What is classical physics? What is Classical Physics?

Encyclopedia Classical Physics is divided into categories according to the characteristics of the development of physics itself.

The development of physics is divided into several periods, and some characteristic characteristics are identified in each period. This is mainly based on the internal logic of the development of physics, and the use of this periodization principle can not only take into account the influence of social production and socio-economic forms, but also reveal the internal laws that run through the development process of physics.

In accordance with the law of the development of physics itself, combined with the characteristics of various social and economic periods, and considering that different periods have different research methods, the history of the development of physics is roughly divided into three periods.

Clause. 1. The embryonic period of empirical physics (before the 17th century).

During this period, China and ancient Greece formed two cultural centers where the East and the West complemented each other. The empirical sciences have gradually diverged from productive labor, and the main methods at this time are intuitive observation and philosophical speculative speculation. Knowledge of astronomy, force, heat, sound, and light (geometric optics) related to production activities and people's own direct senses was first developed.

With the exception of Greek statics, China was in the lead at the time in all of these aspects.

Clause. 2. The period of establishment and development of classical physics (early 17th century to late 19th century).

At this time, capitalist production promoted the development of technology and science, and formed a relatively complete system of classical physics. A combination of systematic observational experiments and rigorous mathematical derivation was introduced into physics, leading to the "scientific revolution" of the 17th century, mainly in the fields of astronomy and mechanics. The establishment of Newton's mechanics system marked the birth of modern physics.

After preparation in the 18th century, physics gained rapid and important development in the 19th century. Finally, at the end of the 19th century, the development of classical physics reached its peak with classical mechanics, thermodynamics and statistical physics, and classical electromagnetic field theory as the pillars.

After Einstein's theory of relativity was proposed, the absolute time and absolute space of classical physics were completely broken, and classical macroscopic physics entered the stage of cosmic space.

Later, with the deepening of quantum mechanics, it was found that the theory of relativity and quantum mechanics were not unified at the microscopic level, and there was a defect of failure at the singularity, so the theory of relativity was also included in classical physics.

The splendor of classical physics in the 19th century.

Classical physics is a mechanical system with classical mechanics, classical electromagnetic field theory and classical statistical mechanics as the core. Newton, Galileo and others basically formed the classical theory of physics in the 17th century, and in the following centuries, the classical mechanical system developed rapidly and reached its peak. But with the development of science, scientists began to discover the local phenomena of classical mechanics.

The discovery of the microscopic world and the speed of light allowed scientists to discover that the classical mechanical system was not applicable in the state of high-speed motion and the microscopic world, so the theory of relativity and quantum mechanics began to gradually take shape, forming the basic theory of modern physics.

1. Classical physics theories, applicable to our daily life:

Classical physics theories were born in the early days, when scientists could not achieve high-speed motion, nor could they make detailed observations of astronomical phenomena, so the scientific theories obtained were often in practical life, such as common conservation of kinetic energy, friction problems, etc., these are the best in life, in addition, the discovery of gravity, let human beings go from the earth to space, providing a theoretical basis for space exploration.

However, as scientists learn more and more knowledge, many problems arise in classical physics, such as the fact that the mass of an object is not fixed in a high-speed motion state close to the speed of light, which challenges Newton's formula of kinetic energy in classical mechanics.

After scientists discovered the microscopic world, they also discovered that the motion of particles in the microscopic world is basically not controlled by classical physics, and the development of science urgently needs a new set of theories.

2. The theory of relativity explains the laws of motion of high-speed objects, and quantum mechanics solves the laws of motion of the microscopic world

The emergence of the theory of relativity has greatly subverted world physics, and classical physics is a theory full of limitations in the view of relativity. After the advent of the theory of relativity, Newtonian classical mechanics began to be limited to explaining macroscopic and low-speed moving objects, while the theory of relativity could explain the laws of motion of objects at close to the speed of light.

However, there is no right or wrong in science, and to this day, Newton's classical mechanics is still a classic of scientific theories, and it is also the knowledge that all students must master and learn.

Classical physics, compared with modern physics, is a scientific theory that is closer to daily life, and we only need to understand classical physics in daily life to explain most of the phenomena.

