Speaking of using a fan
A lot of people's first reaction is
Just pick it up and blow it
But actually
You may have been using it incorrectly!
Source: giphy
The right way to do it is:
Place the electric fan away from the window
0.5~2.1 meters distance
Then blow into the open window
You can send air to the house
Source: Dr. Lilac
Are you also this
Cognition-disrupting information
Fried to the brittle
I can't wait to give the electric fan at home
Come on with a few ear scrapers
Roared at it: Is this true?
An electric fan blows against an open window
Cooler? It's true!
When surfing the web some time ago
Found a very interesting post
This post uses a small experiment
Bernoulli's law was shown to netizens
The teacher in the post
Holding a long plastic bag and asking
You believe I can take a breath
Just blow this plastic bag all over the place?
Normally, this is not possible
He blew ten times
But it hasn't been able to blow up half of the plastic bag
and sighed that if he blew it again, he would faint
But if Bernoulli's law is used
He can easily blow up the entire plastic bag
This time, he was blowing
Put the mouth and plastic bag opening
Pulled away from it
In one breath, the whole plastic bag was blown up
This is because according to Bernoulli's law
When the air flow rate increases
The corresponding pressure decreases
When he blows
The surrounding air then flows into the area of low pressure
This principle can be applied to electric fans
Blow the fan against an open window
It can make the house cooler
Netizen experiments have found that when the electric fan is 0.5~2.1 meters away from the window, the indoor ventilation effect will be significantly better. The picture is taken from the video of netizen Matthias random stuff
This is because, when the fan is blowing, the air around the fan flows at a faster rate, and according to the Bernoulli effect, the flow rate is high and the pressure is small, and the gas in other parts of the room will move in this direction.
If you can open a window on the other side (even if it's not directly opposite), the cool air from outside will quickly add in, which will quickly cool the whole room.
in everyday life
Some people have already figured out the mystery
There are also netizens who have long been
I touched it inadvertently
The mystery of harmony between man and nature
Some netizens said that it was really useful
Grandmother at home
That's always been the case
There are also netizens
To make the office more comfortable
A fan was placed at the door
Blow to the outside
Another friend said
You can use it to smoke oil
Even a lot of barbecue restaurants
Been using this trick
But see here
You may ask
Since this method is effective
Do you still need to use air conditioning?
Fans don't lower the temperature
Let's talk about the cooling principle of the fan.
The fan seems to just send the wind to you, and the air temperature before and after the fan does not change, so why does blowing a normal fan make people feel cool?
Source: Life Times
In fact, the principle is very simple, and you can simply summarize it with the knowledge you learned in junior high school: evaporation-endothermy-refrigeration.
First of all, the increased gas flow rate can accelerate the evaporation of water (sweat), and the process of water evaporation can effectively remove heat from the surface of the body.
In life, the body temperature of the human body is generally higher than the ambient temperature, so under normal circumstances, our body will release heat to the surroundings, and the air close to the skin will also be "heated".
Source: State Grid Zhejiang Electric Power
If the air flow is poor, the air near the skin is "heated" by the body, the temperature difference with the body decreases, the heat convection will also weaken, and it will be more difficult for the heat on the surface of the body to be transferred. The electric fan can make the air flow, take away the relatively hot air on the surface of the skin, so that the heat convection between the skin and the air can be carried out more smoothly, so we feel cool.
That said, the fan really doesn't lower the air temperature, it just lowers the temperature we feel through the air flow.
Source: Life Times
Take advantage of this feature of the fan, turn on the electric fan while turning on the air conditioner, so that the electric fan can reduce your body temperature by about 2°C. In this way, you can turn up the temperature of the air conditioner a little higher, and you can reduce the electricity bill of the air conditioner.
Finally, I would like to remind everyone
Electric fan in the process of use
Care should also be taken not to use it for a long time
Remember to remind the children at home
Don't put your hands inside
Remember to check the line in time before use
-END-
Edit | Xie Xin
Proofreading | Zheng Fang, Wei Ding, Wang Jianjiao, Huang Ruijiao
Proofreading | Dong Fangjun
Executive Producer | Zheng Yongtao
Source of information | Bilingual news of Popular Science China and China Daily