What are the types of matter. The concept of matter. Types and properties of matter. Types of motion of matter

Matter "is one of the most fundamental concepts of philosophy. However, in various philosophical systems its content is understood differently. Idealistic philosophy, for example, is characterized by the fact that it either completely rejects the existence of matter or denies its objectivity. Thus, the outstanding ancient Greek philosopher Plato considers matter as a projection of the world of ideas. In itself, matter in Plato is nothing. In order to turn into reality, some idea must be embodied in it.

For the follower of Plato, Aristotle, matter also exists only as a possibility, which turns into reality only as a result of its combination with form. Forms ultimately originate from God.

In G. Hegel, matter manifests itself as a result of the activity of the absolute idea, the absolute spirit. It is the absolute spirit, the idea that gives rise to matter.

Matter - a philosophical category to designate objective reality, cat. given to him in his sensations, which is copied, photographed, displayed, by our sensations, existing independently of them. In this definition, 2 signs of matter are singled out: 1) Recognition of the primacy of matter in relation to consciousness (objectivity of sensation) 2) Recognition of the fundamental cognizability of the world. Lenin distinguishes between the philosophical understanding of matter and natural scientific knowledge about the existing world. Lenin contributed to overcoming the crisis in physics associated with the inclusion of the principle of the structural nature of matter and the divisibility of atoms in the scientific picture of the world.

MATTER (according to Lenin) is a philosophical category for designating objective reality, which is given to a person in his feelings, which is copied, photographed by our feelings, existing independently of them. Matter is the substance of our world. Substance - substrate (a certain basis, carrier) + its St. Islands. If earlier matter was identified with the atom, now the electron has been discovered and matter is relative, nature is infinite.

Matter types : 1) Substance is a type of matter that has a rest mass. Solid, liquid, gaseous, plasma. 2) The field has no rest mass. The form of matter is a set of various material objects and systems that have a single qualitative certainty, manifesting in general properties and specific to a given form of matter, ways of existence. Forms: 1) Social (Ch-to, human society, labor). 2) Biological (wildlife). 3) Chemical (atoms). 4) Physical (lower - atoms, molecules, fields).

In modern science, the method of structural analysis is widely used, which takes into account the systematic nature of the objects under study. After all, structure is an internal dismemberment of material existence, a way of existence of matter. Structural levels Matters are formed from a certain set of objects of some kind and are characterized by a special way of interaction between their constituent elements. In relation to the three main spheres of objective reality, these levels look like this:

The study of the problems associated with the philosophical analysis of matter and its properties is a necessary condition for the formation of a person's worldview, regardless of whether it ultimately turns out to be materialistic or idealistic.

In the light of the foregoing, it is quite obvious that the role of defining the concept of matter, understanding the latter as inexhaustible for building a scientific picture of the world, solving the problem of reality and cognizability of objects and phenomena of the micro- and mega-world is very important.

The following definition is reasonable: "... Matter is an objective reality given to us in sensation"; "Matter is a philosophical category for designating an objective reality that is given to a person in his sensations, which is copied, photographed, displayed by our sensations, existing independently of them." (In the first case, we are talking about matter as a category of being, an ontological category, in the second - about a concept that fixes it, an epistemological category).

The structure of matter

Science widely uses the idea of ​​the structural levels of matter, specifying the forms of motion and types of matter. Structural levels of matter are formed from objects of a certain set and any class. A characteristic feature of these objects is special type interactions between their constituent elements. The following signs can serve as a criterion for distinguishing different structural levels: space-time scales, a set of important properties and laws of change, the degree of relative complexity that arises in the process of the historical development of matter in a given area of ​​the world.

The elements of the structure of matter are:

Inanimate nature;

Nature;

Society (society).

Each element of matter has several levels. The levels of inanimate nature are:

Submicroelementary (tiniest units of matter, smaller than an atom);

Microelementary (hadrons consisting of quarks, electrons);

Nuclear (the nucleus of an atom);

Atomic (atoms);

Molecular (molecules);

The level of single things;

The level of macrobodies;

Planet level;

The level of planetary systems;

Level of galaxies;

The level of galaxy systems;

The level of metagalaxies;

The level of the Universe, the world as a whole.

The levels of wildlife include:

Precellular (DNA, RNA, proteins);

Cellular (cell);

The level of multicellular organisms;

Species level;

population level;

Biocenoses;

The level of the biosphere as a whole.

Social levels include:

separate individual;

Teams of different levels;

Social groups (classes, strata);

Separate societies;

States;

Unions of states;

Humanity as a whole.

In addition, in modern natural science, matter is divided into three types: substance, physical field and physical vacuum. One of the main properties of matter is motion. Without motion, there is no matter, and vice versa. The movement of matter is any changes that occur with material objects as a result of their interactions. types of matter: substance, physical field and physical vacuum. The main type of matter is a substance that has mass. Material objects include elementary particles, atoms, molecules and various material objects formed from them. In chemistry, substances are divided into simple (they consist of an atom of one chemical element) and complex, called chemical compounds. The properties of a substance depend on external conditions and the intensity of the interaction of atoms and molecules. This causes different aggregate states of matter: solid, liquid and gaseous. At a sufficiently high temperature, a plasma is formed. The transition of matter from one state to another can be characterized as one of the types of motion of matter. In nature, there are various types of motion of matter. They can be classified taking into account changes in the properties of material objects and the impact on the surrounding world. Wave and vibrational motion, mechanical motion (relative displacement of bodies), distribution and change of various fields, thermal (chaotic) motion of atoms and molecules, phase transitions between aggregate states (vaporization, melting, etc.), equilibrium and non-equilibrium processes in macrosystems , radioactive decay, nuclear and chemical reactions, the development of living organisms and the biosphere, the evolution of stars, galaxies and the universe as a whole - all this is an example of a variety of different types the motion of matter. A special type of matter, which provides physical interaction of both material objects and their systems, is a physical field. Physical fields include gravitational and electromagnetic fields, the field of nuclear forces, as well as quantum (wave) fields that correspond to different particles (for example, an electron-positron field). Particles serve as a source of physical fields, for example, for an electromagnetic field, these are charged particles. The physical fields created by the particles transfer the interaction between them with a finite speed. In quantum theory, interaction is a consequence of the exchange of field quanta between particles.

