Live broadcast: Ancient people accompany me to make up lessons

The sixth lucky viewer, Wang Xiaotong, was born in the Northern Zhou Dynasty and has lived to this day. He has considerable experience in arithmetic. While he is still alive, his "Ji Gu Suan Jing" has become the arithmetic textbook of the Imperial College.

He likes mathematics, but he still doesn’t understand the calculation methods in chemistry, so he imitated the anchor’s teaching of chemical elements and asked the anchor how to draw the equal sign in the long series of chemical formulas for the VB2 battery electrode reaction. .

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["Well, let's start with the valence formula: monovalent potassium, sodium, chloride, silver; divalent calcium, barium, magnesium and zinc; trivalent aluminum, tetrasilicon, pentavalent phosphorus; divalent, trivalent iron, divalent carbon; divalent, divalent Sulfur is complete; divalent copper and mercury are the most common; zero valence of elemental substances must be recorded. Negative monohydroxide nitrate; negative dicarbonic acid sulfate; positive monovalent ammonium; negative trivalent phosphate. Gold is positive and non-negative elemental Zero; hydrogen one oxygen two should be remembered; the sum of the positive and negative prices is zero; many elements have variable prices; the prices are different under different conditions.

When making chemical formulas, you must keep in mind the law of conservation of mass, and grasp five constants, two certain changes, and one possible change:

The total mass of reactants and products remains unchanged; the types of elements remain unchanged; the types, numbers, and masses of atoms remain unchanged; the types of substances must change; the types of molecules constituting substances must change; and the total number of molecules may change.

Then according to the law of conservation of mass..."]

Seeing the anchor's confident and calm manner, writing, drawing, and speaking at the same time, many people under the canopy felt swollen.

Please, anchor, why don’t you say something else, maybe stars, this is one price, two prices, exchange, reaction, I don’t understand it at all, why is that element written there and pronounced like that, what is positive and negative? , no connection at all, okay?

Looking at his descendants with pale faces, Wang Xiaotong gave them a roll of his eyes: "Isn't this very clear? It's not difficult to calculate. It's rare to understand their reactions and make a suitable exchange."

He firmly remembered the five principles mentioned by the anchor. When he watched the anchor talk about the simple chemical formula of rusting iron based on these five principles, he felt that it was nothing special. There are so many things that remain unchanged. It is not difficult to deduce based on these unchanged things.

Children and grandchildren of the Wang family: Dad, Grandpa, this is really difficult!

"Why is it so difficult? The host even reported the periodic table of elements and the valence formula. He explained it so clearly. You still don't understand it?" This math is really simple, isn't it?

Wang Xiaotong doesn't care about a few white descendants. Now he feels that his book can add some content. No wonder the anchor said before that the principle of equivalent exchange in alchemy cannot be practiced out of thin air without gold. Look at these formulas, It is indeed an exchange of equal value and cannot be changed out of thin air.

But whether existing elements can be combined and exchanged at will to turn into something new, Wang Xiaotong thinks it is feasible.

The old man is now full of confidence. Mathematics is too difficult. There is nothing he can do if his descendants don't have this talent. But chemistry at least does not require as much talent as mathematics. If you can learn it well, let alone making a molecule stable, it will not be easy to produce. Rusty iron, this has not yet gone down in history.

By the way, it must be written down. If Sun Simiao hadn't recorded it in his own book, who in the future would know so clearly!

When he thought about how much he still had to do, he felt like he could live another life.

Zhou Sheng is just an ordinary person. He doesn't understand much of what follows, but after following the anchor and answering the first question correctly, he is very curious. What is the Tyndall effect?

["Well... Tyndall effect, let me do an experiment for you." Xiaoxiao happened to be tired from reading chemistry questions, rummaged in the pen holder and drawer, and took out a laser pointer.

I opened it and looked at it. It still had electricity, so I took it to the kitchen.

He took out a transparent glass, poured water into it, and placed a pack of heavy-colored seaweed behind the water glass. Xiao Xiao reminded: "Now we turn on the lights, pay attention to the light."

When the laser pointer is turned on, the transparent water glass only has red light spots on the left and right, proving that light has passed through it, leaving a little red on the black seaweed. 】

Someone reflected that something was wrong: "When the sun shines down, the light is clearly visible. Why can't we see this red light?"

