1. The study of the history of physics is of great significance. Generally speaking, physics is a basic discipline in natural science and is at the core. A very important part of the history of science is the history of physics. Therefore, studying the history of physics helps to clarify the laws of scientific development and helps to understand the relationship between science and society, the relationship between science and technology, and the relationship between science and philosophy. From the perspective of studying physics, understanding the development of physical concepts and theories can not only deepen the understanding of these concepts and theories, but also further understand the characteristics of the subject of physics. As a future physicist or scientific and technological worker, we should grasp the development trend of physics, understand its trends, and consciously promote the advancement of physics. When talking about the significance of the history of physics, Professor Yang Zhenning, a famous Chinese-American physicist, said: "There are some problems in the development of physics in China. Based on my general contact, I have the impression that in the past few years, there was little attention paid to foreign things. I want to know, but the result is that I am a bit confused and confused. In fact, some of the things introduced are just noise in the development process and disappear in a blink of an eye.

"The result is that the ins and outs of things are unclear. The main development is unclear. However, without understanding the development of the main body, it is not easy to cultivate students with unique insights. They will always be moving around with a lot of noise. There are so many students studying theoretical physics in China now, too many. I think they have little chance of success. I think it would be more meaningful if we could actually give some practical introduction to foreign developments. ”①

Physics, like other natural sciences, is in development. Yesterday’s things are history. Understanding the past is to grasp the context of development, predict future trends, and thus correct ourselves. Mr. Yang Zhenning’s speech is of great practical significance to us physicists and deserves our deep thought.

2. When studying and studying the history of physics, we must pay attention to historical data and not take it for granted. We must proceed from historical facts and find conclusions from the analysis of historical data. The history of physics is a science. We must have a scientific attitude, seek truth from facts, avoid being subjective and arbitrary, and promote a rigorous style. Only in this way can the history of physics truly play a guiding and reference role. This is of practical significance to those engaged in the history of physics, and should also be noted by learners and researchers in any related disciplines.

3. Studying the history of physics cannot replace the study of the subject, but can only serve as a supplement to undergraduate study. Physics courses are basically told in a logical system, while the history of physics is arranged in historical order. . Add some vertical connections to the horizontal connections to make our knowledge three-dimensional, and the knowledge will inevitably be deepened and broadened. This supplement is indeed valuable, but it must not take over the subject, otherwise it will turn the cart before the horse and become rhetoric. The original intention has been lost.

Fourth, learning the history of physics should not be satisfied with adding some historical knowledge. It is not just to deepen the understanding of physical concepts and laws, but more importantly. It is to find viewpoints, methods, and examples from the development of physics, and to be inspired by the experience of previous generations. For this reason, our learning should be:

(1) Rely on self-study and rely on your own collection. Materials, own research, and independent thinking:

(2) Focus on analysis and conduct academic debates to broaden your thinking. Do not turn the teaching of the history of physics into a cramming style, memorizing articles and following what others say.

(3) Pay attention to learning to use historical methods. Historical methods are one of the important methods of scientific research. Collecting and analyzing historical data is a basic skill for every young person when doing a dissertation. You must first make a historical review and development overview of the subject to explain the significance of your work. This is the historical method. Studying the history of physics can help you master this method.

5. Looking for ideas is to learn what ideas dominated the advancement of science. Why do they study these issues? How do they deal with the differences between theory and experiment? What is the goal they strive for? For example: We can ask: What is the goal they pursue?

(1) The unity of nature is attributed to Newton. And the force at a distance, he unified the attraction of celestial bodies and the gravity of the earth, and attributed it to universal gravitation. Although the unity between universal gravitation, electric force, and magnetism was not found, it inspired future generations to discover the inverse square law of electric force and magnetism. Oersted's discovery of the magnetic effect of electric current in 1820 was not accidental, but was influenced by a scientific trend of thought in the 19th century, which believed that natural forces are unified. He said in 1803: "Our physics will no longer be a fragmented collection of motion, heat, air, light, electricity, magnetism, and any phenomena known to us, but we will contain the entire universe in one system ” He has been looking for the connection between the two natural forces of electricity and magnetism, and finally observed the magnetic effect of electric current in the experiment.

Faraday also firmly believed in the unity of natural "forces". Driven by this idea, he discovered the effect of magnetic fields on optical polarization planes in 1845 after several setbacks. This was the first magneto-optical effect and played a considerable role in the development of electromagnetic theory. Because this phenomenon shows that there is indeed some connection between electricity, magnetism and light.

He also believed in the indestructibility and transformability of physical "forces". Although he was unsuccessful in exploring the connection between electricity and gravity, his ideas were thought-provoking. Whether universal gravitation, electromagnetism, and several other forces, such as the weak interaction and the strong interaction, can be unified is one of the major topics in contemporary physics research.

(2) The second goal pursued by physicists is the universality of natural laws. Such is the understanding of the law of conservation, for example. The concept of conservation has existed in natural philosophy since ancient times. Laws (or principles) of energy conservation and conversion, mass conservation and mass-energy conversion, momentum conservation and angular momentum conservation, etc., are all the results of in-depth development and comprehensive research in physics, and the essence of conservation lies in symmetry, for example:

Time translation symmetry (invariance) leads to energy conservation;

Space translation symmetry (invariance) leads to momentum conservation;

Space rotation symmetry (invariance) ) leads to the conservation of angular momentum;

The symmetry (invariance) of the electromagnetic field under gauge transformation leads to the conservation of charge, and so on.

