Why does water attain its maximum density at 4 degrees Celsius?

Answer 1

Water attains its maximum density at about 4°C because it is at that temperature that hydrogen bonds form. The effect of the formation of these bonds is that molecules of water are actually pushed apart and into an alignment scheme (crystals) that prevents them from more closely packing together as in the liquid state.

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Answer 2

At any temperature, water molecules have some thermal motion. The thermal motion of molecules causes some expansion of the volume. When water is cooled to about 4 0C, the water molecules have almost reached their lowest thermal motion and are thus very dense, but still have just enough motion to prevent organization into hexagonally-organized crystalline ice. Below 4 0C the water molecules tend towards the hexagonally organized structure of ice and thus the volume expands a bit, reaching its minimum density when the ice forms.

Answer 3

This is special characteristics to water. Although in liquids, generally, the liquid density increases with temperature decrease but in water when temperature decrease from 4 to zero (water freezing into ice) the density decreases. This results in Ice formation in rivers and polar areas and its floating to the surface because of its less density than water keeping water underneath at 4 degrees which is enough for aquatic species to remain alive in water while the ice on the top is acting as insulator.
-ELO-
As water begins to freeze, the molecules must spread out to form latices of ice.

Answer 4

When water cools from room temperature (21C) to 4C it gets more dense due to thermal contraction. Then between 4C and 0C it expands rather than contracts and becomes less dense. This is a molecular oddity. At 0 C it freezes and expands even more, becoming even less dense. That is why ice floats on water

Answer 5

When water freezes, air bubbles form and it becomes less dense.

Answer 6

it is at its max density at 3.98 degrees centigrade because it is the temp at which hydrogen bonding takes place.

Answer 7

GOD KNOWS!!

ask him!!

Answer 8

It is supposed that strong intermolecular interactions are involved for this anomaly.