The movement of the self-heating rice became louder and louder. Le Zhishi turned away and lip-synced to Jiang Yufan, "Why is there still sound in this??"

Jiang Yufan shook his head crazily and gestured to him to lip-sync, "I don't know either..."

Hu Xuan, who was sitting in the front seat, turned around and raised her hand to make the sign of the cross on her chest with an expression of silence.

But Song Yu seemed to be isolated from the world and showed no reaction. He had even drawn half a mind map on the blackboard. Behind him, the whole class performed a wonderful pantomime while holding back their laughter. The only accompaniment was

The sound of self-heating rice is comparable to the increasingly exciting symphony in the golden hall.

Not only that, this experience is 4D, with hot white mist coming out of Le Zhishi's drawer and the aroma of fish-flavored shredded pork.

Originally, he wanted to eat secretly, but now it's good, the whole class, including Song Yu, who is in charge, all know that he is cooking.

Le Zhishi gave up completely. He already had a scene in his mind where he was scolded and ordered out of the classroom, and then squatted in the corridor and ate sadly.

He feels that he is now a very experienced person and can anonymously answer the question "What is the experience of social death" on Zhihu in a lively and vivid manner.

Finally, ten long minutes passed. Song Yu turned around expressionlessly and placed the half-used piece of chalk on the desk. "This is what I want to say next."

The sound of the self-heating rice began to sound like a deflated balloon, and the sound became increasingly wilting, just like Le Zhishi's head hanging down on the table.

"The first part is to find your weakest link. You all know the barrel effect." As Song Yu continued, he got off the podium as expected.

Rows of students under the podium hurriedly put away their mobile phones. The student at the front turned to look at Le Zhishi with the mentality of watching a show.

Rumor has it that the person who bullied his younger brother came to teach the class, so he caught his younger brother stealing food in class. If he didn't teach him a lesson, it would be unjustifiable no matter how hard he thought about it.

"Systematically sorting out wrong questions is an effective method. It's not scary to make mistakes. Everyone makes mistakes. What's scary is that many mistakes will be repeated over and over again, eventually leading to loss of points. So what you should do is to reduce the frequency of the same mistake."

As he spoke, he had already walked to Le Zhishi's side, his slender hands seemingly unintentionally propped up on his desk.

He spoke at a steady pace and with smooth logic. He talked about topics ranging from sorting out wrong questions to techniques for scoring multiple-choice questions in mathematics, such as graphic combination methods, substitution methods, etc. As an ostrich, Keke Zhishi had nothing but the sound of his own heartbeat.

, can't hear anything.

As if he was deliberately torturing him, Song Yu stood beside him and said, not going anywhere.

"...This is the multiple-choice question part. Now you can use the questions at hand to practice the multiple-choice question skills just mentioned. It will take ten minutes." After saying that, Song Yu finally lowered his head and looked at Le Zhi, who had been pretending to be dead.

, he tapped his knuckles lightly on the table.

Only then did Le Zhi raise his head pitifully, with an expression as if he really knew he was wrong, and honestly took out the self-heating rice box hidden in the drawer.

Song Yu raised his eyebrows and asked in a low voice, "Does it smell good?"

Hearing this sentence, several students around him couldn't hold back their laughter.

"It's okay." Le Zhishi replied very sincerely, and then added in a low voice, "It smells a bit fragrant."

Jiang Yufan is a loyal person. When he saw that Song Yu was in trouble, he immediately explained to him, "Senior, I bought this. If you buy it wrong, blame me. I can write a review."

Seeing that he wanted to take responsibility, Le Zhishi immediately said, "No, I want to eat it myself."

Zhang Chen didn't mind watching the excitement, "Senior, I can prove that it was eaten by Le Zhishi. They had been secretly discussing it for a long time, just wanting to eat self-heating rice during evening self-study."

Jiang Yufan was very angry, "Are you qualified to say that? It's like you haven't eaten takeout during your self-study in the evening. And he didn't plan to eat in the classroom."

The two started arguing. Song Yu's eyes swept across the laughing students. Everyone seemed to be looking forward to his punishment. Finally, he spoke expressionlessly.

"I would like to take this opportunity to tell you about the principle of self-heating rice."

Zhang Chen's face was full of disbelief. This was completely different from the direction he thought he would take to register and punish him for standing and suing for three consecutive years.

Ignoring the whispers of the students around him, Song Yu picked up the lunch box on the table and said, "Look here."

"There is a heating pack at the bottom of the self-heating rice box, which contains chemical agents such as quicklime, sodium carbonate, and aluminum-magnesium mixture. Quicklime is calcium oxide. It reacts with water to form calcium hydroxide and releases a large amount of heat. Carbonic acid

Sodium often plays an auxiliary role in it, and aluminum magnesium powder can also release heat through oxidation reaction. So when we inject water, the heating pack will work and automatically heat the food."

He lowered his head, met Le Zhishi's surprised eyes, and continued: "However, this kind of self-heating instant food may explode, and the food is not fresh enough. It is not recommended for everyone to eat it regularly."

After saying that, Song Yu put down his lunch box and pointed back to the blackboard, "I have written several related reaction equations in the lower right corner of the blackboard. Interested students can take a look."

Le Zhi looked at the equation on the blackboard. It turned out that he already knew what happened at that time and wrote it down calmly.

At first, everyone just thought it was funny and wanted to see the excitement. Unexpectedly, the social death incident suddenly changed the chemistry class, and they were still a little confused. The amazing thing is that they had learned some of the reactions in it, but they had never connected it to life, so

When you compare it, it feels magical.

"Based on the example just now," Song Yu leaned against Le Zhishi's table, "Everyone should never forget that when calcium oxide meets water, it is an exothermic reaction."

