why do we feel more cold wearing wet cloths before a fan?

Answer 1

Temperature is how we measure the average amount of kinetic energy (movement) of molecules in a substance. The water in those clothes is made of molecules that, on average, are about the same temperature as your skin. But temperature is an average - some of the molecules have less energy, some have more. A few of the molecules actually have as much energy as the average molecule in a sample of boiling water. Evaporation happens when these high-energy water molecules break away from the other water molecules and fly away into the air as a molecule of water gas. That takes their energy with them. The molecules left behind in your clothes, on average, are a little less energetic, meaning they are a little colder. Since they are now just a bit colder than your skin, your skin warms the remaining water by getting a little colder, and you feel that.

This process occurs whether you're standing in front of a fan or in a room with perfectly still air. The reason it feels colder in front of a fan is that the moving air speeds up the process. In perfectly still air, the air right next to your clothes can get pretty full of the water molecules that have evaporated already, and they get in the way of more water molecules evaporating. The more air rushing past your wet clothes, the faster evaporated water molecules are moved out of the way to allow more to evaporate. The faster the evaporation occurs, the colder the water gets.

And that's why your wet clothes feel colder in front of a fan.

Answer 2

Everyone's internal body temp is about 98.6 degrees. Clothes provide insulation to maintain body temperature just as insulation is used on a house. When this insulation is compromised (wet) it's no longer effective. This is why people wear layers to stay warm; it is not the clothes but the air trapped between the clothes acting as insulation. (Ever seen "The Day After Tommorrow" where they stuffed their shirts w/ paper to stay warm....).

If wet clothes are cooled by a fan you can feel the water temperature drop. Which would you rather feel on a hot day: warm pool water (wet clothes) or cold pool water (wet clothes w/ fan); what about on a cold day?

Also, cold objects absorb heat. This is why you feel cold. Consider ice melting when held in your hand: heat is transferred from you (reason why you are cold when touching ice), lowering your temperature and simultaneously raising the temperature of the ice to a liquid.

Answer 3

Evaporation is a cooling process (think sweating). The fan moves the air around and makes evaporation occur at a faster rate. When the liquid evaporates, it absorbs energy from your skin in the form of heat.

Answer 4

Well the scientific reasons are already in others' answers, so I'll just skip to a fun fact:
Water absorbs twenty-five times as much heat from your body as air.
This is why the number one enemy in cold-weather survival is your own sweat. If you exert too hard out in cold weather, and start sweating, when you stop later to rest or sleep your sweat will suck the heat right out of your body as it leaves and you'll be in some serious danger of hypothermia.

Answer 5

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Answer 6

Evaporation of water requires energy from heat.
When water evaporates, heat is removed from the surroundings.
A fan causes water to evaporate more quickly, so it uses up heat more quickly and cools the fabric, our skin, and the air.

Answer 7

Eh, kamu orang Indonesia, yach????
Jawabnya pake bahasa Indonesia aja dech:
Waktu pake 'wet clothes', airnya 'kan nempel di kulit. Nah, waktu tubuh kamu dikipasi pake 'fan', airnya tadi menguap! Kalornya itu diambil dari tubuh (kulit) kamu, jadi terasa lebih dingin.....