Question

Observe the following graph. Considering the change in volume of water as its temperature is raised from 0°C, discuss the difference in the behaviour of water and other substances. What is this behaviour of water called?

Answer 1

Most of the substances expand on heating and contract on cooling. Whereas, from the graph, it is clearly visible that water shows a distinct and peculiar behavior between 0^oC to 4^oC. Water, instead of expanding, contracts between 0^oC to 4^oC. After 4^oC, it shows the normal behavior of expansion as is shown by other substances. Thus, at 4^oC, water posses maximum density and minimum volume. 
This behavior of water between 0^oC to 4^oC is known as anomalous behavior of water.