The average age is in the early teens, and it takes a week to learn this point, even if you have never been exposed to these things before, you can't be so slow, right?

It is even through 'stupid methods' that they can make rote memorization in order to have the 'achievement' they have now......

After a week, Lin Zifan finally determined a little...... The people of the Tang Dynasty, whether male or female, do have more muscles in their brains than their brains!

Otherwise, Teniang can't explain why this is happening!

Even, if it weren't for the pitiful and too young children of these children, Lin Zifan was afraid that he would not be able to help but hang them up and beat them......

It's so!

A week later, Lin Zifan also had to suspend teaching them theoretical knowledge, for no other reason, just because he was afraid that if he continued, he would be angry to death......

It just so happens that at this moment, the weather is getting worse and worse, even in the daytime, it can reach minus five or six degrees or even lower, and at night, it is possible to reach minus ten degrees!

In such weather, if a man lives alone and does not have a thick enough quilt, he is likely to fall asleep and never get up again......

In line with the idea of testing the students' hands-on ability, Lin Zifan decided to suspend the theoretical and cultural courses and teach them to do something...... Ondol!

The clay kang has a long history in northern China, and countless cold winters rely on the clay kang to warm the family......

Fortunately, the principle of the clay kang is not complicated, as long as you know how to do it, or watch the production process twice, you should be able to learn it......

Well...... Probably, right?

Originally, Lin Zifan was very sure of this, but since he became the master of this Lily of the Valley Academy, he was suddenly not so sure......

After all, the learning ability of these bear children is really ...... I can't say.

In fact, there are several ways to do it.

There are two most common kinds, one is to make a fire directly under the kang, simply put, it is to warm the bed board, lie on it and sleep, and it will naturally not be cold......

But there is a problem with this, if you don't grasp the 'heat' well, once the fire is too strong, then the kang will be very hot.

To put it simply, it is similar to teppanyaki, if it is too hot, you have to turn over while sleeping, otherwise you will ...... Confused?

And this kind of earthen kang that makes a fire directly under the kang has another problem, that is...... If you don't get it right, it's easy to get poisoned!

In the previous life of China, people knew that when lighting a fire, they should pay attention to carbon monoxide poisoning, suffocation due to high carbon dioxide concentration, or something, but people in this world don't know what carbon monoxide carbon dioxide is......

Even if you don't use fuels such as coal, carbon monoxide is relatively small, but combustion will consume oxygen and produce carbon dioxide.

Therefore, Lin Zifan chose the second option......

To put it simply, make a hole in the outer wall of the bedroom, build an earthen stove outside the hole, and use the earthen stove to make a fire!

Inside the cave, an earthen kang is built! Under the earthen kang, a layer of clay is pasted first, and then stones or something are used to prop it up.

On top of the stone, a layer of bluestone slabs is laid, and on the bluestone slabs, a layer of relatively thick loess is smeared, and on top of the loess, a layer of square bricks or stone slabs is paved......

Of course, in addition to the kang head and the kang tail, the soil kang must be sealed, and only in this way can it be kept warm for a long time!

For example, if the earthen stove is connected to the kang head, then the wall of the kang tail is also drilled with a hole, and then a chimney is built!

To put it simply, the space under the kang is part of the flue!

Then, when the earth stove makes a fire, due to the suction of the flue and chimney, the flame and the heat flow will naturally pass under the kang, and after a long time, the kang will naturally become hot!

Even with it, the whole house will be a lot warmer.

And because the soil kang has multiple layers, and they are relatively thick, once it heats up, even if the fire is extinguished, the cooling will not be too fast, and there is no need to get up in the middle of the night to make a fire or something, at least in the cold winter, sleep until dawn will not be frozen to death......

It's a hassle to say, but there aren't many steps!

And this time, in addition to the 30 students in the classroom, there are a few more auditors......

Li family sisters!

They also need to learn the art of making clay kang and then spread it out.

As for these students...... cough cough, it's just a 'test product', anyway, Lin Zifan didn't have much hope for them.

Of course, it's best if you can get it, but if you can't, there's no problem.

When Lin Zifan began to 'lecture', the first thing he did was to draw a diagram of the structure of the clay kang on the blackboard and explain many details......

This time, he was very witty and did not talk about the 'theory', that is, he did not talk about why he did it......

Anyway, you just have to remember it for me! Just do it! As for why...... You don't understand it now!

Not to mention, in this way, the efficiency is really good!

Although these bear children have a lot of poor comprehension skills, their memory is still very good, as long as you don't ask them why they are like this, just tell them to memorize them, and they will be able to remember them quickly......

"Remember everything, right?"

Lin Zifan looked at everyone.

"Remember ......" The students also learned to be obedient, and in order not to be scolded or even beaten, they all answered honestly and remembered.

As for the Li sisters, Lin Zifan didn't even bother to ask, they already had a lot of 'engineering' experience, and he believed that a clay kang would not be able to stump them.

Even, even if they don't understand, they will definitely ask themselves later, so there is no need to worry at all, but these students ......

Lin Zifan's eyes rolled, but he didn't ask more.

He just said, "Just remember! Now, I'll give you homework!"

"Hmm...... Civilian students, your family conditions are relatively average, so it is difficult to complete it quickly, so I will give you more time!"

"Within three days, I will work with my parents at home to make a clay kang, and then the teacher will personally go to the acceptance!"

"As for Huo Mei and Yan Wenwen, you ...... I'm going to have to do it today!"

"Now, !! class"

Lin Zifan turned around and left, leaving many students looking at each other.

"Really, this is the end of class?"

"I'll ...... This black-hearted maggot actually got out of school this morning? It's really rare......"

"What is rare, it is clearly the first time!"

"Tsk...... Let's go first, in case he regrets it later...... Tsk, walk!"

The students dispersed in a hurry, and the Li sisters couldn't cry or laugh, but ...... The black-hearted maggot?...... Hey, hey, hey.

As for giving students different time limits for homework, it is not that Lin Zifan treats them differently, but ...... Well...... There is another reason~