Why does a fan feels cool?

Question

Even when our bodies are completely dry we sit under a fan we feel colder, why

Answer 1

Because you are warmer than the surrounding air.  forcing more air past you increases the heat transfer from you to the surrounding air.

Answer 2

u r no only sweating when sweat drips from ur body

in general too we have sweating in small amount that is not visible. hence then our sweat evaporates and we feel cool

Answer 3

What a fan does is create a wind chill effect.

When weatherpeople talk about wind chill on a cold winter day, what they are referring to is how the wind increases convective heat loss (see How Thermoses Work for details on convection). By blowing air around, the fan makes it easier for the air to evaporate sweat from your skin, which is how you eliminate body heat. The more evaporation, the cooler you feel.

Answer 4

Heat transfer from a body into air is mainly dependent on the air speed at the surface of the body.

The fan increases air speed and therefore the heat is transfered more efficiently.

From our bodies, heat is transferred mainly by three processes:

1) radiative heat (not affected by the fan)

2) heat loss by convection to surrounding air - this process only works if the air is cooler than your body, so it will not work when it is very hot. this process is helped by increased airspeed.

3) heat loss by evaporation. As we swet and breath, water evaporates from our body in to the surrounding air. This process works EVEn when the air is warmer than our body and increases efficiency with increased airspeed.

However, this process will not work if the air is already saturated with moisture. That is why moist heat, such as in West African countries, is the most unconfortable.

The same process of evaporation works on clothes when they are drying out in the washing line. On a windy day they will dry quickly, even if it is not hot or sunny.

Answer 5

It is still evaporation, a "dry" body still has some level of surface moisture.

Assuming your skin was actually dry, which would be a very bad thing. You still would be cooled by conduction, since your body is hotter than the air the heat from you body will flow into the surrounding air seeking equilibrium.  It is one of the basic laws of thermodynamics.  In this case the fan will move the recently heated air away and push cooler air near you skin to maintain an imbalance and continue the conduction.

Answer 6

because when it spins it makes wind in front mixes with vapour in the air so it makes it makes the vapour push and hits you so it cool air. I Think!