Ice is a miraculous substance. Actually, it is water that is so amazing. Ice is just one of its three phases.
Water is essential for life and one of its unusual characteristics is how it behaves when its temperature drops. Like most substances water contracts as it gets colder, but unlike other substances, it reaches maximum density at 39 degrees Fahrenheit and then expands as it gets colder. Finally, when it freezes at 32 degrees Fahrenheit it expands.
That’s huge! If Ice were denser than water, it would sink to the bottom of a lake or pond. The surface would continue to freeze and sink until by mid-winter the lake would be all ice. Few creatures could live there.
Instead, when water freezes it expands and gets lighter. It floats on the colder water beneath and insulates the water, so it doesn’t freeze all the way to the bottom. Ice is merely a veneer floating on water, enabling life in the liquid below it.
It might be 20 below zero in the air above the ice but down in the water a fish basks in the relative warmth of water in the 30s.
When lake ice gradually cools as fall’s temperature drops a beautiful result happens in some years. On one cold, clear, calm night the lake will form a layer of crystal clear ice several inches thick. It’s hard and usually safe to walk on.
The walk reveals amazing patterns of cracks and fractures. Clear ice gives a lake walker the sensation of striding on air with a clear view to the bottom beneath the feet. For an idea of the beauty of ice, enjoy these photos taken at Cedar Lake, Denville, New Jersey, in January 2018.