A Man of Science and Engineering in Troubled Times Wandering in the Late Qing Dynasty

Chapter 517 Spectrum
As the honorary principal, Li Yu would definitely teach them a lesson whenever he had the chance.

It seems a bit arrogant to say it, but looking at the current situation, at the level of theoretical foundations of physics, there are really few people who can surpass Li Yu.

Li Yu has taken some classes in China before, and most of them only taught middle school content. Now it is the first time that he has really taught something that should be taught in universities in China.

At this time, the content of university classes was not as fixed as in later generations. The main reason was that there were no fixed textbooks, and professors basically relied on themselves to produce lecture notes.Therefore, during the Republic of China, the requirements for university teachers were actually quite high, and at least they could not just follow the textbook.

Li Yu deliberately guided them to understand some of the most cutting-edge things so that they could find research directions more quickly when they study abroad in the future.

There are relatively few students now, so in large classes there will be situations where many students from different majors come to listen - Li Yu is now such a famous name in the scientific community, so sometimes Li Yu cannot speak too in-depth, but it must be profound Necessary basic content of knowledge.

Only in the physics department can I talk about my specialty.

What Li Yu told them today was about differential equations, which are important in mathematics and physics.The handouts were naturally handwritten by Li Yu and then printed and distributed.

"I hope you don't dislike my fonts," Li Yu said. "Besides, the smell of this kind of ink printing is quite good to me sometimes."

Xie Yuming said: "Most of them are English symbols, and there are not many Chinese characters. At least in my opinion, Principal Li is already very good at English calligraphy."

"Thank you for the compliment," Li Yu said with a smile, "Then let's get started. Today I hope to broaden your horizons and understand the brilliant progress in atomic physics in the current physics community."

Xie Yuming said: "You mean, in just a few years, the West has made a very big breakthrough in physics?"

Li Yu nodded: "Yes, we are actually in a period of great explosion of physics. I hope that some of you can catch up with this wave as soon as possible."

Xie Yuming said: "The book I read said that physics has only tinkering work left, and it is a very complete subject."

"The book you are reading is already out of date," Li Yu said, "but it doesn't matter, we still have time."

Li Yu wrote on the blackboard for a while, and then said: "What I talked about today will be of great interest to you. It is a spectroscopy result in the atomic field in recent years, from the German physicist Stark. It is worth noting that , and he also used quantum theory, so it’s somewhat difficult.”

What Li Yu wants to talk about is the Doppler effect of atomic spectra discovered by Stark four years ago.

Regarding Stark, let me introduce a few words. He has since become a "German physicist". He is the same person as Leonard, both worked for the Nazis, and are Einstein's mortal enemy.

But in terms of physics, especially experimental physics, both Stark and Leonard are at the top, and their level is quite high.

Starting from college, Stark took only three years to get his doctorate.This kind of speed will be almost impossible in future generations, but at present, it is not a particularly unusual thing. Both Planck and Boltzmann obtained their Ph.D.s at the age of about 21.

Talking back to Stark's research, he used a very clever experiment to demonstrate a question that troubled the physics community a few years ago: Are atoms or ions emitting light?

Modern people will definitely be able to give the answer at once: atoms and ions can emit light.

But this issue was not known to the academic community before 1907.

Stark's idea is very strange, which is to use the Doppler effect: ions will have a speed in the electric field. If the ions emit light, the frequency of the light emission is related to the speed of the ions;

And if atoms emit light, since the atoms are electrically neutral and will not be accelerated by force in the electric field, the frequency of the light will not change.

Then based on the red shift and blue shift phenomena, conclusions can be drawn.

Stark used this principle to design experiments and discovered that atoms and ions would emit light.

The specific process is really quite ingenious.

Not only that, but Stark also relied on his excellent physical intuition to discover that there was almost no luminescence in the area close to the static spectral line: the closer to the static spectral line, the smaller the speed of hydrogen ions.

Stark suspected that low-speed hydrogen ions would not emit light.Then about this, Stark gave an explanation relying on Planck's quantum theory.

And once it comes to Planck's quantum theory, it tests your mathematical skills.

After all, even Planck often spoke of his quantum theory as a complex mathematical tool.

So what Li Yu is talking about now is really not simple. After talking for a while, Li Yu himself stopped.

"It must be some damn mathematical transformation. I can't remember it at the moment." Li Yu concentrated for a moment, "Can anyone here see it?"