[Xiao Xiao picked up the salt shaker next to him, scooped a spoonful of salt into the water, and stirred it with chopsticks. I continued to use the light pen to illuminate it, but there was still no change.

She poured out the salt water and took another glass of water. This time she poured a little milk into it, stirred it evenly with her chopsticks, and continued to turn on the laser pointer. 】

Ancient people under the sky: So, do you just pour the brine made of snow-white salt like this? It’s good to drink it!

I really wanted to scold her for being wasteful, but considering that she had no worries about food and drink, they could only accept it with an awkward sigh.

[Unlike the transparent water before, this time a blurry, straight, reddish beam of light can be seen in the pale white liquid.

When the perspective is moved up from the parallel front of the cup, the red light in the water becomes clearer, but in the air between the water cup and the seaweed, the light path is completely invisible. 】

Everyone who watched her complete the process widened their eyes and were surprised by the results of the three groups of controlled experiments.

"It's really different! I saw a red light!"

"Why can't plain water or salt water work? Just add some milk?"

"Is it because the milk has been added to make it more colorful, so you can see the light?"

"The light is originally red, why can't it be seen in the water?"

[Xiao Xiao turned off the laser pointer, poured out the water, and explained: “When a beam of light passes through the colloid, a bright “pathway” can be observed in the colloid from the direction of the incident light. This phenomenon is called Tyndall. Phenomenon. Our little experiment just now is a light scattering experiment.

The milk drops into the water and forms a colloid, so the light path is visible. Salt dissolves in water, forming a solution, so the light path cannot be seen.

溶液中粒子大小（不超过1nm）＜胶体中粒子大小（40nm-90nm）＜可见光波长(400nm—750nm)。

When visible light passes through colloids, there will be significant scattering. For solutions, although the molecules and ions are smaller, the intensity of the scattered light is significantly weakened as the volume of the scattering particles decreases, so the salt water in the solution cannot see the light. ”]

Many people understand. No wonder you can sometimes see light beams when you go to the woods. That is because the air in the woods obviously contains various colloids with relatively large particles.

Many people are also very interested and want to do an experiment.

"Qingque, you don't have the anchor's laser pointer." Li Chengqian tried to dispel his brother's interest.

Li Tai, who was fascinated by the experiment: "We have glass cups. The sun is strong today, so fill it with water and go outside. Use a wooden board to leave a small hole. Wouldn't there be natural light?"

If there are no conditions, just create the conditions yourself. What kind of light can be as strong as the sunlight that radiates the entire solar system?

"We will do this after our father is gone." Li Chengqian thought for a moment, and he was actually very curious. He quickly accepted this method and taught his younger brother how to hide from their parents.

Wang Zhuo of the Song Dynasty would live to be eighty years old. He was knowledgeable all his life but failed in the imperial examination. He witnessed his loneliness from the Northern Song Dynasty to the Southern Song Dynasty. Many of them can be passed down to later generations.

But now, the 12-year-old poor boy looked at the sky and asked curiously: "Why is that oxygen found in so many places? Is it a lot?"

["Oxygen is indeed very important." Xiaoxiao pointed to her nose and said: "When we breathe, what we inhale is oxygen."

I dipped my hands in water and wrote O2 and then CO2 on the gray kitchen countertop.

“Oxygen circulates in our bodies and comes out as carbon dioxide.

People need oxygen to survive, and so do animals. Oxygen enters our bodies through breathing, and our blood, heart, lungs, and other tissues and organs require oxygen to function.

Plants absorb carbon dioxide and emit oxygen through photosynthesis during the day, and convert the absorbed oxygen into nutrients through respiration at night. Therefore, the air in mountains and wild areas is always better because there are more plants and they produce enough oxygen.

This is also the reason why fruits and melons in places with particularly large temperature differences in Xinjiang are so delicious. Plants have enough photosynthesis during the day and enough respiration to produce and accumulate sugar at night. ”]

Doctors understand this, so sometimes some patients have trouble breathing. They often recommend resting, talking less, and seeing fewer people, just to make it easier for them to breathe well.

It was popular in Tang Dynasty to go to the mountains and old forests to practice Taoism and become famous people: Living in the mountains has such benefits. No wonder they say why Zhongnan Mountain is so good. It turns out there is such a reason.

Farmers also understand that the things they grow need to be exposed to the sun to perform photosynthesis.

