Open water

We have had a very cold week, with temperatures never getting above freezing most days. So I was a bit surprised that a good portion of Lake Banet was still open water. (The black dots on the ice are geese.)

I know it is a very deep lake, though I do not know how deep it is. The large volume of water is probably what is keeping it from freezing over.

Water is a very strange substance. Most liquids get more dense as they cool, and they are even more dense when they solidify. Water acts normally until it reaches 39 degrees--it gets more dense as it is cooled. However, as it cools beyond 39 degrees, it gets less dense, and when it turns solid, to ice, it gets less dense yet. Hence, ice floats. You may take it for granted, but that is weird. The bottom of a frozen-over pond will usually be about 39 degrees. Water that is warmer than that will rise and be cooled.