People call objects composed of a large number of molecules, atoms and photons as macro objects, such as particles described by Newtonian mechanics, electromagnetic fields (or light), and so on. The sum of these macro objects constitutes the macro world of physics research. The laws that the macro world meets are called macro laws. Classical mechanics, classical electromagnetic theory and classical statistical theory are all theories describing the macro world. On the contrary, people refer to molecules, atoms, atomic nuclei, protons, neutrons, electrons, photons, etc. as microscopic objects. The physical laws that microscopic objects follow are called microscopic laws, which are very different from macroscopic laws. The objective material world that conforms to the micro laws is called the micro world. Quantum theory is a theory that describes the micro world. [1]
Quantum theory is one of the two cornerstones of modern physics. Quantum theory provides us with new ways of expression and thinking about nature. Quantum theory reveals that microcosmic The basic laws of the material world are Atomic physics , solid state physics Nuclear physics And particle physics. It can be explained well atomic structure Regularity of atomic spectrum, properties of chemical elements, absorption and radiation of light, etc. Study on blackbody radiation
Thermal radiation is a new discipline developed in the 19th century. Its research has been supported by thermodynamics and spectroscopy, and new technologies of electromagnetism and optics have been used, so it has developed rapidly. At the end of the 19th century, another gap was opened in this field, namely, the research on blackbody radiation, which led to the birth of quantum theory. In order to find out that Blackbody radiation law Many physicists have made various attempts. Study on photoelectric effect
In 1905, Einstein published his famous paper "A Tentative View on the Generation and Transformation of Light" in response to the difficulties encountered by the classical theory in explaining the photoelectric effect. In this paper, Einstein summarized the history of the long controversy between the particle theory and the wave theory in the development of optics, revealed the dilemma of classical theory, and put forward a new viewpoint on the basis of Planck's energon hypothesis—— light quantum hypothesis 。 The work of Planck and Einstein has an important position in the history of physics, but it is Bohr who makes a profound impact on quantum theory.
In 1913, Niels Bohr, a Danish physicist and a major scientific thinker in the 20th century, once again made a very beautiful use of Planck's theory. Starting from Rutherford's nucleated model, Planck's concept of energy son and achievements in spectroscopy, he obtained many discrete and stable "weird" rules of energy level and spectral frequency that nature actually obeyed with considerable accuracy, thus successfully solving the stability problem of atomic nucleated structure and explaining the spectrum of hydrogen atom excellently. Later, the hydrogen spectrum experiment of E.J. Evans confirmed Bohr's prediction of Pickering spectral lines. H.G.J. Moseley measured the X-ray identification spectral lines of various elements and proved that they had certain regularity, which provided strong evidence for Rutherford and Bohr's atomic theory. [2]