With the deepening of research, people have found that lower-level symmetries often evolve to higher-level symmetries, and the corresponding lower-level conservation laws are often not conserved outside certain conditions. It needs to be merged into higher-level conservation laws, such as:

Conservation law of mechanical energy → Law of energy conservation and conversion → Mass-energy conversion relationship;

In 1956, Li Zhengdao and Yang Zhenning discovered the universe. Said non-conservation→CP joint conservation;

In 1964, Cronin discovered that CP joint non-conservation→CPT joint conservation.

From low level to high level, from special to general, from outside to inside, from rough to fine, this is the law of evolution of physics.

(3) The third goal pursued by physicists is the unification of theory and experiment. There is a rule in physics that the objective criterion for testing a theory is nothing else but experiment. Many physicists are often skeptical of new theories as they emerge, but then switch to the new theory's side once it is experimentally confirmed. However, it should also be pointed out here that not all experiments are correct. Individual experiments will inevitably have errors or unexpected errors, which must be treated with caution. Einstein took the correct attitude when dealing with Kaufmann's experimental results of electron mass changing with velocity. There is nothing wrong with the statement that experiments are the standard for testing theories and should be understood comprehensively. The standard for testing a theory does not refer to a specific experiment. Rather, it should be said that the experiment as a whole plays a testing role in the theory.

6. Finding methods is to learn from the innovative activities of senior scientists how to deal with problems. For example:

How did they seize new topics, thereby grasping new trends in scientific development, discovering new laws and new phenomena;

How did they learn from their predecessors and summarize the experiences and lessons of history? , thereby finding new ways;

How they deal with contradictions and find breakthroughs from contradictory oppositions;

How they design new experiments to obtain decisive experimental results.

Specific research methods are also worth learning:

Contrast method is a commonly used method to explore the laws of new phenomena. People use transplantation methods to greatly speed up the development of emerging fields;

Ideal experiments are an important means of scientific reasoning, and proof by contradiction is also a powerful tool for logical reasoning.

There are many methods. In order to achieve a certain goal, you can use this method or that method. Make the best use of the situation and prescribe the medicine dialectically. Through the study of the history of physics, you can make comparisons and use them. I draw lessons from the activities of my predecessors so that I can refer to them in the future when needed. If you pay attention to study and research in normal times, when the critical moment comes, it will have its due effect. G.P. Thomson, one of the discoverers of electron diffraction, pointed out: "There are many reasons to study the history of science. The best reason is to see how scientific discoveries are made from typical examples. We need to know many examples, because there are various roads , it’s hard to find any shortcuts.”

7. Looking for role models, of course, includes looking for typical figures from various typical cases, citing them as your own role models, and setting them as your own role models for learning. What I am referring to here is a broader meaning, including both a scientist’s research and entrepreneurship, and his conduct as a person. Great scientists are also human beings. They grow up and have their own growth process. Their growth path has special reference value for students and teachers. Scientists also have their own joys and sorrows. His attitude towards difficulties and adversity, his views on reputation and status, his perseverance and tenacious struggle, his flexible style, his keen observation and sharp insight, his love for the motherland and the people, his Dedication, etc., are all worthy of our study and reference.

The power of role models is huge. Of course, we can abstract the unique elements of their success and refine them into a few mottos, but the important thing is not the ready-made conclusions, but the real experience and turning them into our own creed. So you should learn from the experience yourself and truly be convinced. It is best to get to know one or two or several physicists in depth, follow their examples, and try to follow their examples in your own practice, so that you can get the power to inspire yourself.

Li Yuanzhe, winner of the 1986 Nobel Prize in Chemistry, said that he used to love reading biographies of scientists, and he was particularly moved by Marie Curie.

Yang Zhenning said in a speech: "My classmates often ask me what are the factors for success in physics work? I think the factors can be summarized into three Ps:

Perception, Persistence, and Power.

"Perception" - Persistence, if you see something right, hold on to it;

"Persistence" - Persistence if you see it right;

"Power"——Strength, with power you can get through obstacles, and you have to get through difficulties when you encounter them." ①

Einstein has a famous saying that everyone may have known for a long time. Someone asked him the "secret" of success, and he wrote a formula:

A=X+Y+ZA It stands for success, X stands for hard work, Y stands for the right way, and Z stands for less empty words. This formula summarizes Einstein's scientific career.

Weinberg, one of the winners of the 1979 Nobel Prize in Physics and one of the proposers of the electroweak unified theory, said: A very important quality for physicists is "offensiveness" - the attack on nature. "Offensive".

Studying the history of physics will give you a deeper and more comprehensive understanding of scientists than reading their biographies, because in this way you can understand the scientist's life and his activities from the historical background of scientific development. and the role he played. We must correctly understand the historical role of figures, not blindly worship them, and not mystify great scientists, thinking that they are beyond our reach and unattainable. They are indeed smarter than us, but it is not impossible to learn. Of course, if you learn, you may not have the opportunity to make such a great contribution, but their spirit can always be applied to various positions and guide you to do things according to your own conditions. produce corresponding achievements.

The last point is to put yourself into it so that the study of the history of physics can form a driving force for your progress.

Studying the history of physics should give you a sense of intimacy, as if you were actually there. Those historical figures and events come alive before you. You can ask yourself, what would I do if I were in that era and encountered such a problem, or what should I do if I encounter a similar thing today?

Of course, due to different times, the situation of our predecessors will be quite different from ours. But as long as you use a historical perspective and make a proper analysis of historical conditions, you can still draw wisdom from them.

Studying the history of physics can broaden our horizons and make our minds active.

Studying the history of physics should also be connected with our own mission. Our recognition of the relationship between science and society will naturally increase the sense of urgency in developing our country's scientific undertakings. We in China started later than others, so we should study the history of other people's development and understand the paths they have taken so that we can catch up and not make the same mistakes that others have made.