When lakes/ponds freeze, how come only the top layer is frozen and there is still water underneath? Yet when you put a bowl of water in the freezer, the whole thing is one solid block of ice.

Question

This probably has an obvious answer and something is just not clicking for me.

In: Chemistry

Answer 1

Ice is actually quite a good insulator, meaning it’s bad at conducting heat. It takes a realllllly long time for ice to conduct heat from the water underneath it to the cold air on top.

In a freezer, you only have a small amount of water. It’s easy for the freezer to efficiently and continuously remove the heat from the water until it all turns into ice. Some lakes and ponds *do* freeze all the way, but if there’s enough water, there’s so much heat that the cold air just can’t remove it all through the layer of insulating ice before the spring thaw comes.