Latent Heat

Concerning lake ice overflow, how does the liquid water, trapped between ice and snow remain liquid for weeks at a time. It seems that water trapped between two frozen layers would freeze quickly.
- Terry (age 58)
Big Lake, alaska, use

In order for that liquid water to freeze, it doesn't have to just get down to 0°C. It has to get rid of the extra energy (enthalpy, for purists) that the liquid has above what the solid has, the "latent heat of freezing".  This energy is carried away as a heat flow in the surroundings. However, heat conduction in ice and snow is slow. So the water freezes slowly.

Mike W.

(published on 11/03/2011)