Hydrosphere Contents

2. Properties Of Water

Heat of vaporisation

The heat of vaporisation is the amount of heat energy required to convert water from its liquid form into a gas or vapour. Likewise, in the reverse process, it is the heat released when vapour condenses to form droplets. Water has one of the highest known heats of vaporisation, making it very important in the transfer of energy between the atmosphere and the ocean. For example, it is the mechanism whereby hurricanes and other tropical storms obtain their tremendous destructive energy. It also represents a mechanism which helps to moderate the extremes of the Earth and makes it a suitable place for life to develop.

Satellite image of a tropical storm.

What is the heat of vaporisation of water and why is it significant?