why does the volume of water increase when it freezes and becomes ice?
405635
water (H2O) arranges itself into a crystalline structure when frozen (a hexagon) (why snowflakes have six points) the two hydrogen and one oxygen atom forming a triangle.\nthis structure occupies more space than when randomly flowing in liquid state
208915
With most substances high pressures help it form from gas to liquid to solid.  But with water high pressure between liquid and solid the transition is harder to make happen.  This is due the expansion of water when freezing.
169888
Yes, it does.  This is evident by water freezing in enclosed containers (such as pipes) and deforming them, sometimes even rupturing them.  \n\nWhen water molecules become cold enough to freeze, or change into a solid form, their crystal structure is less dense than when in liquid form.  This is due to the inherent shape of the water molecule and how the molecules line up in solid form.\n\nIf you live in a colder climate, it's a standard procedure to drain any remaining water out of things kept outside over the winter, such as boats, swimming pools, outdoor water pipes, etc.  Otherwise you can almost expect them to be ruined by the time you want to use them again.
199577
ok, guys.  both v_dawg and quicksilver are right.  when water makes a phase transition from liquid to solid (freezing) it expands in volume; that's why bottles filled with liquid will crack in the freezer.\n\non the other hand, if you leave it sitting there for a while, there will be a slow phase transition from solid to gas (sublimation) and over weeks-months the ice cubes will noticeably shrink in size.
1036867
Of course ice and water are chemically identical consisting of H2O.  The two hydrogen atoms attach to the oxygen atom other than in a straight line (not like beads on a string).  The electron field surrounding the water molecule is uneven providing it with a "polarity" that makes it much easier to pack many molecules together in a given (rather than arbitrary) arrangement.  When water is a vapor (or steam) there is so much vibrational energy that the molecules bounce off each other maintaining a "pressure" depending on their energy (temperature).  When the molecules are a liquid, they are very closely packed and are nearly incompressible (even seven miles below the surface of the ocean!).  The bulk water expands and contracts only a little with temperature changes.  When heat is removed from the water (in a freezer?) the molecules are attracted to each other in a preferred array due to polarity and form long chains of molecules that use up space far less efficiently.  The "ice" is less dense and floats on water because the space between chains is filled with a vacuum or gases that weigh very little.  When the water is allowed to freeze in open space (a cloud?) the polarity is free to align water molecules in the most preferred orientation; a six sided snow flake.  When hoar frost forms on a cold window pane the ice forms in dendrites, like growing Christmas trees.  Hope that helps a little.
304553
water becomes more disordered as it freezes which is why it expands. the second law of thermodynamics states that without an input of energy things tend toward disorder (entropy) or results in "anarchy" as the saying goes. as most liquids solidify they become more orderly and less random which is the exact opposite of what happens with water thus water defies one of many natural laws.
118956
Liquids expand when they freeze.
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.
353678
The water droplets are very tiny and present a lot of surface area (compared to their volume) to the air. Rapid evaporation from the surface of the droplets cools them sufficiently to freeze.
549327
Freezing water expands.
279129
the density of water is 1 gm/cc.however the density of ice is less than 1gm/cc.this means that d density of water of water increases when it changes to ice.this is known as anomalous expansion of water.
472454
During winter the water at the surface of lake or pond gets cooled.\n\nDue to cooling density of water increases; denser water\ngoes down, while the relatively hot water comes up. This is convection.\n\nBut water has a peculiar property that below 4 degree C it becomes less dense.\n\nTherefore when the surface temperature is 4degree and below, the water at the surface cannot go down. Hence convection of water is stopped. \n\nThe temperature increases relative to water surface.  If the temperature of the water surface reaches freezing temperature, ice is formed on the surface and the freezing takes place from top to bottom.\n\nThus lives of water living creatures are saved from freezing.
527105
Water when frozen, expands.  it is less dense. so it floats on water which is more dense.
313475
The primary reason water expands upon freezing is the breakage of hydrogen bonds.  The hydrogen bonding which occurs in the polar water molecules acts to bind water molecules closer together than they would otherwise.  When freezing, though, those hydrogen bonds must break in favor of the crystalline solid structure (which packs the molecules less densely).  Hydrogen bonding also leads to the extremely high boiling point of water for such a small molecule (most molecules of small molecular weight are gases at much lower temperatures than 100 deg C).\n\nIn fact, hydrogen bonding contributes to just about every unusual property of water.  There are very few molecules in nature that exhibit hydrogen bonding; and none, to my knowledge, exhibit it as strongly as water.  Alcohols have some hydrogen bonding, which is why they have higher boiling points than other, comparable molecular weight organics.
314279
The reason that water expands upon freezing is because of the strong hydrogen bonding between the water molecules. Water is polar having a positive end nearest the Hydrogens and a negative end nearest the Oxygen atom. Therefore The positive ends of some water molecules attract the negative ends of other water molecules. When water reaches 4 degrees Celsius the molecules have been pushed as close to one another as they will be. Below 4 degrees the water molecules begin to align themselves into the crystal structure of ice. This requires the water molecules to widen the angle between the Oxygen Hydrogen single bonds . When this happens the water molecules take up more space hence expansion.
227694
In pure water, the molecules particpate in Hydrogen Bonding; positively polarized hydrogen nuclei are attracted to negatively charged electron clouds. \n\nThese hydrogen bonds hold water molecules together in the liquid phase and so explain why water expands, rather than contracts, when it freezes.\n\nWhen glucose is added to water it interferes with the hydrogen bonding. Effectively, a proportion of the bonds are broken. It requires energy to break bonds (think of breaking a twig--you have to put some energy in to the twig to break it) and that energy has to come from somewhere: it gets sucked out of the immeadiate environment--the glass.
530819
Com'on people, you should know this.\n\nPut in the ice cube slowly, some water spills out, most of the ice is under water (about 92% due to lower density).  Ice melts in time and the water level drops very slightly due to: 1) water temperature drops a bit (higher density, lower volume), 2)evaporation.