Zhao raised his head and thought of the headlights in the anchor's home, wondering whether the light from later generations could allow plants to carry out photosynthesis at night.

["Chemistryally speaking, oxygen is very active and is a combustion-supporting gas. Let's do another small experiment."]

Everyone was very excited when they heard that the anchor was going to do the experiment. Compared with boring knowledge explanations, experiments are indeed more interesting and lively.

[Xiao Xiao, who was still in the kitchen, rummaged through the cabinet, found a glass sealed jar, and took out a small scented candle and put it in.

Looking at the small lighter in her hand, she cleverly took out another long candle, lit the long one first, then reached in with the long one to light the broken candle, then quickly pulled it out and sealed the glass tube.

"Now we have sealed the pipe to prevent outside air from entering. Let's take a look inside."

The flame of the candle that was still burning gradually became smaller and smaller. A few drops of water appeared on the inner wall of the glass jar. Finally, the flame became too small and went out on its own. 】

"I understand!" Mo Weishang, the last lucky boy of the Mo family, clapped his hands and said in surprise: "Because oxygen helps combustion. The anchor closed the jar to isolate the air inside and outside, so the oxygen inside was limited. When the oxygen is burned out, Without the supporting gas, the candle will go out!”

The people around him thought for a moment and felt that what he said made sense: "But what's going on with the water on the inner wall of the jar?"

Mo Ting finally understood: "Because oxygen is O2 and water is H2O, when the candle burns, there is a chemical reaction and these elements are replaced!"

【小小又沾了点水，在台子上写下了“石蜡+氧气=（在点燃的情况下）=水+二氧化碳”的文字表达式式，又写了个“C25H52+O2→（点燃）CO2+H2O”的化学表达式。

"This formula is not a component of candles, but the main component of paraffin. I will write it like this first to facilitate understanding. Look, because it is isolated from the outside air, the oxygen inside the jar is limited. When the oxygen burns out, only Water and carbon dioxide, carbon dioxide.

So often the firewood is still there but when the fire is out, it is pulled away just to let it come into contact with oxygen. ”]

Craftsmen who have bellows at home or professional castings nod, right? When the fire is small, pulling the bellows to let outside air in will make the fire stronger. I didn't expect that this common sense that can be seen everywhere can be dismantled by chemistry in this way.

The previous ones are too difficult to understand, but these two experiments have such examples that people like them who have never studied can understand them at once.

But those who kept the principles of chemical conservation in mind quickly copied the formulas and compared them, and found that indeed all the elements were present.

["When there is a fire, the burning objects are taking away a lot of oxygen. In fact, the person first suffers from weakness of the limbs and difficulty breathing due to lack of oxygen, and then inhales too much toxic gases such as carbon monoxide, making him unable to move, so he cannot run out of the fire scene, and is finally caught. flame.

Therefore, if you encounter a fire, you must run away as soon as possible and do not stay in an environment full of flames for any longer; if possible, cover your mouth and nose with a wet gauze towel, which can effectively calm your mind and avoid solid soot, dust and harmful substances. Gas enters the body. ”]

This is indeed very useful escape knowledge. Everyone should listen carefully.

The lucky ones who had not experienced this suddenly realized that people were not burned to death by fire, but were first deprived of oxygen, then poisoned, and finally burned to death.

Shen Kuo then thought that since the next generation would understand the principles of fire so well, would there be a way to quickly extinguish fires?

At present, the first thing he can think of is to block more oxygen from entering, but the house is not a jar with a lid, and there is no way to cover it directly.

Using water is the most common method, but water is time-consuming and labor-intensive. By the time people are exhausted from pouring water, fire will almost burn everything.

"In addition to supporting combustion, oxygen has very active chemical properties and can form new compounds when combined with many other elements.

This synthesis reaction provides another effective way to produce substances, thereby helping to improve the properties of the original substance. From ordinary pig iron to various subsequent iron products, the essence is to adjust the molecular structure inside in different ways.

Oxygen can also be used to produce a variety of useful substances, such as metal oxides, oxygen generators, silicon oxide, biomass oxides, etc. It is also widely used in the medical field, such as oxygen aromatic hydrocarbon drugs, alumina drugs, Mercury oxide drugs. "

Xiao Xiao said, poured out the candle, rinsed the glass jar and placed it by the sink, then slowly jumped back while holding on to the wall.

As for chemistry, doing various small experiments is the most interesting thing. 】