or 15 minutes faster than the hot water, and there was no detectable difference between the boiled water and the other kind. Another old wives' tale thus emphatically bites the dust. Science marches on.
99485
no. because something could be steaming when it is cold.
104094
cold make stuff get bigger but hot water makes stuff constrict
1049421
The problem with that is that water wil freeze below 32 farenheit. so it would need a eletric trace(heat trace to heat it up if temp goes below 32) and insulation to keep the heat in. Also, rusting is a major issue which is bound to happen even if the most rustfree material is used. Also leaks are a major issue. Something chemical has to be mixed with water to determine exact location of the leak if one takes place. the oil pipelines in middle east use a chemical, i forget the name, for the same reason. Adding and removing the compund from water may be a major pain. Also another major problem would be collecting the water, how exactly would that be done. Drainage water maybe, but it would be very very hard to collect pure rainfall and transport it. The idea may seem easy but it would involve major reconfiguration of water systems, water collectors, pipelines within existing eastern cities, etc to provide water to the west. Its just not economical to do so. Also pumping stations to clean water at each interval are also expensive to first build and then run.
335460
. Yes -- here is a general explanation for all you non-belivers.\n\nHot water can in fact freeze faster than cold water for a wide range of experimental conditions.  This phenomenon is extremely counter- intuitive, and surprising even to most scientists, but it is in fact real.  It has been seen and studied in numerous experiments.  While this phenomenon has been known for centuries, and was described by Aristotle, Bacon, and Descartes [1-3], it was not introduced to the modern scientific community until 1969, by a Tanzanian high school student named Mpemba.  Both the early scientific history of this effect, and the story of Mpemba's rediscovery of it, are interesting in their own right -- Mpemba's story in particular provides a dramatic parable against making snap judgements about what is impossible.  This is described separately below.\n\nThe phenomenon that hot water may freeze faster than cold is often called the Mpemba effect.  Because, no doubt, most readers are extremely skeptical at this point, we should begin by stating precisely what we mean by the Mpemba effect.  We start with two containers of water, which are identical in shape, and which hold identical amounts of water.  The only difference between the two is that the water in one is at a higher (uniform) temperature than the water in the other.  Now we cool both containers, using the exact same cooling process for each container.  Under some conditions the initially warmer water will freeze first.  If this occurs, we have seen the Mpemba effect.  Of course, the initially warmer water will not freeze before the initially cooler water for all initial conditions.  If the hot water starts at 99.9° C, and the cold water at 0.01° C, then clearly under those circumstances, the initially cooler water will freeze first.  However, under some conditions the initially warmer water will freeze first -- if that happens, you have seen the Mpemba effect.  But you will not see the Mpemba effect for just any initial temperatures, container shapes, or cooling conditions.\n\nThis seems impossible, right? Many sharp readers may have already come up with a common proof that the Mpemba effect is impossible.  The proof usually goes something like this.  Say that the initially cooler water starts at 30° C and takes 10 minutes to freeze, while the initially warmer water starts out at 70° C.  Now the initially warmer water has to spend some time cooling to get to get down to 30° C, and after that, it's going to take 10 more minutes to freeze.  So since the initially warmer water has to do everything that the initially cooler water has to do, plus a little more, it will take at least a little longer, right? What can be wrong with this proof?\n\nWhat's wrong with this proof is that it implicitly assumes that the water is characterized solely by a single number -- the average temperature.  But if other factors besides the average temperature are important, then when the initially warmer water has cooled to an average temperature of 30° C, it may look very different than the initially cooler water (at a uniform 30° C) did at the start.  Why? Because the water may have changed when it cooled down from a uniform 70° C to an average 30° C.  It could have less mass, less dissolved gas, or convection currents producing a non-uniform temperature distribution.  Or it could have changed the environment around the container in the refrigerator.  All four of these changes are conceivably important, and each will be considered separately below.  So the impossibility proof given above doesn't work.  And in fact the Mpemba effect has been observed in a number of controlled experiments [5,7-14]\n\nIt is still not known exactly why this happens.  A number of possible explanations for the effect have been proposed, but so far the experiments do not show clearly which, if any, of the proposed mechanisms is the most important one.  While you will often hear confident claims that X