Quizzes & Puzzles26 mins ago
how do fans work
floor fans, how do they actaully make you cooler. is it to do with increasing the amount of evaporation from your body by removing heat as soon as it is evaporated, or is it to do with simply blowing cold air onto the surface of your skin thus cooling by removing you body heat by radiation; but surely if this was the case then if the room contained only warm air, the fan would not work??
Answers
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For more on marking an answer as the "Best Answer", please visit our FAQ.The reason for cooling is to do with evpouration but not as mush to do with a pressure drop.
Moisture on the surface of you skin has a few molecules in the vapour above the liquid, this is a state of equilibrium wich has to be maintained. If the surface layer of moist air is removed more water will eveouprate, but to do this it needs energy. The energy is drawn form you as heat (so you feel cooling).
You can make ice by bubling air through ether in the same way.
But what if your not sweating? Granted, there is still a lot of moisture on your skin; however,
one of the major reasons sweeping air across the surface of your skin cools you off is because of
turbulance. Turbulance promotes heat transfer. Since heat energy always flows from hot to cold, as long as there
is any temperature difference between the ambient air and your skin temperature (usually the case), turbulance from
fanning yourself will always increase the rate of heat transfer. If you are sweating profusely this affect will be increased
drastically by the moisture evaporating into the air, which is also increased by the turbulence.