No one could tell, no doubt.

Li Yu continued: "Then let's jump over first and not waste time for now."

Less than 10 minutes later, Li Yu suddenly stopped while explaining the following content and said, "I know what's going on!"

——Years later, Xie Yuming and other people who had taken Li Yu’s courses praised him: “Although the topics of his discussions were complex and changeable, he still found time to reflect on the physical essence of special mathematical transformations. His mathematical foundation is so deep that it is amazing. "

"Look, the error is here," Li Yu said, pointing to some inconsistent data. "The connection between physics and mathematics is so wonderful. It requires not only wild imagination, but also very detailed calculations and derivation."

Xie Yuming was stunned, and then suggested: "Do you need to write to Professor Planck and Professor Stark to point out this error to them?"

"We don't need to tell him that he made a mistake," Li Yu said easily. "The result is correct, but the proof is wrong. We only need to write to him and tell him what the actual proof should be. Because what matters is the content, not the math."

Xie Yuming finished copying Li Yu's blackboard writing: "I think it will take me several days to digest these contents before I can understand them."

Li Yu said: "Study slowly. They are all key contents of atomic physics. If you work hard enough in the future, you can make new results."

Li Yu had his own purpose in talking about Stark's spectrum experiment today.

In another two years, Stark would discover the Stark Effect that bears his name.

The explanation of the Stark effect has since been extended to many versions, and many big names in quantum mechanics have participated in it.For example, Bohr, Epstein (not Einstein), Schwarzschild, Pauli, Schrödinger, etc.

In short, this is a very challenging content, and it is also a topic that is enough to make a name in the scientific community.

It's just a little difficult.

In Li Yu's era, the Stark effect and the Zeeman effect were not mentioned much in university physics majors, and were basically brushed aside. However, the importance of these two things in the history of quantum mechanics is not low.

These two contents can be used as the final level of the postgraduate entrance examination for physics majors, focusing on one that is difficult to understand + difficult to calculate.

Li Yu intended to let Xie Yuming learn more about this field. Anyway, it was already his main field, and it would help him establish a greater reputation in the physics community in the future.

When Li Yu clapped his hands and left class, he saw Lu Xun and two middle-aged men standing outside the door.

"After listening to your lecture on campus today, I finally felt the academicians' supreme achievements in science!" Lu Xun said, and then introduced the two people beside him, "These two are Mr. Lu Feikui and Mr. Shen Zhifang , after they heard that Mr. Academician was the president of the Industrial Association, they came to pay a special visit."

Li Yu said, "Nice to meet you. Let's talk in the office."

Sitting down in the office, Lu Feikui said: "Now that the Revolution of [-] has been accomplished, the whole country is happy, and everyone knows the importance of education. We are going to open a bookstore." Li Yu said, "What a good thing!"

Lu Feikui said: "We are going to name the bookstore Zhonghua Bookstore and publish the newly compiled "Zhonghua Textbook". We hope that Academician Li Yu can help correct it."

Only then did Li Yu realize that this year happened to be the founding year of Zhonghua Book Company. Lu Feikui and Shen Zhifang were the founders. They were both from Zhejiang and fellow villagers of Lu Xun.

Li Yu said: "I will do my best to help."

Shen Zhifang said: "It would be best to have your help! Nowadays, the dynasty has changed, and the ideological changes have been earth-shaking. We are ready to learn from Mr. Cai Yuanpei's aesthetic education ideas and replace the past decadent imperial education concepts in textbooks."

Li Yu said: "Then I have to support it even more. Nowadays, scholars are actually quite hesitant and need to find a goal in their hearts."

Lu Xun said: "Can Minister Cai's aesthetic education achieve this goal? According to Minister Cai's philosophy, aesthetic education is better than Western 'faith' or religion, one is free and the other is compulsory; one is progressive and the other conservative; one is universal and the other is bounded .”

Aesthetic education is Cai Yuanpei’s famous educational philosophy.

Li Yu said: "It is indeed worthy of promotion, but I hope you will also add a basic thing to the newly compiled textbooks."

Lu Feikui said: "Please give me some advice, Mr. Academician."

Li Yu said: "It's very simple, science and democracy."

Lu Xun first praised: "Good!"

