The onset of winter has me thinking of ice. Did you ever marvel at the wonder of ice floating? It is because of a property which is, so far as I know, unique to water. As we all learned in school, things contract as they get cooler and expand as they get warm. And so does water – except when it is about to freeze. When water gets to about four degrees centigrade, mystery of mysteries, it begins to expand again. I don’t know if anyone knows why, but it is this expanding that causes potholes in the roads and breaks apart huge boulders. Because it expands at that temperature, water at three degrees centigrade is less dense than water at four degrees, and hence lighter, and water at two degrees is lighter still and even lighter at one degree. Being lighter, water at one degree in a flat surface will be a layer above water at two, which will be above water at one, and at zero, when it solidifies, it will be on top.
What would be the result if water got ever more dense, and therefore heavier per unit of volume, as it got colder and froze. It would not float. The skin of floating ice, sometimes inches or even feet thick in the arctic, shields and protects the water below from further freezing. If the ice didn’t float but sank to the bottom, rivers and lakes and perhaps even the oceans would freeze solid, inhibiting any aquatic animal or plant life. It could mean that the earth could not support any life at all.
So the next time you are in a restaurant and the waiter bring you a glass of tea or water, marvel at the floating ice and the miraculous all around us in everyday things, and be thankful.
Oh, Lord, the earth is so full of miraculous things, I think we should all be as happy as kings. (With apologies to Robert Lewis Stevenson.)
Ron Hicks, Parish Verger, St. Alban’s Episcopal Church, Washington DC, 26-November-2013