Why don't oceans freeze over in the Winter?

Answer 1

The H2O molecule is a dipole (it looks kinda like this: o: the "o: is the oxygen atom, and ":" is the two hydrogens) Since the hydrogens sort of cluster on one side, and oxygen is more electronegative than hydrogen, the left-hand side of this diagram would have a partial negative charge, and the side with the hydrogens would be slightly positive. The slightly positive end of one water molecule will "bond" with the slightly negative end of another water molecule. Like magnets. This occurs to some extent naturally, becasue it takes less energy to just let two magnets stick together than it does to hold them a centimetre apart, right? So when the temperature outside drops, more hydrogen bonds are formed, which conserves the energy of the molecules, allowing them to remain in liquid phase. (this is, in fact, the same reason water crystallizes in such a wierd way when it's freezing, making it LESS dense as a solid.) Likewise, it takes water longer than most other things of comparable molecular mass because, as heat is added, hydrogen bonds break and molecules take on energy instead of buzzing around and evaporating.

Answer 2

The oceans are saline or salt water. This affects the temperature at which they freeze. Plain water freezes at about 0°C at sea level, but saline, at the concentrations normally found in the ocean, freezes at close to -2°C. Pressure also affect freezing temperature. The deep ocean is at great pressure, so even though it can be at temperatures of -3°C it does not freeze.

The temperature of the surface of the ocean varies from about -2°C to about 34°C depending on currents and latitude.

Much of the surface of the Arctic ocean is frozen all year round, but the extent varies during summer and winter. An area of the sea around Antarctica also forms sea ice in winter each year, but much less area is permanently frozen than in the Arctic.

Answer 3

Most lakes actually do. Larger lakes generally will not freeze over because of movement. The water doesn't quite get cold enough to actually freeze. It's the same principle behind why the ocean doesn't freeze. It only does at and around the poles.

Answer 4

Because the pressure lowers the freezing temperature along with the salt content