It is customary to consider space and time as general universal forms of the existence of the motion of matter. The movement of material objects, as well as various real processes, are carried out in space and time. The peculiarity of the natural-scientific conception of these concepts is that space and time can be characterized quantitatively with the help of instruments. Time is an objective characteristic of any phenomenon or process, it determines the order of change of physical states. Time is all that can be measured with many instruments. The principle of operation of these devices lies in various physical processes, among which periodic processes are considered the most convenient: electromagnetic radiation of excited atoms, the rotation of the Earth around its axis, etc.

Many major advances in natural science are associated with the development of more accurate instruments for determining time. The standards that exist today allow you to measure time with enough high precision, in this case the relative measurement error is no more than 10-11%. The temporal characteristic of real processes is based on the postulate of time: exactly the same phenomena occur in the same time. Despite the fact that the postulate of time seems natural and obvious, its truth is still relative, because it cannot be verified by experience even with the help of the most ideal clock, since, firstly, they are characterized by their accuracy, and, secondly , it is impossible to create exactly the same conditions in nature at different times. At the same time, the rather long practice of natural science research allows us to doubt the validity of the postulate of time within the limits of accuracy achieved at a given moment in time. Creating classical mechanics, I. Newton introduced the concept of absolute (true) mathematical time, flowing always and everywhere uniformly, and relative time, which acts as a measure of duration used in everyday life and meaning a certain interval of time: hour, day, month etc.

In the modern view, time is always relative. It follows from the theory of relativity that at a speed that tends to the speed of light in vacuum, time slows down, that is, relativistic time dilation occurs, and a strong gravitational field leads to gravitational time dilation. Under ordinary terrestrial conditions, these effects are extremely small.

The main property of time is its irreversibility. In real life, it is impossible to reproduce the past again in all its details and details, as it is forgotten. The irreversibility of time is explained by the complex interaction of many natural systems, and is symbolically indicated by the arrow of time, which always seems to fly from the past to the future. The irreversibility of real processes in thermodynamics is associated with the chaotic motion of atoms and molecules. The concept of space is much more complex than the concept of time. Unlike one-dimensional time, real space has three dimensions, that is, it is three-dimensional. In three-dimensional space there are atoms and planetary systems, the fundamental laws of nature are fulfilled. But there are hypotheses according to which the space of the Universe has many dimensions, but of them our senses are able to feel only three.

The very first ideas about space originated from the obvious existence in nature solids that occupy a certain volume. Based on this, we can say that space expresses the order of coexistence of physical bodies. More than 2000 years ago, a complete theory of space was created - the geometry of Euclid, which is still considered a model of scientific theory. By analogy with absolute time, I. Newton introduced the concept of absolute space, which exists independently of the physical objects located in it and, possibly, completely empty. It is, as it were, a world arena where various physical processes take place. The properties of space are expressed by Euclid's geometry. It is this idea of ​​space that forms the basis of the practical activity of people. Although empty space is ideal, while the real world around us is filled with various material objects. Without material objects, ideal space does not make sense even, for example, when describing the mechanical motion of a body, for which you need to take another body that acts as a frame of reference. The mechanical motion of bodies is relative. In nature there is neither absolute rest nor absolute movement of bodies. Space, like time, is relative. The special theory of relativity combined space and time into a single continuum "space-time". The basis for such a union is the postulate of the maximum speed of transmission of interactions of material objects and the principle of relativity. From this theory follows the relativity of the simultaneity of two events that occur at different points in space, and the relativity of measurements of lengths and time intervals that are made in different frames of reference moving relative to each other. According to the general theory of relativity, the properties of "space - time" are subject to material objects. Any thermal object distorts space, which can be described not by Euclid's geometry, but by Riemann's spherical geometry or Lobachevsky's hyperbolic geometry. It is believed that around a massive body with a very high density of matter, the distortion becomes so significant that "space - time" seems to "close" locally on itself, separates this body from the rest of the Universe and forms a black hole that absorbs electromagnetic radiation and material objects. . On the surface of a black hole, for external observation, time seems to stop. It can be assumed that there is a huge black hole in the center of our Galaxy. But there is another point of view. According to the Academician of the Russian Academy of Sciences A. A. Logunov, there is no distortion of space-time, but there is a distortion of the trajectory of the movement of objects, which is due to a change in the gravitational field. He argues that the observed redshift in the emission spectrum of distant galaxies can be explained not by the expansion of the Universe, but by the transition of the radiation they send from a medium with a strong gravitational field to a medium with a weak gravitational field, in which the observer on Earth is located.