However, when human beings go to space, facing ultra-high-speed moving objects and supermassive celestial bodies, the theory of relativistic three-dimensional space and four-dimensional space composed of one-dimensional time can help scientists explain various mysterious phenomena in the universe.

Classical physics is a traditional theory of physics, and it is also based on the research of some physicists.

Classical physics is the Newtonian physics we learned in junior high school, which studies the laws of macroscopic physical motion, which is mainly different from Einstein's general and special relativity theories.

It's about managing certain substances, so that you can understand some substances very well, which is particularly important, and you need to understand.

Classical physics includes:Classical physics consists of five parts: force, heat, light, electricity, and primitive (atomic physics).

1.Newton. It is the sum of classical physics, such as Maxwell's electromagnetic waves.

Theory, Joule and Carnot's Theory of Thermals, Ampere.

and Ohm's theory of electricity, etc., have made great contributions to the development of classical physics.

2.The counterpart to classical physics is modern physics, which mainly includes quantum theory, which studies the laws and effects of the motion of matter in the microscopic world, and the theory of relativity, which studies the laws and effects of the motion of objects at high speeds (close to the speed of light).

Classical physics is a basic theory that deals with physics, which deals with the basic principles and laws of physics, as well as the relationship between them.

It is the foundation of physics, the basis of the study of physical phenomena.

Classical physics includes mechanics, thermodynamics, electromagnetism, optics, quantum mechanics, etc.

Mechanics is the branch of physics that studies the motion of objects, which studies the laws of motion of objects, as well as the forces acting between them.

It involves the laws of motion of objects, as well as the forces between objects, such as gravity, repulsion, friction, etc.

It also deals with concepts like momentum, kinetic energy, potential energy of an object, etc.

Thermodynamics is the branch of physics that studies the thermal motion of matter, which studies the laws of thermal motion of matter, as well as the thermal interaction between substances.

It involves the laws of thermal motion of matter, as well as the thermal interaction between substances, such as heat conduction, heat convection, thermal expansion, etc.

It also deals with the thermodynamic properties of the substance, such as heat capacity, thermal conductivity, coefficient of thermal expansion, etc.

Electromagnetism is the branch of physics that studies electromagnetic phenomena, which study the laws of electromagnetic phenomena and the role of electromagnetic fields.

It deals with the laws of electromagnetic phenomena and the role of electromagnetic fields, such as electric fields, magnetic fields, electromagnetic waves, etc.

It also deals with the basic concepts of electromagnetism like charge, current, voltage, capacitance, inductance, etc.

Optics is the branch of physics that studies light, and it studies the properties and behavior of light, as well as the interaction between light and objects.

It deals with the properties and behavior of light, as well as the interaction between light and objects like reflection, refraction, diffraction, interference, etc.

It also deals with the basic concepts of optics like the wavelength of light, the frequency of light, the speed of light, etc.

Quantum mechanics is the branch of physics that studies microscopic particles, which studies the properties and behavior of microscopic particles, as well as the interactions between microscopic particles.

It deals with the properties and behavior of microscopic particles, as well as the interactions between microscopic particles, such as quantum splitting, quantum transitions, quantum interference, etc.

It also deals with the basic concepts of Xiaowang quantum mechanics, such as quantum states, quantum transitions, quantum interference, etc.

The categories of classical physics include mechanics, thermodynamics, electromagnetism, optics, quantum mechanics, etc., which are the basis of physics and the study of physical phenomena.

They involve the laws of motion of objects, the laws of thermal motion of matter, the laws of electromagnetic phenomena, the properties and behavior of light, the properties and behavior of microscopic particles, etc., and the relationship between them.

Their research has laid a solid foundation for the development of physics and provided important theoretical guidance for human exploration of the physical world.

There is a Hamiltonian principle in theoretical mechanics called first principles, which is that energy has a tendency to be minimal (strictly speaking, the amount of action), from which the three major conservation rates (momentum, angular momentum, and energy) can be deduced from the basis of which, together with space translation, rotation without deformation and time translation without deformation. These are the foundations of physics no matter what.

In addition, the Galilean transform (mainly the invariant mass) can be deduced Newton's three laws (the bull uniform is actually a special case of the Galilean transformation, and the bull second rate can be deduced from the Galilean transform and the conservation of momentum, and the bull third rate is actually equivalent to the conservation of momentum).