Everyone laughed in unison, but Zhang Chen was obviously unwilling to give in. He raised his hand with a mean expression on his face, "Senior, why is there a sound? It's so funny."

This is obviously to bring everyone's attention back to the time when the self-heating rice was sizzling.

Song Yu leaned against the table and did not answer directly, but looked at the other students, "You should have done chemical experiments. Can anyone tell me which chemical experiments you have done have special sounds?"

A girl whispered, "Sodium and water..."

Song Yu nodded to her affirmatively, "This example is very classic. Many chemical reactions will make sounds." He specifically glanced at Zhang Chen who just asked the question deliberately, "It's nothing to make a fuss about."

Zhang Chen's face quickly lost its composure, and he could clearly feel the hint of ridicule in the other party's cold tone.

"Except for the reaction itself, a large amount of water vapor will be produced during the exothermic process, and a sound will be emitted during the collision. This process includes many reactions similar to galvanic batteries, which you have not learned so far."

Song Yu lowered his head and glanced at him, "I believe...if classmate Le Zhishi knew the principle behind this from the beginning, he would not choose to heat self-heating rice in a quiet environment."

Classmate Le Zhishi.

This title sounded strange to Le Zhi, but somehow it evoked a sense of joy.

Although Song Yu still had a cold expression, he did not mean to accuse him. Every sentence was clearly intended to popularize chemical knowledge, but everyone could hear the underlying meaning of exculpation.

Le Zhi thought that now the bottom of his anonymous answer could be updated in real time with the sentence "I'm alive again!" No, he could even cancel his anonymity.

While he was in a daze, a broad palm fell on his head and rubbed his fluffy and soft hair. It was very brief and very light. He didn't react. He only felt that the hand left his head, but he left a sentence

.

"If you don't eat it, you'll be cold."

This head-butting attack happened suddenly, and the students around were a little surprised.

The rumors that the brothers had a bad relationship were completely shattered by Song Yu's extremely rare close contact.

Le Zhi didn't even raise his head, "I'm going out to eat."

After he finished speaking, he took the lunch box and walked out, feeling a bit like he was in the same boat.

The bathroom was on the right side of the stairs, next to the restroom. Seeing that no one was there, Le Zhi slipped in. The convenience food tasted very ordinary, the rice was hard, and the vegetables were a bit too salty.

He was in a daze while chewing. After swallowing, he raised his hand in a daze, touched the top of his head, lowered his head and took another big mouthful.

He was so hungry that he didn't even feel hungry, and what happened just now happened again. Le Zhi couldn't eat much, and he was thinking about what Jiang Yufan said about wanting to taste it, so he didn't leave even after eating. But the little Jiang Yufan has experienced too much.

I can't remember anything. I waited for five minutes and it didn't come.

Song Yu was still in the class, and Le Zhishi didn't want to ink for too long, so he cleaned up and returned to the classroom. When he arrived at the door, Song Yu was standing on the podium talking about the English review plan. He stood at the door and softly shouted a report, but did not go in directly.

Hearing the voice, Song Yu nodded to him and continued talking as if nothing had happened.

Le Zhi returned to his seat quietly and listened to the lecture with other students. After the whole class, Song Yu, who did not bring any materials, only spent ten minutes to sort out the context of the mind map, and then led everyone through it with a clear mind

Once again, the level of ease even exceeded that of many teachers.

"Time is limited, let's just talk about this." Song Yu stood sideways, lowered his head and looked at his watch, he was about to start the first period of evening self-study.

"Happy to know the time."

When he heard his name being called, Le Zhishi was stunned for a moment and quickly looked up at his brother.

Song Yu tapped his chin in the direction of the blackboard, "Wipe the blackboard."

Le Zhishi immediately nodded obediently, "Yeah." He stood up.

Growing up, Le Zhishi's biggest fear was that Song Yu would ignore him, especially after he did something wrong. But if Song Yu taught him a lesson or gave him something like punishment, it meant that he was not angry.

.

Song Yu cannot speak when he is really angry.

They all know each other well enough.

"Don't erase it," the girl who took notes raised her head. She didn't pay much attention to the explanation before, but now she was rushing to copy the writing on the blackboard. "I haven't finished copying it yet." Others also shouted, and they were in a dilemma.

Song Yu glanced lightly and said, "Since the mobile phones you brought can chat, they should also be able to take photos."

Everyone was choked by this sentence, especially those who were chatting and laughing in the group just now.

The bell rang and Song Yu left the classroom. Le Zhishi wiped the blackboard as he asked. Jiang Yufan showed loyalty and took another blackboard eraser to accompany him, "Is that meal delicious?"

"It's okay." Le Zhishi looked at him, "I waited for you for five minutes, but you didn't go."

"You've been waiting for me for a long time. Why did it take so long? I forgot." Jiang Yufan rolled up his sleeves and said, "That idiot Zhang Chen even criticized you, saying you were too embarrassed to come back. He was so angry.

If I can’t catch myself, I’ll vent my anger on others.”

Le Zhishi waved his arms and worked hard to wipe the blackboard, and didn't really care who said what when he was away. "He only had a habit of talking for a day or two. If the person I like likes someone else, I will definitely not be happy either."

"The hand holding the eraser suddenly stopped, and Le Zhishi's eyes stayed on the lines of equations in the corner.

This was the last unfinished task in the clearing task assigned to him by Song Yu.

"Do you have your phone with you?" He turned to look at Jiang Yufan who was dusting off the phone.

"Here, what's wrong?" Jiang Yufan took it out and handed it to him, "You just remembered to take a picture now, but it's gone."

Le Zhishi didn't say anything and used his mobile phone to take a photo of the lines of equations in the lower right corner.
Chapter completed!