Why is it cool when people fan on a hot day?

Because a fan can make the air flow, it produces wind, and when there is wind, it will be cool

In the summer, everyone has to fan a fan, as well as blow an electric fan. Why is it cool to fan on the body? Some people say that it is because the fan cools the air.

Is this true? No, completely wrong. If you don't believe it, you can use a thermometer to blow it in front of an electric fan!

You will see that the mercury column of the thermometer is always the same. It can be seen that fans or electric fans are not able to cool the air. Go ahead and do another experiment:

You sprinkle some water at the same temperature as the air on the mercury ball of the thermometer and then blow it on an electric fan. Now you can see that the column of mercury is starting to fall. Why is that?

Since the mercury ball on the thermometer has to consume heat when it evaporates. In this way, the temperature of the mercury ball will decrease, so the mercury column of the thermometer will go down. Our body is also constantly emitting heat and water, and when this water evaporates, it may take away some of the heat from the body, and we will feel cool.

On the one hand, the fan is to drive away the hot air next to the body, so that the surrounding air can flow over quickly to replenish; On the other hand, the evaporation of the body is accelerated, and because the evaporation is fast, the heat lost by our body will also increase, and people will feel cooler. On wet and windless days, evaporation proceeds quite slowly, and sometimes stops, so that we feel very stuffy; On dry and windy days, evaporation is fast, so we feel very refreshed and comfortable.

Because the fan is good-looking, the mood is good, the more the fan is cooler, the air is good, the mood is good, of course, it is cool, and the heart is calm and naturally cool

Because it's fanned. It's cool.

Because the electric fan accelerates the flow of air, and the flow of air can accelerate the evaporation of sweat on people's bodies, and the evaporation of sweat can take away heat, so people will feel cool.

At the same temperature, when the density of water molecules in the air (commonly referred to as humidity) is relatively small, it means that the number of water molecules jumping out of the air into the liquid water is much smaller than the number of water molecules escaping from the liquid water, and the lower the density of water molecules in the air at the banquet ridge, the greater the difference in the number.

The effect of the wind blown by the fan is to blow away the water molecules in the air on the surface of the liquid water and replace it with drier air. In this way, evaporation can continue at a relatively high rate, and the person will feel relatively cool.

When the fan is fanned, the air flow speed in the area being fanned is accelerated, and the air pressure is small, which causes the air pressure difference, which creates wind, and the fast flowing wind will speed up the evaporation of the liquid on the surface of the body, and the evaporation will absorb the heat from the body, so it will make the human body feel cool.

The types of fans include feather fans, pu fans, pheasant fans, group fans, folding fans, silk palace fans, mud gold fans, black paper fans, sandalwood fans, etc.

The fan was first called a fan and has a history of more than 2,000 years in China. It was not originally used to cool off, but as a ritual tool. Gradually, the fan transformed from a symbol of status and power to daily necessities and handicrafts such as coolness, entertainment, and appreciation.

The styles of fans mainly include wavy type, monk head type, collection style, pointed head type, Japanese style, thin tip type, fish tail type, etc. Content.

You must have had such an experience: in the hot summer, you rushed to the house, turned on the electric fan, and suddenly felt comfortable and cool. In fact, the wind blown by an electric fan is not a cool breeze, so why do you feel cool?

It turns out that the wind blown out by the electric fan is just hot air with the same temperature as the house, and if you have sweat on your body, the Zhonghong laughing wind will quickly evaporate the sweat and leave **. When the sweat evaporates, it takes away the heat of the acre, and in this way, you will feel cool!

01 Because the electric fan accelerates the flow of air, and the flow of air can accelerate the evaporation of sweat on a person's body. The evaporation of sweat can take away the heat, so the person will feel cool.

Use an electric fan to blow the thermometer, and the thermometer indicates that the temperature has not dropped. This means that electric fans cannot cool the air.

So, why does blowing a fan feel cool? There is such an experience in daily life: after a period of time, the water on the clothes will turn into water vapor and run away, and the clothes will become dry.

The process by which a substance changes from a liquid state to a gaseous state, which occurs only on the surface of the liquid, is known as evaporation. If you wrap a damp cloth around the alcohol ball of the thermometer and then blow the thermometer with an electric fan, thereby accelerating the evaporation of water on the damp cloth, you will find that the alcohol column of the thermometer drops, indicating that the temperature of the water on the damp cloth has decreased.

This occurs because water evaporates and consumes energy to absorb heat from surrounding objects. Rubbing a little alcohol or water on it will feel cool, which is due to the fact that alcohol or water evaporates from the human body and lowers the temperature. When the weather is hot and humid in summer, the sweat on the body is difficult to evaporate, after the electric fan is turned on, the flow of the surrounding air is accelerated, on the one hand, it drives away the hot air that surrounds the surface, on the other hand, it also accelerates the evaporation of sweat, taking away more heat from the body, so people feel cool when blowing the fan.

When the fan is fanned, it will touch the wind, mainly to increase the air flow, so that the air around the human body is at a lower temperature, accelerate the heat transfer speed between the human body and the air, and it is conducive to the evaporation of human sweat, and the evaporation of sweat is also conducive to cooling. So a fan will feel cool.

Fan Fan will have wind and make use of the physical principle of air movement.

The biggest difference between the wind of an electric fan and the natural wind is:

The natural blue wind is advection, like a river.

The wind of the electric fan is like the water behind the propeller, it is rolled, and it is a horizontal whirlpool.