One Stop GATE Forum: EVAPORATION

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    Consider a drop of water on a table. U cant find it after some time. Because it evaporates. But for water to evaporate at a pressure of 1 bar its temperature should increase to 100 degree centigrade. Then why did the water evaporate 

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manju Senior Member Joined: 20Feb2007 Online Status: Offline Posts: 221	Topic: EVAPORATION Posted: 22Feb2007 at 10:18am
	Consider a drop of water on a table. U cant find it after some time. Because it evaporates. But for water to evaporate at a pressure of 1 bar its temperature should increase to 100 degree centigrade. Then why did the water evaporate Post Resume: Click here to Upload your Resume & Apply for Jobs

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balu Senior Member Joined: 20Feb2007 Online Status: Offline Posts: 236	Posted: 22Feb2007 at 10:20am
	Evaporation is a surface effect. The temperature of a body of water represents an AVERAGE value of the kinetic energy of the water molecules in the water. Some of those molecules have a "higher than average" kinetic energy and break free of the surface to become water vapor. As this happens over time, the remaining body of water becomes slightly cooler (as water molecules with higher kinetic energy have "left"). That is why sweat evaporating from your body provides a mechanism to cool you off.
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