In the afternoon, when Li Zicheng went to the school with a wooden box, Sun Mengjie, Chen Qiudie, and Mu Sirong were all accompanied, and the students saw Li Zicheng carrying a strange box, and asked Sun Mengjie about them, but the reply they got was all no comment, and even Sun Lin asked her sister about the things in the wooden box, and she also touched the nail.

In fact, they didn't know what was in the box.

The first two classes were Chinese and mathematics as usual, and in the third science class, Li Zicheng took out the box, put it on the podium, and said: "I know everyone is curious, don't worry, you will know the result if you are very open!" ”

The students immediately discussed:

"What exactly? It can't be a dessert, right? It's like a rice shrine! ”

"If you want to be beautiful, how can an adult bring dessert to the school?"

"Don't make any noise, maybe you can bring desserts, and there will be results soon!"

……

Li Zicheng directly ignored the students' discussions, and continued: "I once said in the school that there are a large number of bacteria in our world, and today I will let you see if bacteria are real!" ”

"Bacteria?" The students exchanged their heads and ears, and many of them had long forgotten about the bacteria, but Sun Mengjie remembered, "Microscope, is it a microscope in the wooden box?" ”

"A microscope, indeed." Li Zicheng opened the wooden box, carefully took out the microscope, put it on the lectern in front, and called two students to assist in installation and commissioning.

He took out a small piece of chicken from a small square wooden box, which had been cleaned, scraped so thinly as transparent as the white paper on the window, moistened with water, and spread flat on the stage.

Li Zicheng first aimed his right eye at the eyepiece, looked at it carefully, and adjusted the stage with his hand until the bacteria clearly appeared on the stage, and then said: "You guys line up, come up and watch one by one, be careful not to touch the microscope, and then describe the bacteria you see in words!" ”

Chen Qiudie grabbed the first position, she followed Li Zicheng's example, closed her left eye, focused all her energy on her right eye, took a deep breath, and then looked at her right eye against the eyepiece.

"Wow, that's amazing, these little bugs, they'...... They greeted with tentacles, hey, this greedy little thing, under their noses, is still greedy, and their bellies are swollen like big drums......"

Chen Qiudie has not yet enjoyed it, and has already been bombarded by other students, and all the female warblers and warblers have been chattering for a while in their own languages, and they still refuse to stop.

Li Zicheng waited for all the students to see it once, walked over in person, and looked at the eyepiece again, all kinds of bacteria were basically clear, but the chicken intestines were blurry, turbid, and the effect was extremely unsatisfactory, so he took off the chicken intestines and replaced them with a slice of the skin of an onion.

The slices were extremely thin, almost transparent, and he washed them with a high degree of liquor before placing them on the stage.

From the eyepiece, the long cells, like a wooden floor, are arranged extremely densely, and even a black spot will appear in each cell, which is not bad, and the effect is not bad!

Li Zicheng asked the students to come forward to watch one by one, and also described the pictures they saw in their own words.

The girls were chattering like birds again, and after Sun Lin saw it, he asked softly: "My lord, the onion epidermal cells are like square bricks, but in each cell, there is a small black spot, and the subordinates noticed that there are almost every cell, and it cannot be the dust stained on the glass plate." ”

"Sun Lin observed really carefully," Li Zicheng praised again, turned around and asked the students, "Have you noticed this black spot?" ”

Li Dan pondered for a while, and said softly: "There seems to be a small black dot, I just looked at the neatly arranged cells, and I can't remember it clearly......

Li Zicheng summed up in a timely manner: "Cell, is the basic structure of all living organisms, including animals, plants, and us humans, in general, bacteria is a cell, but the cell itself is not an inseparable solid body, but composed of a smaller structure, just now Sun Lin saw the small black dot, is the most core component of the cell, called the nucleus, and the rest of the cell, we can call it cytoplasm in general." ”

Seeing that all the students were staring at each other, Li Zicheng knew that this kind of microscopic world that meat could not see, and he was relatively unfamiliar with the students, so he further made an analogy: "If the cell is regarded as an egg, the nucleus is equivalent to the egg yolk, and the cytoplasm is equivalent to the egg white filled in the egg shell." ”

The students were originally ignorant, but Li Zicheng's analogy, they somewhat understood, Mu Sirong tilted her head and said, "My lord, is the outside of the cell also like an egg, wrapped in a layer of eggshell, or the film inside the eggshell?" ”

"You're right," Li Zicheng also extended a thumbs up to her, being able to ask questions, to some extent more important than solving problems, at least giving a research direction, "On the periphery of the cell, there is indeed a membrane that protects itself, wrapping the entire cell, and this membrane is called the cell membrane." ”

Mu Sirong was praised by Li Zicheng, her little face was red with shame, but her heart was warm.

