The process of conversion of a substance from liquid to gaseous state is called evaporation. When water evaporates we obtain the gaseous form of water, commonly known as steam. This conversion process is endothermic, that is it needs an energy input. This supplied energy raises the temperature of water to its boiling point and a part of it is required for phase change (from liquid to gas) and is called latent heat of vaporization. Production of steam has important consequences for human beings, after all it is through conversion of water to steam that we obtain most of our electricity. Whether we think of a coal-fired thermal power plant or a nuclear power plant, in either of them, water is converted to steam which rotates the turbines and generates electricity. The same process was also used in locomotion (coal-fired engines).
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