Live broadcast: Ancient people accompany me to make up lessons

Before everyone could still think about wheat, they saw the anchor take out another paper.

Well, she is indeed an anchor, much more reliable than her parents, and her self-management ability is really strong.

They are used to following the anchor's hand to read the words. Well, this time it's a physics paper.

physics!

Do they remember that when they were talking about electric lights before, the anchor said that they would understand it if they learned physics later? They must learn this!

Then they jumped on the first question.

The Mo family members looked at each other, swallowed their saliva, and decided to discuss it together first.

The elder who was in charge of this group of juniors spoke first: "According to the periodic table of chemical elements, metals should refer to minerals such as copper and iron. The title says that metal overflows when exposed to yellow light, so we must first understand Are the yellow light and purple light in these choices the same kind of light?"

The young disciple's face was distorted: "Uncle, look at the CBD options. They all mention the intensity of light. We can't prove whether different lights have the same reaction."

Mo Weishang raised his hand: "I'm curious about what the frequency of light means. In terms of intensity, it can probably be compared to the light in the morning and the light at noon. It should be..."

Mo Ting: "B means that only high-intensity red light can achieve the effect of ordinary yellow light. C means that the effect of purple light is not much different from that of yellow light. If D is true, then BC is also likely to be true..."

Everyone in the discussion couldn't continue, and then looked at the anchor's pen and hesitated, and wrote A and C.

"Wait a minute, this isn't a multiple-choice question!"

They quickly looked up and found that it was really not a single-choice question, but a multiple-choice question.

"Brother, isn't this more difficult?"

"Looking at the bright side, it shows that this subject is really profound, and we should feel honored to be able to learn from the anchor."

"Assuming what the anchor wrote is correct, then there is not much difference in the intensity function of purple light and yellow light, so what is the frequency of that light?"

Except for Zhu Houzhao and Zhu Houcong, the emperors all began to lower their heads to look at government affairs. They were reminded to call them if there was something special, otherwise the end of looking at this would be the same as looking at mathematics, and the brain would be swollen.

Question 2: I don’t understand the magnet coil, next question.

[There are freely movable metal rods PQ and MN on two smooth rails placed horizontally. When PQ moves under the action of external force, the direction of current from MN to N points from M to N, then the movement of PQ may be

I am very poor in physics. I hope there are some good in physics who can teach everyone the principles.

]

It’s the track again, it’s the moving metal rod, it’s the current, and finally it’s asking about the direction of movement…

A child under the age of eight felt that this was suffering: "Brother, do we really want to learn?"

The older Mohist disciples nodded with difficulty: "In order for us to have the skills of future generations now, we must learn it!"

The Gongshu family is similar to the Mo family.

It was not enough for Gongshu Zhi to draw this picture. He quickly took out wires and wooden sticks and tried to make a model by winding them. He thought about how if this was iron, how would it move and generate electricity.

The PQ line is not in contact with MN. Will the L1 in the middle transmit electricity? If so, shouldn't it be from N to M? Why is it M to N?

After reading the confused third question, everyone felt that the fourth question about the gravity motion of a car was much more approachable.

During the math paper, a few geniuses and big guys memorized the mathematical formulas and principles of the anchor. Now that they saw this question, they started trying to solve it.

Zhang Heng's son looked at the paper full of formulas that his father quickly wrote down. He was so scared that he bravely asked: "Dad, which two are correct?"

Zhang Heng: "Do you still remember Newton's law that I said before? According to the second law, A is wrong. Look at this formula again... the car is always moving, the angle θ will not decrease, and C is also wrong."

Son: Don’t miss Dad, just keep writing.

Next, one talks about electricity, the amount of electric charge, electric field strength, and electric potential. With the vertical dot diagram, everyone can’t understand it at all. There is also a Stirling engine and Stirling cycle that everyone can’t understand at all.

However, relying on the knowledge of chemistry and the law of conservation of energy that he had learned, Jiajing felt that there must be a place for B among the correct options. The average kinetic energy of gas molecules during a certain period of time remains unchanged.

After going through the difficult multiple-choice questions, I came to the single-choice question with only three questions.

Not everyone knows the previous gravity and motion, but the last one talked about the mass of celestial bodies. He listed the condition letters in great detail. Everyone who had listened carefully in the geography class one by one picked up the data formulas they had recorded before and started to apply them. , and the mass formula was quickly derived.

Yes, yes, they were right, and so was the anchor.

There are a lot of words for the experimental questions and solution questions that follow, but I still can’t understand them, and those who don’t know them still can’t.

