5.0 The Expansion of Water

All the liquids expands on heating, except few, like water. The diagram shows how the volume of 1$g$ of water varies with temperature at normal pressure. We can observe that the volume of the water decreases as the temperature is raised from ${0^O}C$ to ${4^O}C$, at that point the volume is minimum and the density is maximum that is $1000Kg/{m^3}$. Then, above ${4^O}C$ the water expands with increasing temperature.

This behavior of water is known as anomalous behavior of water and causes ice to form first at the surface of the lake in the cold condition. As winter approaches, the temperature of water increases initially at the surface, the water there sinks due to the increase in density. Then, the surface reaches ${0^O}C$ first and lake becomes covered with ice, the aquatic life can survive the cold winter as the lake bottom remains unfrozen at a temperature of about ${4^O}C$