Why does air blown by a fan feel colder than the other air in the room?
In: Physics
You are not comparing the average air in the room with what is blown by the fan. You are comparing the air close to your skin with the air the fan blows.
If we assume the air temperature is below you body temperature then you heat up the air around you. The air in the rest of the room will be colder. The fan replaces warmer air around you with cooler air around you.
If it is warm and you sweat the air close to you will have a higher moisture content than the rest of the room, so the fan replaces it with air with lower moisture content. This means the sweat evaporates faster and that cools you down.
If you were in a room where the air was warmer than your body temperature then you cool down the air close to you, When the air heats you up it gets colder. So the fan will replace cooler air with warmer air.
If it feels warmer or not will depend on the moisture content, if it is dry air sweat on your skin can evaporate and that cools you down. If the air is saturated with water the sweat will not evaporate and you feel warmer. An example where you can have air warmer than you that is very moist is in a sauna, then a fan heats you up
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