The changes at the end of the Qing Dynasty and the beginning of the Republic of China were really too great for the Chinese people. In the spiritual field and academic thought, they were also faced with "the Taoism that divided the world" and "great catastrophes and strange changes unprecedented in the ages."

For intellectuals, the positioning of ideas is also very important.This is an important hidden thread hidden in the torrent of history.

A few years later, the science and democracy of the New Culture Movement were obviously more advanced.

Lu Feikui said: "We will incorporate this concept into textbooks to influence more readers."

Zhonghua Book Company was the second largest publishing organization after the Commercial Press in the Republic of China, especially publishing a large number of textbooks.

If we really count, no matter what era, textbooks are the books with the largest circulation, and they are also the books with the greatest influence.

Today is an era when Europe, the United States and Japan are desperately trying to control the minds of Chinese scholars, and textbooks need to be protected even more.

Li Yu said: "I will provide funds to help you with a series of steps from compilation to revision, publication and distribution."

Lu Feikui said: "I'm so grateful to Minister Li!"

Li Yu said: "You're welcome, books are the ladder of human progress. What else is more important than this, fighting for power and profit?"

Lu Xun laughed after hearing this and said, "I'll just say that Academician Li is different from ordinary people."

Lu Feikui said: "As expected, as expected!"

Li Yu said: "I will contact the Commercial Press and let us compete in a healthy way and work together to promote the update of educational books."

Zhang Yuanji has also been very busy recently. After the Revolution of [-], he kept in contact with the revolutionaries and prepared for the great development of education in the early Republic of China.

Zhang Yuanji also knew that once the Qing emperor abdicated, many textbooks would have to be rewritten, and the idea of ​​loyalty to the emperor would have to be eliminated.

Then, in order to adapt to scientific education, he also planned to add a museum department and an ironwork manufacturing department to manufacture standard models, instruments and displays.

These are also what Li Yu is very concerned about, and he will provide more money to support them in the future.

Li Yu suddenly remembered: "Teacher Zhou, have you received an order from Mr. Cai Yuanpei to join the Ministry of Education?"

Lu Xun nodded: "As expected of a radio operator, the information is so convenient."

Li Yu said: "When you have time, how about coming to my school to be a part-time professor?"

Lu Xun was surprised and said: "I'm afraid my academic qualifications are not up to standard."

Li Yu said: "Heroes don't care about their origins, and your academic qualifications are not bad."

Lu Xun said: "Your school has high aspirations, but I am worried that my level is not enough."

"Enough, enough, that's enough! If you don't have enough, then there won't be many people who have enough." Li Yu said with a smile.

Lu Xun wondered: "You want to talk about physiology and medicine?"

Li Yu said: "It's up to you, even if it's about literature."

Lu Xun said: "Literature? It's not my strong point."

This time it was Li Yu's turn to laugh, "Who can say for sure."

Lu Xun, the second monk, was confused: "I don't understand what you are going to say."

Li Yu said: "In short, just agree. After all, you are an official of the Ministry of Education appointed by Minister Cai. This matter will not be difficult for you."

"I hope it won't turn into a show of shame." Lu Xun had no choice but to reply.

Li Yu said: "As long as we talk about aesthetic education, science, and democracy, there is no such thing as showing off one's ugliness."

Lu Xun said with emotion: "I didn't expect that after I returned to China, I would really form an indissoluble bond with education. I remember when I was a child, I studied at the Road and Mine School, and when I rode through the flag camp, I was always bullied by the banner people. Now that times have changed, I don't even In order to ensure the special status of bannermen, we must be scientific and democratic.”

Although Lu Xun agreed, he did not have the opportunity to give lectures in Shanghai for the time being, because he would soon receive an order to go north to Beijing.

Yuan Shikai wanted to transfer various core departments from Nanjing to Beijing, under his nose.

The Revolutionary Party really has no choice but to let him go when faced with such an old official.

Fortunately, Mr. Sun and others had some backup plans and drafted a "Temporary Agreement" in advance to restrain Yuan Shikai.

In addition, Yuan Shikai's right-hand assistant Tang Shaoyi also had a rift with Yuan Shikai at this time and joined the Alliance. It can be said that it seriously affected Yuan's control of the current situation.

Yuan Shikai naturally knew the importance of education, so he changed the Qing Academy to the Ministry of Education, accepted people from Nanjing, and still made Cai Yuanpei the Minister of Education.

(End of this chapter)