Now it should be considered that matter, like other types of matter (physical vacuum and physical field) have a discontinuous structure. Based on quantum field theory, time and space on very small scales form a chaotically changing space-time environment. Quantum cells are extremely small, so they can be ignored when describing the properties of atoms, nucleons, etc., assuming that time and space are continuous.

The main type of matter is a substance that is in a solid or liquid state and is usually perceived as a continuous, continuous medium. To describe and analyze the properties of such a substance, in most cases, only its continuity is taken into account. However, this substance in explaining chemical bonds, thermal phenomena, electromagnetic radiation, etc. is considered as a discrete medium consisting of interacting atoms and molecules. Discreteness and continuity are also inherent in another kind of matter - the physical field. Magnetic, electric, gravitational and other fields in the solution of many physical problems are considered to be continuous. But in quantum field theory, physical fields are considered to be discrete.

For the same types of matter, discreteness and continuity are characteristic. For the properties of material objects and the classical description of natural phenomena, it is sufficient to take into account the continuous properties of matter, and to characterize various microprocesses, its discrete properties. The integral properties of matter are discreteness and continuity. The most important property of matter is its structural and systemic organization, which expresses the orderliness of the existence of matter in the form of a wide variety of material objects of different levels and scales, which are interconnected by a single hierarchy system. The bodies we observe consist of molecules, molecules of atoms, atoms of nuclei and electrons, atomic nuclei of nucleons, nucleons of quarks. Now it should be assumed that electrons and hypothetical quark particles do not contain smaller particles.

From a biological point of view, the largest living system is the biosphere. It consists of biocenoses, which contains many populations of living organisms of different species. Populations form separate individuals, the living organism of which consists of cells with a complex structure, including the nucleus, membrane and other components.

Now many material systems are conventionally divided into the microcosm, the macrocosm and the megaworld. The microworld includes molecules, atoms and elementary particles. Material objects, which consist of a large number of atoms and molecules, form the macrocosm. The largest system of material objects is considered to be the mega world - this is the world of planets, stars, galaxies and the Universe. The material systems of the micro-, macro- and mega-world differ from each other in size, the nature of the prevailing processes and the laws to which they obey.

So, each of the three areas of material reality is formed from a number of special structural levels, which are not in their chaotic "set" as part of some area of ​​reality, but in a certain connection, orderliness. The transition from one area to another is associated with an increase and complication of the variety of factors that ensure the integrity of systems (in inanimate nature - electromagnetic, nuclear and other forces, in society - industrial relations, national, political, etc.). Within each of the structural levels of matter there are relations of subordination: the molecular level includes the atomic level (but not vice versa); organismic - cellular, tissue level of society - levels represented by nations, classes, other social levels. The patterns of new levels are specific, they cannot be reduced to the patterns of the levels on the basis of which they arose, and are leading for this level. structural organization matter. The mode of existence of matter is structural diversity, i.e. systemicity. The initial concept in the representation of matter as a structurally ordered formation is the concept of "system". It can be associated with ideas about the world as a whole (in the stipulated, of course, meaning of this term), forms of the movement of matter, structural levels of the organization of matter, separate integral objects within the structural levels of matter, different levels, aspects, "sections" of these material objects. On this concept, as on the initial one, the whole picture of the universal structuredness of matter is based.

Lecture topic: Physics of matter.
definition
Matter is a tangible and intangible content existing in space,

filling (occupying) a place in space, possessing physical properties.
Simply put, matter is everything that exists (is present) in space, regardless of its own nature, including tangible and intangible. All this is matter.

What should be understood in this regard:
It is necessary to clearly understand what is matter and what is not matter.
Not everything that people have an idea about is matter.
Matter is not space itself, but only what is located in it.

This is the first important position to understand.
The second important point to understand is that
matter is not information and abstractions.
And in relation to information, only the carrier of information, and not the information itself, can be material.
That is, matter is separate, space is separate, and information is separate, all fantasies, images, thought forms and glitches are all separate. They are not matter.
We will not be able to break grandmother's TV with dumbbells in a dream of grandfather.

Based on the definition of matter as “a content that exists in space and has properties”), we can easily distinguish the material from the non-material, for example, how does a real material (existing in reality) penguin differ from an imaginary non-material (non-existing in reality).

A real penguin has physical properties, fills a place in space and has an extension. An imaginary penguin, on the contrary, has no real properties, does not fill a place in space and is present not in space, but in the imagination of an individual, and only in a virtual form, for example, in the form of a certain image.
The location of the imaginary penguin is not the real world, not space, but an abstract "world" - imagination.
And such a penguin straightens its shoulders not in space, but in the imagination of the individual.
And we will not be able to detect in the human brain either imagination itself, or that puddle where an imaginary penguin is splashing.
If we wish, we can try to designate in space the dimensions of an imaginary penguin, but we cannot fill the chosen place with an imaginary penguin.
An imaginary penguin has no non-fictional properties.
An imaginary penguin will not bake in the oven, and we will not even be able to prepare such a penguin for the winter, let alone take it away from Obama.

We can't douse an imaginary penguin with paint or throw eggs at it. Paint will not stick to him, and he can easily dodge eggs .

That is, the presence or absence physical properties- a person can distinguish the imaginary from the real.
Further
Real physical matter exhibits various properties, and we can divide matter into categories in accordance with common features.
According to the properties of discontinuity-continuity (in other words, discreteness), matter is divided into discrete and non-discrete forms

Non-discrete (continuous) matter in nature is represented as a field
Discrete (discontinuous, granular) matter in nature is represented in the form of particles.
Particles, in turn, are in one of two states:
- either behave directly as particles move in space at a speed close to the speed of light
- or grouped into a substance.
That is, in more detail on the basis of grouping - you can divide the matter in more detail and distinguish three main categories.
Substance, particles, field.

