Entropy and Thermodynamics

Question: It takes an input of energy to convert liquid to vapor, thus 
increasing entropy.  If an increase in entropy is natural, why does this not 
happen naturally with less effort on its own?
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Actually, if you put a bowl of water in a room that was 
completely empty (no air either - although really the main condition is that 
there be no water vapor in the room to start with) then the water actually 
does naturally evaporate until there is a balance between the amount of water 
vapor and the temperature of the water (basically, it has a natural "vapor 
pressure" that it tries to achieve, for any given temperature).  If the room 
is big enough, all the water will evaporate with no additional energy input.  
Depending on the circumstances, the average temperature of the water will also 
go down in this process, although that is a somewhat separate issue.  The
higher the water temperature, the higher the vapor pressure.  There is 
actually a concept called "free" energy, which takes into account the entropy, 
so that any system tries to minimize its free energy - there is a balance 
between maximizing entropy and going into a higher energy state (the vapor as 
opposed to the liquid) - the whole field of thermodynamics is based on 
understanding these rather complex relationships.

A. Smith
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