Phases of Water
The state of water can be changed from gaseous to liquid and liquid to solid and vice versa by the addition or removal of heat energy. To convert one gram of liquid to ice requires the removal of 80 calories of heat energy. To convert one gram of water into steam requires an input of 540 calories of heat energy (Figure shown below). Change of liquid water into steam involves the breaking of hydrogen bonds which normally join the adjacent water molecule.
Accordingly, a very large amount of heat energy is needed for the evaporation of water. This property of water is extremely helpful in moderating the earth's temperature and making it suitable for origin and continuance of life.