A cluster model explaining quantitatively the anomalous variation of density of water with temperature

A model that assumes the presence of cavities and clusters in liquid water can quantitatively explain the anomalous variation of density with temperature. The increase in density from 273 K (0°C) to around 277 K (4°C) is primarily due to the dissociation of H-bonds from the larger clusters. At higher temperatures the thermal expansion of volume leading to a decrease in density plays a dominant role.