Sun Mengjie had been thinking about it, and suddenly asked, "Didn't Mr. say that bacteria are everywhere in our lives?" So why don't we see bacteria on the skin of onions? Could it be that bacteria are also afraid of the smell of onions? ”

"That's exactly what I'm going to say," his big and small wives have scientific potential, Li Zicheng is very happy, at least they are immersed in the science education of this class, "Maybe some bacteria will be afraid of the kind of gas emitted by onions, so when people store grains, they often mix some garlic or onions to prolong the shelf life, but there are always some bacteria that can adapt to the smell of onions, just like some people like to eat garlic and onions." ”

All the students looked sideways and listened carefully to every word of Li Zicheng.

"Actually, there are many bacteria on the skin of onions, but have you noticed that I have washed the skin of the onion in liquor before putting it on the stage?"

"Liquor?"

The students then remembered that before Li Zicheng put the chicken farm on the stage, it was moistened with water, and when the onion was put on, it was moistened in liquor, just now they focused on observing the bacteria, and they didn't care too much about the smell of liquor.

"Yes, the liquor has the effect of sterilization and disinfection, the onion is washed in the liquor first, and the bacteria on the surface are killed, but there are still many bacteria in the air," Li Zicheng circled his fingers, "Soon after, the bacteria in the air will still enter the onion skin, you can take a look, what is the difference between the current onion skin and just now?" ”

As Li Zicheng said, on the skin of the onion, there were indeed small insects that could crawl, although they were not as dense as those on the chicken intestines, but there were already a lot of them.

They suddenly sighed, the bacteria are so small, but they are so obedient to their husband, could they have raised them by their husband?

One of the students asked, "Sir, since liquor can be disinfected and sterilized, don't men kill many bacteria when they drink alcohol on weekdays?" No wonder men rarely get sick......"

Everyone burst into laughter, and the student turned red-faced, not knowing what he was doing wrong.

Li Zicheng encouraged the students to ask questions, and when everyone's voices were quieter, he said: "In this student's speech, he raised two questions, one is the relationship between liquor and bacteria, and the other is drinking and health. ”

“……”

"Liquor can indeed sterilize, but it must be a high degree of liquor, the alcohol content must at least reach the level of distilled spirits, if it is ordinary soju, self-brewing, it is not obvious in sterilization, so drinking alcohol can not strengthen the body, nor can it go to disease, but alcohol can accelerate the flow of blood, has the effect of keeping out the cold, people in the north, in the cold winter season, wine does not leave the mouth, this is the reason."

After all, these common senses in life always contain rich and varied scientific knowledge, which cannot be completely solved in the time of one class, and these are not the teaching content of this class, and Mr. did not ask them to memorize them.

Li Zicheng continued: "The second question, men are strong and less sick, not because of drinking, in fact, if you drink too much, it will have a certain negative impact on the heart, stomach, etc., and even affect your health. ”

Sun Mengjie and Chen Qiudie suddenly flew over a white eye, and said in their hearts: Then why do you still drink...... However, it seems that Mr. (adult) is not a good drinker, and excessive drinking is very rare.

The students also have their own hearts, at least in the future, they will tell their men that if they want to be healthy, they should drink less, but Li Dan set his eyes on Sun Lin, and saw that Sun Lin was contemplative, and did not look at himself, his warm gaze turned into a sword, and he secretly stomped his little feet.

"Men are strong, mainly because of exercise," Li Zicheng suddenly stopped talking, let the students talk for a while, and said: "Life lies in exercise, if you exercise regularly, your physique will be improved, and the number of illnesses will be less." ”

Chen Qiudie sighed: "No wonder adults like to exercise in the morning......"

Sun Mengjie's face suddenly turned red, obviously thinking about it, she immediately thought of what her husband had said to her, "just run in bed", and even after dawn, her husband had to "exercise" on their sisters......

Fortunately, all the students were thinking about Li Zicheng's words, and did not notice the changes on Sun Mengjie's face, she rubbed her face with her fingers, wanting to disperse the shameful heat as soon as possible, Li Zicheng's next words, she didn't listen to a word.

I don't know that it took a long time for Sun Mengjie to return to normal, in order to cover up her gaffe just now, she took advantage of her husband's pause, and suddenly asked: "Since Mr. said that bacteria are everywhere, can the bacteria on our hands be seen under the microscope?" ”