: How does a fan work against the heat?
In: Other
Haha this is SUCH a frequent question here.
Tldr your body is warmer than air. Thin body temp air layer surrounds you. Fan blows that away so you get new cooler air to surround you. Btw fans dont work when air is hotter than your body’s temperature, then opposite happens and fan will heat you up
Edit: your sweat also plays a role so fans might work even when air is warmer than your body but if theres a certain amount of heat and moisture in the air the fan will do the opposite of cooling you.
A fan doesn’t actually cool the air, it simply moves it around. But that has two effects when it blows on you. Firstly it blows away the layer of air that has been warmed by your body heat and replaces it with cooler air in the room. Secondly it allows more evaporation from moist skin, again blowing away the air that has picked up moisture and replacing it with less saturated air that can take up moisture by evaporation. The process of vaporization requires heat to change liquid to gas, which comes from your body which therefore loses that heat.
The first effect works for any hot body, e.g. the microprocessor in your computer. The second only applies to wet things and if the air isn’t already saturated with moisture, so it is less effective in a 100% humidity situation.
In order for something to get colder, it has to dissipate it’s heat into something else. By passing more air across a surface you can dissipate more heat than if the air is still.
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