PaPond, Bruce, Wood, Pottsy Cecil and others; Please educate me. I'm in Texas and, around here, ice is something that is usually manufactured and water doesn't often get down to 39 degrees except on the edge of a body of water. Your post says that water rises at 39 degrees and real obviously freezes in your part of the world when it gets to the surface. By itself, that makes sense.
However, my ignorance is why the cooler water doesn't sink. I am assuming (dangerous, I know) that water, like air, rises when warmed and falls when cooled. That is why the bottom of my pond is cooler than the top and,to some degree, why we have thermoclines. Now, there is something real basic here that I don't understand. If that rule were always true, ice would be on the bottom of the pond. I realize that statement is an exaggeration and assume that air trapped in freezing water keeps it more buoyant. It seems that 33 degree water would flee from the surface to always be replaced by warmer water. I guess it also begs the question of why water "layers" as in a thermocline. Surface water temp is obviously influenced by air temp. It appears that water should constantly be mixing and a thermocline shouldn't exist. Thanks in advance for answers that most Texans have never had a reason to ponder.
Hey Wood, we have a cold front or what we call a Norther coming in tonight. The temp will plummet about 25 degrees to the 50'sF during the day and will get down to freezing during the early morning. Sure hope it doesn't last long.
