Why does water expand when its cold?

Question

All other material contracts when its cold.

Answer 1

it does expand for a while. from about +4 celsius to 0 celsius. then it contracts after that as the temperature gets very cold. It has to do with how the elements fuse together to form a solid and then after the solid if formed (ice) then the process of shrinking occurs normally as the shrinkage seen in other materials

Answer 2

Thank you for asking a most interesting question.

The most authoritative source of info on the properties of water can be found in Wikipedia. I lift this extract to answer your question :

A simple but environmentally important and unusual property of water is that its common solid form, ice, floats on its liquid form. This solid phase is not as dense as liquid water because of the geometry of the hydrogen bonds which are formed only at lower temperatures. For almost all other substances the solid form has a greater density than the liquid form. Fresh water at standard atmospheric pressure is most dense at 3.98 °C, and will sink by convection as it cools to that temperature, and if it becomes colder it will rise instead. This reversal will cause deep water to remain warmer than shallower freezing water, so that ice in a body of water will form first at the surface and progress downward, while the majority of the water underneath will hold a constant 4 °C. This effectively insulates a lake floor from the cold. The freezing point of water is 0°C (32°F, 273 K).


For more info, see link below.

Answer 3

At 4°C water contracts as it is at it's maximum density, compared to at 25°C (so it depends on your definition of cold), however once it is frozen it expands because the hydrogen bonding becomes ordered and that expands the structure so there is more gas between the water molecules. (This is also why ice floats).

Answer 4

Below freezing point the water molecules have no chance to be converted into steam. Since, water is an amphoteric compound, it has to compensate between the equal but opposite charges to its content. So, the interatomic space widens as a result of repelling forces between like charges. Thus, the water in whole in the ice form expands.

Answer 5

Water expands as it freezes, as air pockets get trapped between the ice crystals and therefore it expands.

Water is an example of Hydrogen bonding - so H2O is in its most compact state as a liquid.

There are other materials which are also larger when solid, I think Antimony is one and Bismuth the other.

Answer 6

When water freezes, it adopts a curious crystalline structure. The crystal arrangement doesn't pack the molecules as closely as they are packed in the liquid form. Therefore, ice is less dense than water. That's why ice sheets and icebergs float. Other substances have higher densities as solids, but water's crystal arrangement is unique.

Answer 7

Because of the shape of the water molecule. When they line up to connect when cold they take up more space then when they are warm and can move around.

Answer 8

The reason is so that the planet doesnt die off. I personally think the fact that ice floats is the clearest, most intuitive proof that God exists.

Answer 9

Because it is a liquid changing into a solid.

Answer 10

It gets more solid.