This isn't so useless, it's evidence for creation:
Water is the only substance, that in liquid form, freezes from top to bottom. All other liquids freeze bottom to top. If this were not so, ever winter, the rivers and polar bodies of water would completely freeze through, killing all the fish and other creatures underwater.
The top layer of ice on water protects the water underneath from the cold air, keeping it from freezing completely through (unless it reaches amazingly low temperatures, of which most fish couldn't live through the water temperature before it iced over anyway)