After finally getting through the question writing part, everyone who had been holding back questions was waiting to be asked.

[1. Qin: Zhou Shu

2. Qin: Wei Long

3. Qin: Zeng Li

4.Chinese: ginger moss

5.Chinese: Zhang Heng

6. Tang Dynasty: Wang Xiaotong

7. Song Dynasty: Ren Yongping

8. Ming Dynasty: Wei Yichang

9. Ming Dynasty: Bao Qiuchi

10.Qing: Xiang Zhong]

Zhou Shu is a disciple of the Mohist family, but he is not in Xianyang and is on his way to Xianyang.

He couldn't wait to ask: "Anchor, what exactly is physics?"

There are motion, light, force, electricity, and planets, which are much broader than chemical geography.

[Understanding how confused they were, Xiao Xiao scratched his head: "In terms of physics, the research scope is quite broad. The textbook states that the research scope covers sound, light, heat, force, and electricity. In fact, it covers everything from celestial bodies in the universe to the composition of matter. Particles, the motion laws of all matter and the basic structure of matter are within the scope of study.”

She found out the spatial scale and time scale of the physical scope to show them, but she could only go so far, and she couldn't explain it at all. 】

From microscopic particles to cosmic matter, the research scope is indeed very large, but they are really curious, how do you calculate the lifespan of elementary particles and the lifespan of the universe?

Wei Lang is a student of the Yin Yang family. He is very curious about the difference between red light, yellow light and purple light.

["They are all light, but the colors are different because the vibration frequencies of electromagnetic waves are different."

Xiaoxiao directly opened the book and showed them the contents of the spectrum.

“The wavelengths of light waves are different, and the colors perceived by the human eye are different.

The human eye can feel the color of an object, which is actually the light waves of different wavelengths transmitted or reflected by the object.

The color of a transparent object is determined by the colored light it transmits, and other colored lights are absorbed. The color of an opaque object is determined by the color of light it reflects; other colors of light are absorbed.

Take seawater as an example. The seawater we can see is basically blue, because the longer the wavelength of light, the easier it is to transmit into the seawater and be absorbed by the seawater and marine life.

Red and orange light are absorbed the most, followed by medium-wavelength yellow and green light, while short-wavelength blue and violet light are the least absorbed. ”]

Comparing the spectra in the book, it is true that red is the longest and blue-violet is the shortest.

"That's not right. Then why is it that the river water and well water we usually see are transparent and almost colorless?"

The students who listened carefully to the lecture turned around and argued: "How big is the sea? Since so much of the earth is sea water, it can certainly absorb so much red light. How big is our well water and river water? How much light can it absorb?"

Someone also came over suddenly. Aren't these red, orange, yellow, green, blue and purple the colors of the rainbow?

Zeng Li from Qidi asked: "Anchor, does the rainbow after the rain expel all the original light waves in the sun?"

"This is the prism principle. The air is moist after rain, and the atmosphere contains a lot of water vapor. The white light of the sun passes through the atmosphere and refracts seven colors of light in the opposite sky."

After Xiao Xiao explained, he found a video of the prism experiment to show them.

In the video, a person is squatting on the ground, holding a glass prism, going to the sun and constantly adjusting the angle. The shadow changes from a virtual shadow at the beginning to red and purple with two ends. When the angle is adjusted again, all the colors of the spectrum come out. 】

The Mo family, who have studied light, realized that this transparent prism not only allows light to penetrate, but also refracts light. A ray of light finally forms colors on the ground, and has been refracted several times.

The anchor's scientific explanation and this experimental video made people's cheeks ache when they saw a rainbow before, but they thought it was a strange phenomenon. But after learning, they now know that the rainbow is not a strange phenomenon, and it is good that everyone can appreciate it normally.

Jiang Tai from the Han Dynasty and Wu Dynasty had always been curious about how electricity came from in later generations. Why did the two metal pieces generate electricity when they moved?

["We also have electricity in our lives. Let me show you something interesting." Speaking of electricity experiments, how can there be no fruit batteries?

She rummaged through the cabinets, put what she found in her pocket, went to the kitchen with a cane, then went to the refrigerator and found a beautiful big apple, and split it in half with a knife.

Put half of the apple on the chopping board, and insert the metal piece in the small handle into the apple: "This is a copper piece, and this one involves a zinc piece. Now I use two iron duckbill clips with red and blue wires to clamp them in." On two metal pieces..."