The first position is the particles grouped into a substance,
Second position - free particles (not grouped into matter)
and third position field.
And matter in nature manifests itself both as substance and as particles and as a field.
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And again, it should be well remembered that matter is only that which has properties.
The unknown “chavoit” that does not have properties is not matter.
If some matter exists but has not yet been discovered,
then, upon detection, according to its properties, it will fall into one of the categories
either matter, or free particles, or field.
let's look at the points.
What is a substance.
Matter is a type of matter that has a rest mass.
Anything that has rest mass is matter. Water (liquid) is a substance. Gas is a substance.
And all objects in our tangible world are made of matter, it doesn't matter if it's slate or grandmother's airship - all this ultimately consists of particles and all this stuff.

With the realization that such a substance usually does not arise difficulties and, as a rule, everyone is able to understand what a substance is.
Further.
position - field.
The field is something material, but immaterial. And not everyone is immediately able to comprehend (realize, understand) how the material can be insubstantial.
In fact, everything is quite simple.
Scientists initially decided what to consider material
Material is everything that is in space and has properties.
Here we have 100% of what is in space - this is matter
and part of it exhibits such and such properties.

If there were no properties, it would not be matter.
Shows properties - so this is one of the forms of matter,
At the same time, according to the actual manifestations, the field does not correspond to the definition of matter, in particular, the field has no mass.
And collectively it turns out that in terms of its properties the field is material but not material.
To understand what a field is, one must imagine physics without a field.
Two bricks fly towards each other.
How do two bricks touch?
Atoms touch along the outer contour.
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Let's look at how the atoms interact there and how it will look without a field:
Two atoms fly towards each other,
protons set up, electrons fluffed up, now a big boom will happen

But the atoms did not take the field with them, there was nothing to catch on to each other, so they slipped through.

These atoms did not notice any collision, could not notice.
What is the total volume of discrete objects that make up an atom?
How much meat is there in this atom? How much is there that you can feel and how much does it take up? Sometimes atoms are drawn very meaty. Sometimes not so much.

But if we consider in more detail, then there is a distance between the particles, and each smaller element, in turn, is again planetary, which means that discrete matter again occupies an insignificant part of the total volume. And it all tends to almost zero.

That is, it is not necessary to depict a fleshy atom, but a skinny one.

Let's simulate an atom without a field.
And to make it clear, let's take half a squadron of ordinary-sized flies and let them fly over the Moscow ring road, right above the cars in a large circle.

And in the center, in the area of ​​​​the Arbat, let the main such proton fly jump, and let the rest of the flies around it, the main one, fly around the ring without approaching.
We got a quite decent fly model of an atom without fields.
And now let's place the second similar fly model of the atom somewhere in Lapland and start bringing both of these models closer to each other.
Let them, like adults, fly at each other.
What is the probability that when the models of these two atoms approach each other, they will catch on to each other?
And what are they hooked on?
There is a lot of buzzing, but there is no field at all.
Even if some two flies hit each other exactly in the forehead, then in this case they will not be able to catch on. The second atom is also a planetary system, practically emptiness.
No chance of hooking. There is nothing to cling to without a field.
Two atoms under such conditions freely fly through each other.
With such a geometry without a field, this is one continuous draft.
In principle, we would not be able to collide any two elementary particles if they did not have a field.
Bricks would fly through each other remarkably.
That's actually what role the field plays.
Without a field, in principle, we have no possibility of interaction either at the macro or at the micro level.
Go ahead:
What are the field properties?
The field has neither internal nor external discreteness.
That is, it has no gaps, and also has no external boundaries as such.

You can understand the geometry of the field from the graph of the distribution of the impact on the expanding sphere:

The graph tends to zero but does not reset. No matter how far we are from the source of the field
The field is weakening but will not disappear. The field itself has no borders.
In addition, the field is elastic.
(Magnet)
The field is fundamentally elastic, non-discrete and has no mass.
Field definition:
A field is a special kind of matter that does not have mass, it is a continuous object located in space, at each point of which a particle is affected by balanced or unbalanced forces of certain magnitude and direction.
And again, we do not forget that this is a long-known information
and within the framework of the physical concept, matter and field are traditionally opposed to each other as two types of matter, the first of which has a discrete structure, while the second is continuous.

Let's delve into the materiel:
The first thing to understand is that the entire universe at the macro level is uniformly filled with material matter, which means that it is uniformly filled with a field.

In terms of force, this is the most powerful of the existing physical phenomena and it has a gravitational nature. The total gravitational field.
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All physical interactions, including every bond in every atom in your body, is determined by this field.
The gravitational field is fundamental, and all other fields are particular local phenomena on this basic gravitational field.
Imagine if there were billions of rubber bands and we cut just one. And this would be an analogue of the secondary field, such as the electromagnetic field.
Partial perturbation on the base field.
And when we consider the field of any magnet, this is also a secondary field - an insignificant perturbation on the basic gravitational field that has a colossal potential.
In a certain sense, the gravitational field is the same ether or, in other words, the “physical vacuum” that everyone is looking for and cannot find. But it is a single non-discrete non-corpuscular object.
Forces arise at every point in the space filled with a field and there are no gaps there.

