# thermodynamics in air and water

In perspective of thermodynamics,a person can survive a temperature of twenty degrees Celsius in air, but a person cannot survive in water with same temp.(it's not because he can't breathe) why is that in perspective of thermodynamics??

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The main reason you lose heat faster in water than in air is that it has a much higher specific heat. The specific heat of water is 4.2kJ/kg and the specific heat of air is about 1kJ/kg. However the important figure is really specific heat per unit volume because it's the volume rate of the flow around you that matters. This is 4.2MJ/m$^3$ for water and about 1kJ/m$^3$ i.e. a water flow extracts about 4,000 times as much heat from you.