Why does a lake freeze from the top to down?

Answer 1

because the earths heat revolves in a circle, hot on bottom and cold on top. when the lake freezes the coldness freezes the cold first and takes a longer time freezing the hot(bottom) because it is warmer.

Answer 2

Ice, being frozen water, is one of the few things that actually expand when frozen. Since it expands, it is less dense than the water, therefore floating. It forms on the top because that is the most exposed to the cold.

Answer 3

One of the unusual properties of water is that it is actually less dense when it turns from a liquid to a solid - hence the reason ice floats on water. In its liquid phase water is actually at its maximum density at around 4 degrees C and then undergoes a slight decrease in density towards 0 degrees (then a large decrease upon freezing).

This means that water at 4 degrees C is more dense and will tend to sink below water at a lower temperature. As such water less than 4 degrees C will float on top of the slightly warmer water and will be nearer the surface of the pond and so will freeze first.

Answer 4

It's because ice is less dense than water, therefore it floats, this helps the species of the lake survive in winter time because the ice acts as an insulator.

Answer 5

Water expands when it freezes, therefore it is less dense and floats to the top. The ground can also sink coldness away from layers of water on the bottom of the lake.

Answer 6

because ice is less dense than liquid water. Water expands as it freezes so, even if it started freezing at the bottom, the ice would flow up to the top.

Answer 7

Because water is heaviest at +4 degrees centigrade, and lighter as ice.

Answer 8

The cold air hits the top first and makes its way down