The next position of the particle.
A particle is a material discrete micro-object.
What are the main differences between particles and field.
The particles are discrete (each of them represents an independent object of a complex internal structure),
In this they differ from the field, which non-discretely has no internal discreteness (has no discontinuities), as well as the field, which has no external boundaries as such.

With regard to particles, it should be understood that the division of matter into categories that is common in science is not entirely strict.
In the literature, sometimes non-strict incorrect interpretations are allowed.

Free particles that have mass according to the modern scientific fashion are classified as an independent category, and particles that do not have rest mass are in some cases loosely treated as a field.
And in this place for many there comes a misunderstanding known as corpuscular wave dualism.
We have already explained the reasons for this mental phenomenon separately (in the section on corpuscular-wave dualism). We will not stop again.
At this point, it suffices to recall that in the scientific sense, both particles and field and wave are still independent concepts.
And this is the requirement of the first law of logic, which states:
“...to have more than one meaning means not to have a single meaning; if words have no meaning, then all possibility of reasoning with each other, and in fact with oneself, is lost; for it is impossible to think of anything if one does not think of one thing.
Either a field or a particle.

Brick is matter, brick consists of that part of matter which is commonly called substance
But that's not all.
There is a bunch of matter (and hence any brick) with the field. Each brick is in the total universal field.

And besides, each brick has its own field.
To put it simply, we can call this field the brick field, we can call the brick gravitational field.

There is not a single brick in nature that is not surrounded by its own field.
a field accompanies each brick.
All material matter in nature has a field.
And in this regard, it is necessary to understand that in nature there is no substance that does not have its own private field.
And any material object in the fundamental physical sense is a combination of matter and field.
And this field is distributed evenly in all directions from the substance, and as you move away from the substance, this field weakens.

That is, fundamentally, each object with mass has its own field, and in addition, all the masses of the universe together form a single gravitational field of the universe.
Now let's understand: where is the brick, and where is its private field. The private field is tied to a brick.
If we divide the brick into parts and separate these parts to the sides, then the private field of the brick will also be divided and spaced apart.
(breaking a brick)
The private brick field is divided and spaced apart.

Now let's look at what is common between particles bound within a substance and between unbound, free particles.
Example.
What will the systematic splitting of bricks lead to, the division of bricks
Systematic destruction of the so-called internal bonds of a brick.
Without exception, all internal connections of a brick are determined from the outside, from the side of the base field. The total universal field creates a colossal tension in space, which determines all internal connections in material objects.
The deeper we split the brick, the smaller the fraction, the more particles will become unbound substance, these particles will separate from the brick and begin to move at a speed close to the speed of light.
If the splitting is continued, then all the fragments will be split, released to the level of unbound particles and, under the influence of an external field, will begin to move at a speed close to the speed of light in all free directions.
That is, if a brick is completely split, to the level of particles, then the brick will rush off at the speed of light in all free directions.
And if there were no external field at all, then the brick would do the same, but at a much higher speed, at a speed exceeding the speed of light (but this is a subject of a separate discussion, as well as issues of mass and the so-called neutrino).
For a general understanding, let's consider what the situation would be for a universe not filled with matter.
Empty universe and one brick.
It would seem, but how do we know?
But in fact, we know this absolutely for sure, because there are only two options for applying forces to a body: attraction and repulsion.
And we also know that matter cannot exist on the forces of direct attraction in principle, it is technically impossible, because it inevitably leads to an avalanche-like process of collapse in matter at one point.
Those who do not know this yet can watch the evidence part at the link, or watch the film "Equilibrium in Physics".
Let's continue:
The only possible option for the existence of matter in space is mutual repulsion, which, if the universe is sufficiently saturated with matter, leads to a complex repulsion of masses to each other.
Gravity is a complex repulsion.
So what will happen to a brick in a universe not filled with matter?
(Totally empty universe and one brick).
In such a scenario, there is, in principle, nothing to ensure the internal connections of a brick. There is no external field, external forces, external repulsion. The entire substance of the brick without options will completely split and scatter in all directions, and the field of the brick will also dissipate accordingly.
No existence of any material physical body under such conditions is possible.
In a universe filled with bodies, masses, the picture is different.
The masses "created" a common field,
at the macro level, the universe was filled evenly, a carpet of galaxies.
This field provided internal bonds in each brick.
And we see that in the real universe, matter does not disintegrate into particles and does not scatter.

Actually everything.

Matter: matter, particles, field.
And if there were no field, then there would be no interactions between particles, and the particles themselves, in the usual sense, would not exist either.
Viktor Katyushchik was with you.
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Matter- an infinite set of all objects and systems coexisting in the world, the totality of their properties and connections, relations and forms of movement. It includes not only directly observed objects and bodies of nature, but also all those that are not given to man in his sensations.

Movement is an essential property of matter. The motion of matter is any change that occurs with material objects as a result of their interactions. In nature, various types of motion of matter are observed: mechanical, oscillatory and wave, thermal motion of atoms and molecules, equilibrium and non-equilibrium processes, radioactive decay, chemical and nuclear reactions, the development of living organisms and the biosphere.

At the present stage of development of natural science, researchers distinguish the following types of matter: matter, physical field and physical vacuum.

Substance is the main type of matter that has a rest mass. Material objects include: elementary particles, atoms, molecules and numerous material objects formed from them. The properties of a substance depend on external conditions and the intensity of the interaction of atoms and molecules, which determines the various aggregate states of substances.

physical field is a special kind of matter that provides the physical interaction of material objects and their systems. Researchers refer to physical fields: electromagnetic and gravitational fields, the field of nuclear forces, wave fields corresponding to various particles. Particles are the source of physical fields.

physical vacuum is the lowest energy state of the quantum field. This term was introduced into quantum field theory to explain certain processes. The average number of particles - field quanta - in vacuum is equal to zero, but particles in intermediate states that exist for a short time can be born in it.

