Below 4° Celsius, water becomes much less dense as it gets colder, resulting in water about to freeze to float to the height. Public Domajor Image, source: Christopher S. Baird. Data source: CRC Handbook of Chemistry and Physics.

You are watching: Why does ice stay at the top of oceans instead of sinking to the bottom?

Warm water primarily gets even more thick as it gets chillier, and also therefore sinks. This fact may lead you to believe that ice must create on the bottom of a lake first. But a funny thing happens to water as it gets even cooler. Colder than 4° Celsius (39° Fahrenheit), water starts broadening and becomes much less dense as it gets colder. As a result, close to freezing, cooler water floats to the height and the warmer water sinks to the bottom. The density of water as a duty of temperature have the right to be viewed in the plot on the ideal. Eventually, the coldest water, which has actually floated to the height of the lake in winattempt problems, freezes to form a layer of ice. Right as soon as the water freezes to ice, the ice becomes substantially much less thick than the water and also proceeds to float on the lake"s surchallenge.

Ice is less thick than water because of the way it develops a hexagonal crystalline framework. Each water molecule consists of two hydrogen atoms bonded to the bottom of an oxygen atom. When ice creates, the hydrogen atoms of one water molecule form weak hydrogen bonds with the height of the oxygen atoms of two various other water molecules. Lining up the water molecules in this pattern takes up more area than having them jumbled randomly together (as is the instance in liquid water). And bereason the exact same mass of molecules takes up even more room once frozen, ice is much less dense than liquid water. For this very same factor, water below 4° Celsius becomes significantly much less dense as it gets chillier. Cshed to freezing temperatures, the molecules in the liquid water begin to line up into the space-filling hexagonal framework.


In the winter, temperatures in a lake acquire cshed sufficient to freezing that the cooler water is less thick and also floats to the height. Public doprimary picture, source: Christopher S. Baird.

See more: What Are The Basic Building Blocks Of Matter Are Called, Atoms Flashcards

The textbook River and also Lake Ice Engineering by George D. Ashton claims, "As a lake cools from above 4° C, the surconfront water loses warmth, becomes even more thick and sinks. This procedure continues until all the water in the lake is at 4° C, once the density of water is at its maximum. With further cooling (and also without mechanical mixing) a stable, lighter layer of water develops at the surchallenge. As this layer cools to its freezing allude, ice starts to create on the surchallenge of the lake."

In deep lakes, water press might likewise play a duty. The gravitational weight of all the water better up in the lake presses dvery own on the water deep in the lake. The pressure allows the water near the bottom of the lake to get cold without broadening and also increasing. Due to the fact that of the push, the water at the bottom of deep lakes deserve to come to be cold without freezing to ice.

Topics: density, freezing, frozen, ice, lake, lake ice, water, weather


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