Question

What is anomalous expansion of water

Answer 1

Anomalous expansion of water: water has a unique property of anomalous expansion. When water is cooled from room temperature it first contracts in volume and becomes increasingly dense as do other liquids, but at 4° C water reaches its maximum density. On further cooling it starts expanding and become less dense. This will be continued till the temperature reaches 00C, the point at which it freezes into ice.
This unusual property of water enables marine life to exist in the polar region where temperature falls below freezing temperature. The outer layer of water becomes ice and floats over the water. As the water has highest density at 40C sinks down and keeps its aquatic life in safest position

Answer 2

The anomalous expansion of water is an abnormal property of water whereby it expands instead of contracting when the temperature goes from 4oC to 0oC, and it becomes less dense. The density becomes less and less as it freezes because molecules of water normally form open crystal structures when in solid form