Finally, connect the two wires to the small wooden board with the light bulb. Slowly, the small light bulb emits a weak light. 】

Li Tai looked up at the sky with shining eyes, and kept saying, "It's bright, she used a fruit to make the light!"

"It was the fruit that produced the electricity!" Li Chengqian, who was grabbing his clothes, couldn't care less about his stupid brother. He also felt it was magical.

Sorry, chemistry, geography, I seem to love physics more.

[Xiao Xiao explained the principle: "This actually has something to do with chemistry. Zinc flakes are more active than copper flakes and can displace the hydrogen ions of acidic substances in the fruit. This process generates a positive charge.

In order to maintain stability in the system that generates charges, electrons flow to the copper electrode through the wire, and a current is generated on the wire. ”]

Everyone who hurriedly pulled out their chemistry notes: Indeed, zinc is more active than copper and can react with things in fruit acids better. These elements themselves also have electrons...

[“Except for the fact that there is not much electricity in natural life and cannot be used by us, what we use every day is the generated electricity.

Generating electricity requires magnets as well as coils to produce electricity. Magnets have a magnetic force that attracts metals such as iron. The range that this force reaches is called a magnetic field.

By moving the coil in this magnetic field, the coil generates electricity. In a strong magnetic field, if the coil cannot be moved and the magnetic force is not changed, electricity cannot be generated.

This principle is called electromagnetic induction, and the current generated is called induced current. "

Xiaoxiao knew what was interesting, so he found a video of someone else making a homemade hand generator and showed it to everyone. 】

Science enthusiasts and craftsmen from all dynasties: Thank you anchor!

First build a frame with a few small pieces of wood, which is easy to do. They can grind and make the gears and connecting sleeves by themselves. The technical difficulty is not bad. The motor is a bit more difficult, but the perspective diagram and principle are explained. The difficulty is It's a bit difficult, but it's easy to do once you have the direction.

Finally, there are the copper wires, iron sheets, and magnets that need to be used inside. These things are more difficult to get, and they have no electrical appliances, and there is no light bulb to light up when the electricity is generated.

Not to mention professionals like the Mohists and Gongshujia, government craftsmen and later private craftsmen also felt that this was very difficult to do. It was either that it couldn't be done, or that some materials were really difficult to work with.

Watching the completed small generator turn on and the lightbulb light up, everyone realized in hindsight that the previous Three Gorges Project should have used water energy to do similar things.

No hand cranking is needed to convert the potential energy of the water flow at such a high height into electrical energy. The high-altitude iron towers and thick black wires all transport this kind of electricity.

Zhang Heng reported all the nouns he had recorded and asked the anchor about their concepts, symbols, and formulas.

[Xiao Xiao read the list and began to explain it one by one to the real boss;

"Hooke's law means that within the elastic limit, the elastic force of the spring is proportional to the elongation (or compression) of the spring..."]

Wang Xiaotong, a mathematician from the Tang Dynasty, rode in Zhang Heng's car, wrote down a bunch of professional terms and formulas, and asked the anchor if he could explain how she calculated the refractive index of glass.

When the anchor finished explaining the handwritten drawings and calculations, Ren Yongping, a liberal arts student in the Northern Song Dynasty, had had enough of hearing: "Anchor, may I ask what atmospheric pressure is?"

He had always remembered this word since geography, and now he had the opportunity to ask.

"If you take a bath or swim, you should be able to clearly feel the various pressures caused by the water surrounding your body after entering the water.

Let’s first introduce the atmosphere, which consists of the troposphere, stratosphere, mesosphere/ionosphere and exosphere.”

Xiaoxiao drew a picture and explained to them the approximate height and characteristics of the standard gas layer.

“Atmospheric pressure is created by the weight of the air in the atmosphere, remember what we said before about Earth’s gravity?

On the surface of the Earth, there are a large number of gas molecules above the atmosphere. These gas molecules are affected by the gravity of the Earth, thus exerting a pressure on the surface of the Earth. This pressure is called atmospheric pressure and is usually measured in standard atmospheric pressure atm or Pascals.

As altitude increases, the thickness of the atmosphere decreases and the number of gas molecules decreases, so the pressure decreases. At sea level, the standard atmospheric pressure (T=273.15K) is 101.325Kpa,"]

Li Jing understood why all the soldiers felt uncomfortable when they went to Tibet.

They were acclimated because they suddenly went from a place with high atmospheric pressure to a place with low atmospheric pressure. The air they inhaled in their lungs was different from usual. No wonder they all felt so uncomfortable.