In a hot night, inside a room with no windows but one door the temperature inside the room its causing me to sweat even when I'm naked resting on the bed. The fan is on. According to physics. Why the air produced by the fan is cold? Why the air is not warm as the surrounding environment?

Question

anonymous · Answer

To the best of my knowledge and I'm not a physics guy, so feel free to correct me. The air is the same temperature. the reason it seems cooler is the moving air allows your sweat to evaporate giving a cooling sensation as your body cools.

anonymous · Answer

That is exactly the answer, and can be demonstrated by comparing blowing on a wet finger compared to a dry finger.  

Also bear in mind a smaller effect, that unless you are living in the tropics, your body temperature will be higher than the air of the room.  Air immediately next to the skin will be heated by your body.  Without a fan it remains close to the body, when the fan blows it will move that volume of heated air away, replacing it with slightly cooler air, from the rest of the room.

There is an even smaller effect though.  The faster a volume or body of air flows over a surface (with respect to the surrounding air), the lower the pressure of that body of air (known as Bernoulli effect, and responsible in part for flight, and curling footballs in sport).  For an ideal gas of constant volume, $PV \propto T$, so if pressure $P$ decreases, so too will the temperature $T$

anonymous · Answer

What about this?

p.V/T = Po.V0/T0

anonymous · Answer

Essentially taht is just a different way of stating what I stated above above with teh ideal gas law.

anonymous · Answer

Thank you.