When describing material systems, corpuscular (from lat. corpusculum- particle) and continual (from lat. continuous- continuous) theory. Continuum the theory considers repetitive continuous processes, fluctuations that occur in the vicinity of a certain average position. When vibrations propagate in a medium, waves arise. The theory of oscillations is a branch of physics that studies these regularities. Thus, the continuum theory describes wave processes. Along with the wave (continuum) description, the concept of a particle - corpuscles is widely used. From point of view continuous concept, all matter was considered as a form of a field uniformly distributed in space, and after a random perturbation of the field, waves arose, that is, particles with different properties. The interaction of these formations led to the appearance of atoms, molecules, macrobodies, forming the macroworld. On the basis of this criterion, the following levels of matter are distinguished: microcosm, macrocosm and megaworld.

The microworld is a region of extremely small, directly unobservable material micro-objects, the size of which is calculated in the range from 10 -8 to 10 -16 cm, and the lifetime - from infinity to 10 -24 s. This is the world from atoms to elementary particles. All of them have both wave and corpuscular properties.

Macroworld- the world of material objects, commensurate in scale with a person. At this level, spatial quantities are measured from millimeters to kilometers, and time from seconds to years. The macrocosm is represented by macromolecules, substances in various states of aggregation, living organisms, man and the products of his activity.

Megaworld- a sphere of huge cosmic scales and velocities, the distance in which is measured in astronomical units (1 AU \u003d 8.3 light minutes), light years (1 light year \u003d 10 trillion km) and parsecs (1pc \u003d 30 trillion km), and time of existence of space objects - millions and billions of years. This level includes the largest material objects: planets and their systems, stars, galaxies and their clusters forming metagalaxies.

Classification of elementary particles

Elementary particles are the main structural elements of the microworld. Elementary particles can be constituent(proton, neutron) and non-composite(electron, neutrino, photon). To date, more than 400 particles and their antiparticles have been discovered. Some elementary particles have unusual properties. Thus, for a long time it was believed that the neutrino particle has no rest mass. In the 30s. 20th century when studying beta decay, it was found that the energy distribution of electrons emitted by radioactive nuclei occurs continuously. It followed from this that either the law of conservation of energy is not fulfilled, or, in addition to electrons, difficult-to-detect particles are emitted, similar to photons with zero rest mass, which carry away part of the energy. Scientists have suggested that this is a neutrino. However, experimental registration of neutrinos was possible only in 1956 at huge underground installations. The difficulty of registering these particles lies in the fact that the capture of neutrino particles is extremely rare due to their high penetrating power. During the experiments, it was found that the rest mass of the neutrino is not equal to zero, although it does not differ much from zero. Antiparticles also have interesting properties. They have many of the same features as their twin particles (mass, spin, lifetime, etc.), but differ from them in terms of electric charge or other characteristics.

In 1928, P. Dirac predicted the existence of an antiparticle of the electron - the positron, which was discovered four years later by K. Anderson as part of cosmic rays. An electron and a positron are not the only pair of twin particles; all elementary particles, except for neutral ones, have their own antiparticles. When a particle and an antiparticle collide, they annihilate (from lat. annihilatio- transformation into nothing) - the transformation of elementary particles and antiparticles into other particles, the number and type of which are determined by conservation laws. For example, as a result of the annihilation of an electron-positron pair, photons are born. The number of detected elementary particles increases with time. At the same time, the search for fundamental particles continues, which could be composite "building blocks" for building known particles. The hypothesis of the existence of such particles, called quarks, was put forward in 1964 by the American physicist M. Gell-Man ( Nobel Prize 1969).

Elementary particles have a large number of characteristics. One of the distinguishing features of quarks is that they have fractional electric charges. Quarks can combine with each other in pairs and triplets. The union of three quarks forms baryons(protons and neutrons). Quarks were not observed in the free state. However, the quark model made it possible to determine the quantum numbers of many elementary particles.

Elementary particles are classified according to the following features: particle mass, electric charge, type of physical interaction in which elementary particles participate, particle lifetime, spin, etc.

Depending on the rest mass of the particle (its rest mass, which is determined in relation to the rest mass of the electron, which is considered the lightest of all particles having mass), they distinguish:

♦ photons (gr. photos- particles that have no rest mass and move at the speed of light);

♦ leptons (gr. leptos- light) - light particles (electron and neutrino);

♦ mesons (gr. mesos- medium) - medium particles with a mass from one to a thousand masses of an electron (pi-meson, ka-meson, etc.);

♦ baryons (gr. barys- heavy) - heavy particles with a mass of more than a thousand masses of an electron (protons, neutrons, etc.).

Depending on the electric charge, there are:

♦ particles with a negative charge (for example, electrons);

♦ particles with a positive charge (eg proton, positrons);

♦ particles with zero charge (for example, neutrinos).

There are particles with a fractional charge - quarks. Taking into account the type of fundamental interaction in which particles participate, among them are:

♦ hadrons (gr. adros- large, strong), participating in electromagnetic, strong and weak interaction;

♦ leptons participating only in electromagnetic and weak interactions;

♦ particles - carriers of interactions (photons - carriers of electromagnetic interaction; gravitons - carriers of gravitational interaction; gluons - carriers of strong interaction; intermediate vector bosons - carriers of weak interaction).

