Oct 2007: Water in a lake freezes from the top down. Water is most dense at 4 degrees Celcius, and the entire lake must get to that temperature before the top freezes. Snowflakes mix with salts and remain snow even upto 10 degrees Celcius. Taught in primary school, but still continues to fascinate. The snow in this picture may be warmer than lake water, and water may be denser than the snow pack.









