Before the 20th century, people thought that no matter what scale was observed, the observed substances should be the same. Back in ancient Greece, a group of philosophers once thought: What would happen if an object was cut into small pieces and this process was repeated indefinitely until it was too small to cut (atoms)? They assume that atoms are the epitome of what we observe. For example, the atoms of cheese are no different from a whole piece of cheese, except that they are smaller in size. But quantum theory subverts our traditional cognition. When we try to explain the microscopic units in the world such as photons, electrons and atoms in the modern sense, we can't directly feel their existence through our senses.

When people realized the existence of quantum level, historians of science began to exaggerate this shift as a "paradigm shift". Suddenly, scientists' world outlook changed. Before the quantum revolution, scientists thought that atoms (assuming the existence of atoms-before the 20th century, many scientists had reservations about the existence of atoms) were infinitesimal spheres of the matter they constituted. Quantum physics points out their differences. For example, a piece of graphite is completely different from a diamond, but the graphite or diamond is filled with the same set of carbon atoms. Quantum activity is strange, but it doesn't mean that people who don't get a doctorate in physics can't understand it and stay away from it. I have been teaching the basics of quantum theory to children around 10. I don't teach them mathematics, and I don't need any mathematical calculations to understand quantum theory. What students need to do is to put aside doubts, because quantum activities always play cards against common sense.

Richard feynman, a great quantum physicist in the 20th century (which I will introduce in detail later), once said in a public speech, "Do you think you will understand if I tell you my knowledge? No, you don't understand. In that case, why should I continue to give you lectures? Why do you find it difficult to understand my class and spend so long sitting here listening to it? My task is to advise you not to leave because you don't understand. In fact, my physics students are also difficult to understand. Because I don't understand it myself. In fact, no one knows. "

On the surface, it seems that Professor Feynman lost interest in the audience because he said it was difficult for students to understand his lecture. At the same time, Professor Feynman also claimed that he didn't understand quantum physics. In contrast, my theoretical research is not as good as Professor Feynman's, but I am teaching quantum theory to children aged 10, which seems difficult to explain. In fact, Fei added after talking about the last paragraph: "It's not that the audience can't understand the big events in the quantum field or some phenomena described in quantum physics, but that no one can understand why it happened in the form it happened. In addition, it is so unreasonable that it has caused us great trouble to understand it. " As far as quantum theory is concerned, children aged 10 may be more acceptable than adults, which is also an important reason why I think this course (and relativity) should be offered in primary schools.

Professor Feynman went on to say, "Next, I will introduce you to the concept of nature. If you don't like the content of this paragraph, it may hinder your understanding of nature in the future ... Quantum electrodynamics (the theory of unifying light and matter) describes nature as a fallacy from common sense. And this is completely consistent with my experiment. Therefore, I hope you can accept the essence-fallacy. " We have to accept and admit the point put forward by the novelist D.H. Lawrence (though he is not a fanatic of quantum theory): He likes quantum theory because he doesn't know it at all.

This article ends. I will continue to explain it to you next time.