This is the basis of classical mechanics. But to solve some problems, we need to add some empirical formulas such as the law of universal gravitation. But it's not a basic principle anymore.

Classical thermodynamics adds one, but not two, statistical principles (I just remember that there is a phase space principle), and classical electromagnetism adds Maxwell's equations.

Maxwell's equations's equations) is a set of partial differential equations established by the British physicist James Maxwell in the 19th century to describe the relationship between electric and magnetic fields and charge density and current density. It consists of four equations:

Gauss's law, which describes how electric charges produce electric fields, Gauss's laws that describe the non-existence of magnetic monopoles, Maxwell's Ampère's law, which describes how electric currents and time-varying electric fields produce magnetic fields, and Faraday's induction law, which describes how time-varying magnetic fields produce electric fields.

From Maxwell's equations, it can be deduced that electromagnetic waves propagate at the speed of light in a vacuum, and then make the conjecture that light is an electromagnetic wave. Maxwell's equations and Lorentz force equations are the fundamental equations of classical electric magnetism. From the relevant theories of these basic equations, modern power technology and electronic technology have been developed.

<> understanding and views of physics are as follows:

1. Physics is a regular summary of people's knowledge of the transformation of matter in inanimate nature;

2. Physics can be divided into two types: movement and transformation, one is the extension of early people's sensory vision, and the other is the results of experiments obtained by modern people through the invention and creation of scientific instruments for observation and measurement;

3. Physics can be divided into two parts: micro and macroscopic, macroscopic is not to analyze the individual effect of the particle group and directly consider the overall effect, which has appeared in the earliest days, and the theory of microphysics has been gradually improved with the development of science and technology;

4. Physical ideas and methods are not only valuable to physics itself, but also have important contributions to the development of the whole natural science and even social science.

5. The relationship between physics and metaphysics is that on the basis of the objective principles of non-empiricism produced by continuous reflection on metaphysics, physical theories can be judged by their own scientific terms.

Physics is the study of the most general laws of motion of matter and the basic structure of matter. As a leading discipline in the natural sciences, physics studies the most basic forms and laws of motion of all matter, from the universe to elementary particles, and thus becomes the research foundation of other natural science disciplines.

Basic properties: Physics is a regular summary of people's knowledge of the movement and transformation of matter in nature, and there should be two kinds of such movement and transformation. One is the extension of early people's vision through the senses; Second, modern people have indirectly understood the internal composition of matter through the invention and creation of scientific instruments for observation and measurement, and the results obtained from experiments have been established.

Physics can be roughly divided into two parts: macroscopic physics does not analyze the effect of a single action in a particle group and directly considers the overall effect, which has appeared in the earliest days; The birth of microphysics originated from the fact that macroscopic physics could not explain new experimental phenomena such as black-body radiation, photoelectric effect, and atomic spectroscopy.

It is a modification of macroscopic physics and has been gradually refined with the development of experimental technology and theoretical physics.

Secondly, physics is a kind of intelligence.

As the German scientist Born, winner of the Nobel Prize in Physics, put it: "It is because my published work contains the discovery of a natural phenomenon, but because it contains a scientific methodological basis for natural phenomena." ”

The reason why physics is recognized as an important science is not only because it has profoundly revealed the laws of the objective world, but also because it has formed a set of unique and fruitful ideological methods in the process of development and growth. Because of this, physics has deservedly become the crystallization of human intelligence and the treasure of civilization.

A large number of facts show that physical ideas and methods are not only valuable to physics itself, but also have important contributions to the development of the entire natural sciences and even social sciences.

It has been calculated that since the middle of the 20th century, more than half of the winners of the Nobel Prize in Chemistry, Biology and Medicine, and even Economics have a background in physics – meaning that they have taken intelligence from physics and turned to success in non-physical fields.

Conversely, there has never been a case of a scientist with a non-physics background winning the Nobel Prize in Physics. That's the power of physical intelligence. It is no wonder that some foreign experts have pointed out very sharply: A nation without physical cultivation is a stupid nation!

In short, physics is a summary of the generalized laws of the natural world, and a theoretical understanding of empirical science.