Li Su saw Li Ning'er's appearance and secretly praised: "What a cleverness! ”

Li Ning'er handed Li Shimin a bottle of Coke, and then handed the other two bottles in her hand to the eldest grandson Wuji and Fang Xuanling. Pen ~ fun ~ pavilion www.biquge.info she reminded: "Uncle Emperor, Uncle Eldest Sun, Grandpa Fang, this is called Coke, drink it slowly, there is gas in it." Then, tell them how to unscrew the Coke.

Li Shimin felt very cold, so he took a small sip, and then, the speed of drinking began to speed up, and after a while, half of the bottle went down. Suddenly, he put down the Coke, covered his nose with his hands, and his face changed drastically.

Ma Xuanliang, the chief of the guard who followed them, was shocked, and his first feeling was that the emperor was poisoned. He was just about to step forward to escort him, when he suddenly remembered that it was Li Ning'er who handed the emperor a drink, and she would never harm the emperor. So, he continued to observe.

After a while, Li Shimin came to his senses. He smiled: "This cola is very angry, and the momentum is really not small." ”

The eldest grandson Wuji and Fang Xuanling accepted Li Shimin's lesson and drank it in small sips.

The young princes, the royal ladies looked at Li Shimin with blank eyes, and their eyes focused on the Coke bottle in his hand.

Li Shimin had no choice but to hand the bottle to Princess Dongyang beside him, and said, "Cheng Qian, Su'er, take out some more, let your younger brothers and sisters eat enough." ”

Li Su said: "Father, you can't eat too much of this cold drink at a time, it will hurt your body." ”

Before he could finish speaking, Li Zhi and the other young children shouted: "Sixth brother, we are not afraid!" ”

Li Su said: "Okay, when you leave, I'll take it away for you?" ”

"Okay!" The children cheered.

Next, it's time for the official class.

Li Su walked up to the podium, picked up a piece of chalk and wrote on the blackboard: atmosphere and atmospheric pressure.

Then he turned around and said, "...... today."

"Wait a minute." Kong Yingda said.

Li Su asked respectfully, "Master, what do you command?" ”

Kong Yingda asked, "What is on your wall, and what are you writing in?" ”

"It's called a blackboard." Li Su explained the principle of the blackboard and demonstrated the role of the blackboard.

Kong Yingda said: "Your Majesty, this is a powerful tool for teaching, and the emperor is invited to vigorously promote it." ”

Li Shimin said solemnly: "Prince, Li Su, you have such teaching tools, why didn't you report it earlier?" ”

Li Chengqian said: "Father, son, and sixth brother are conducting experiments in the industrial school, and they are preparing to report to you after the test is completed." ”

"Well, that's like words. Let's move on. Li Shimin said.

Li Su said: "Today's physics class is about the atmosphere, which is usually called air.

The atmosphere exists around us, it can't be seen or touched, but it's real. What we breathe every day is the air, and when the wind blows, the air is flowing. ”

Li Su did not talk about the quality of the air and other incomprehensible issues, but only talked about the use of air.

He first talked about the use of wind energy, such as windmills to draw water, transmit wolf smoke signals, and so on. Next, he talks about atmospheric pressure.

"Since the atmosphere is real, it has an impact on the surrounding things, such as atmospheric pressure. In order to visually describe the existence of atmospheric pressure, below, I will illustrate it with an experiment. ”

Li Dan and Du He hurriedly put the experimental tools on his podium.

Li Su picked up a transparent glass, filled it with water, picked up a thick piece of paper, and pressed it against the mouth of the cup. Then turn it upside down and slowly let go of your hand.

A miracle happened, the piece of paper didn't fall and held the water in the cup!

There was an uproar in the audience, and everyone, including the students of the technical school, was stunned.

In order to emphasize the dramatic effect, Li Su deliberately said: "Li Zhi, you come to do me a favor." ”

Li Zhi looked at Kong Yingda and asked for his opinion. Kong Yingda nodded, and Li Zhi stepped onto the podium.

Li Su said: "Ninth brother, you bring that copper basin over. ”

Li Zhi picked up the copper basin from the ground and placed it on the table.

Li Su pointed the glass at the copper basin and motioned for Li Zhi to remove the paper from the mouth of the cup.

With a "bang", the water in the cup fell into the copper basin.

"Thank you, Brother Nine." Li Su said.

When Li Zhi returned to his seat, Li Su said: "This is the atmospheric pressure, the reason why everyone usually can't feel its existence is because the atmosphere surrounds us from all directions, and the pressure is balanced."

The air in this cup is occupied by water, and the pressure of the atmosphere is pressed on the piece of paper, holding the water in the cup. ”

Kong Yingda nodded again and again.

Li Su continued: "What is the use of atmospheric pressure? Let's do another experiment. ”

Li Dan and Du He placed two large glass beakers on the table, one of which had a lot of red solution in it.

Li Su picked up a transparent plastic tube, filled the tube with liquid, and then inserted one end into the red liquid, and the other end into another beaker, and the audience saw that the red liquid, over the height above the glass beaker, flowed into the other beaker continuously, until the red liquid on both sides was flat.

Li Su asked, "Do you know what's going on?" ”

Li Ke and Li Tai both seemed to have realized something, but they were not sure. Several students from the technical school raised their hands and asked to speak.

Li Su originally wanted the most clever Li Ning'er to answer, but suddenly he had an idea and said, "Tian Zhen, you can answer." ”

Tian Zhen stood up and said in a crisp voice: "The red liquid in the beaker is under the pressure of the atmosphere, and when the tube filled with liquid is inserted into the red liquid, the atmosphere will press the red liquid into the tube, and the liquid will be pressed out from the other side of the tube.

When the liquid on both sides is equal, the atmospheric pressure on both sides is the same, and the liquid stops flowing. That's it. ”

"Very good, correct answer, please take a seat." Li Su said.

Then, he specially introduced: "This classmate Tian Zhen is the daughter of an embroidery merchant in Chang'an West City, she is very smart and studies very hard, and I praise her here." ”

Tian Zhen is beautiful in appearance, has decent manners, and is wearing a school uniform, so she can't see her identity. Just when people were speculating about her identity, Li Su's words made them feel a little surprised, and they said in their hearts: "It turns out that the daughter of a businessman can also be so good." ”

Li Shimin's heart was also a little touched. After the fact that businessmen took the lead in buying treasury bonds, his mind has changed slightly about businessmen. Tian Zhen's performance gave him a better understanding of businessmen.

Li Su continued to lecture, and he said: "This experiment just now is called siphoning. What does a siphon do? Let's give you an example. He turned around, drew a simple pattern on the blackboard, pointed to it, and said:

"This is the Yellow River, and its riverbed is very high, and there are many areas around it that are below the river level......"

At this time, Li Ke interjected and said, "Sixth brother, I understand. The water from the Yellow River can be used for irrigation, but the embankments cannot be opened and will cause flooding. This siphon principle can be used for water diversion irrigation. ”

Li Ke was indeed smart, and immediately understood what Li Ke meant.

Li Su praised: "What the third brother said is very right. ”

Li Ke was praised in public, very happy, and a flower smiled on his face.

At this time, Li Tai, the king of Wei, was reluctant.