According to the lifetime of the particles are divided into stable, quasi-stable and unstable. Most elementary particles are unstable, their lifetime is 10 -10 -10 -24 s. Stable particles do not decay for a long time. They can exist from infinity to 10 -10 s. The photon, neutrino, proton and electron are considered stable particles. Quasi-stable particles decay as a result of electromagnetic and weak interaction, otherwise they are called resonances. Their lifetime is 10 -24 -10 -26 s.

2.2. Fundamental Interactions

Interaction is the main reason for the movement of matter, therefore interaction is inherent in all material objects, regardless of their natural origin and systemic organization. Features of various interactions determine the conditions of existence and the specifics of the properties of material objects. In total, four types of interaction are known: gravitational, electromagnetic, strong and weak.

gravitational interaction was the first of the known fundamental interactions to become the subject of research by scientists. It manifests itself in the mutual attraction of any material objects that have mass, is transmitted through the gravitational field and is determined by the law of universal gravitation, which was formulated by I. Newton

The law of universal gravitation describes the fall of material bodies in the field of the Earth, the movement of the planets of the solar system, stars, etc. As the mass of matter increases, gravitational interactions increase. Gravitational interaction is the weakest of all known modern science interactions. Nevertheless, gravitational interactions determine the structure of the entire Universe: the formation of all cosmic systems; existence of planets, stars and galaxies. The important role of gravitational interaction is determined by its universality: all bodies, particles and fields participate in it.

The carriers of gravitational interaction are gravitons - gravitational field quanta.

electromagnetic the interaction is also universal and exists between any bodies in the micro, macro and mega worlds. Electromagnetic interaction is due to electric charges and is transmitted using electric and magnetic fields. An electric field occurs when there is electric charges, and magnetic - when electric charges move. Electromagnetic interaction is described by: Coulomb's law, Ampère's law, etc. and in a generalized form - Maxwell's electromagnetic theory, which relates electric and magnetic fields. Due to the electromagnetic interaction, atoms, molecules arise and chemical reactions occur. Chemical reactions are a manifestation of electromagnetic interactions and are the results of the redistribution of bonds between atoms in molecules, as well as the number and composition of atoms in the molecules of different substances. Various aggregate states of matter, elastic forces, friction, etc. are determined by electromagnetic interaction. The carriers of the electromagnetic interaction are photons - quanta of the electromagnetic field with zero rest mass.

Inside the atomic nucleus, strong and weak interactions are manifested. strong interaction ensures the connection of nucleons in the nucleus. This interaction is determined by nuclear forces, which have charge independence, short range, saturation, and other properties. The strong force keeps nucleons (protons and neutrons) in the nucleus and quarks inside nucleons and is responsible for the stability of atomic nuclei. Using the strong force, scientists have explained why the protons of the nucleus of an atom do not fly apart under the influence of electromagnetic repulsive forces. The strong force is transmitted by gluons, particles that “stick together” quarks, which are part of protons, neutrons, and other particles.

Weak interaction also operates only in the microcosm. All elementary particles, except for the photon, participate in this interaction. It causes most of the decays of elementary particles, so its discovery occurred after the discovery of radioactivity. The first theory of the weak interaction was created in 1934 by E. Fermi and developed in the 1950s. M. Gell-Man, R. Feynman and other scientists. The carriers of weak interaction are considered to be particles with a mass 100 times greater than the mass of protons - intermediate vector bosons.

Characteristics of fundamental interactions are presented in Table. 2.1.

Table 2.1

Characteristics of fundamental interactions

The table shows that the gravitational interaction is much weaker than other interactions. Its range is unlimited. It does not play a significant role in microprocesses and at the same time is the main one for objects with large masses. The electromagnetic interaction is stronger than the gravitational one, although the radius of its action is also unlimited. The strong and weak interactions have a very limited range.

One of the most important tasks of modern natural science is the creation of a unified theory of fundamental interactions that unites various types of interaction. The creation of such a theory would also mean the construction of a unified theory of elementary particles.

2.3. Thermal radiation. The birth of quantum concepts

At the end of the XX century. wave theory could not explain and describe thermal radiation in the entire frequency range of electromagnetic waves in the thermal range. And the fact that thermal radiation, and in particular light, are electromagnetic waves, has become scientific fact. The German physicist Max Planck managed to give an accurate description of thermal radiation.

On December 14, 1900, Planck made a report at a meeting of the German Physical Society, in which he outlined his hypothesis of the quantum nature of thermal radiation and a new formula for radiation (Planck's formula). Physicists consider this day the birthday of a new physics - quantum. The outstanding French mathematician and physicist A. Poincaré wrote: "Planck's quantum theory is, without any doubt, the biggest and most profound revolution that natural philosophy has undergone since the time of Newton."

Planck established that thermal radiation (an electromagnetic wave) is emitted not in a continuous stream, but in portions (quanta). The energy of each quantum is

that is, proportional to the frequency of the electromagnetic wave - v. Here h- Planck's constant, equal to 6.62 10 -34 J s.

The agreement between Planck's calculations and experimental data was complete. In 1919, M. Planck was awarded the Nobel Prize.

Based on quantum concepts, A. Einstein in 1905 developed the theory of the photoelectric effect (Nobel Prize in 1922), putting science before the fact: light has both wave and corpuscular properties, it is emitted, propagated and absorbed by quanta (portions). Light quanta were called photons.

2.4. De Broglie's hypothesis about wave-particle duality of particle properties

The French scientist Louis de Broglie (1892-1987) in 1924 in his doctoral dissertation "Studies in the theory of quantum" put forward a bold hypothesis about the universality of wave-particle duality, arguing that since light behaves like a wave in some cases, and in others - as a particle, then material particles (electrons, etc.) due to the general nature of the laws of nature must have wave properties. “In optics,” he wrote, “for a century, the corpuscular method of consideration was too neglected in comparison with the wave method; Was the reverse error made in the theory of matter? Haven't we thought too much about the picture of "particles" and neglected the excessive picture of waves? At the time, de Broglie's hypothesis looked crazy. Only in 1927, three years later, science experienced a huge shock: the physicists K. Davisson and L. Germer experimentally confirmed de Broglie's hypothesis, having obtained a diffraction pattern of electrons.

According to the quantum theory of light by A. Einstein, the wave characteristics of photons of light (oscillation frequency v and wavelength l \u003d c / v) are associated with corpuscular characteristics (energy ε f, relativistic mass m f and momentum p f) by the relations:

According to de Broglie's idea, any microparticle, including those with a rest mass w 0 C 0, must have not only corpuscular, but also wave properties. Corresponding frequency v and the wavelength l are determined in this case by relations similar to those of Einstein:

Hence the de Broglie wavelength -

Thus, Einstein's relations, obtained by him in the construction of the theory of photons as a result of the hypothesis put forward by de Broglie, acquired a universal character and became equally applicable both to the analysis of the corpuscular properties of light and to the study of the wave properties of all microparticles.

2.5. Rutherford's experiments. Rutherford model of the atom

A. Rutherford's experiments

In 1911, Rutherford conducted experiments of exceptional significance that proved the existence of the atomic nucleus. To study the atom, Rutherford used its probing (bombardment) with the help of α-particles, which arise during the decay of radium, polonium and some other elements. Rutherford and his collaborators, even in earlier experiments in 1909, found that α-particles have a positive charge equal in modulus to twice the electron charge q =+2e, and a mass coinciding with the mass of a helium atom, i.e.

m a\u003d 6.62 10 -27 kg,

which is about 7300 times the mass of an electron. Later it was found that α-particles are the nuclei of helium atoms. With these particles, Rutherford bombarded the atoms of heavy elements. Electrons due to their small mass cannot change the trajectory of the α-particle. Their scattering (changing the direction of movement) can only be caused by the positively charged part of the atom. Thus, from the scattering of α-particles, one can determine the nature of the distribution of the positive charge, and hence the mass inside the atom.

It was known that α-particles emitted by polonium fly at a speed of 1.6-107 m/s. The polonium was placed inside a lead case, along which a narrow channel was drilled. The α-particle beam, having passed through the channel and the aperture, was incident on the foil. Gold foil can be made extremely thin - 4-10 -7 m thick (400 gold atoms; this number can be estimated by knowing the mass, density and molar mass of gold). After the foil, the α-particles hit a semitransparent screen coated with zinc sulfide. The collision of each particle with the screen was accompanied by a flash of light (scintillation) due to fluorescence, which was observed under a microscope.

With a good vacuum inside the device (so that there was no scattering of particles from air molecules), in the absence of foil, a bright circle appeared on the screen from scintillations caused by a thin beam of α-particles. When a foil was placed in the path of the beam, the vast majority of α-particles still did not deviate from their original direction, that is, they passed through the foil as if it were empty space. However, there were alpha particles that changed their path and even bounced back.

Marsden and Geiger, Rutherford's students and collaborators, counted more than a million scintillations and determined that about one in 2,000 α-particles deflected through angles greater than 90°, and one in 8,000 through 180°. It was impossible to explain this result on the basis of other models of the atom, in particular Thomson.

Calculations show that when distributed throughout the atom, a positive charge (even without taking into account electrons) cannot create a sufficiently intense electric field capable of throwing an α-particle back. The electric field strength of a uniformly charged ball is maximum on the surface of the ball and decreases to zero as it approaches the center. Scattering of α-particles at large angles occurs as if the entire positive charge of the atom was concentrated in its nucleus - a region that occupies a very small volume compared to the entire volume of the atom.

The probability of α-particles hitting the nucleus and deflecting them through large angles is very small, so for the majority of α-particles the foil did not seem to exist.

Rutherford theoretically considered the problem of the scattering of α-particles in the Coulomb electric field of a nucleus and obtained a formula that makes it possible to determine the number N elementary positive charges +e contained in the nucleus of atoms of a given scattering foil. Experiments have shown that the number N equal to the ordinal number of the element in the periodic system of D. I. Mendeleev, that is N=Z(for gold Z= 79).

Thus, Rutherford's hypothesis about the concentration of a positive charge in the nucleus of an atom made it possible to establish the physical meaning of the ordinal number of an element in the periodic system of elements. The neutral atom must also contain Z electrons. It is essential that the number of electrons in an atom, determined by various methods, coincided with the number of elementary positive charges in the nucleus. This served as a test of the validity of the nuclear model of the atom.

B. Rutherford's nuclear model of the atom

Summarizing the results of experiments on the scattering of α-particles by gold foil, Rutherford established:

♦ atoms by their nature are largely transparent to α-particles;

♦ deviations of α-particles at large angles are possible only if there is a very strong electric field inside the atom, created by a positive charge associated with a large mass concentrated in a very small volume.

To explain these experiments, Rutherford proposed a nuclear model of the atom: in the atomic nucleus (regions with linear dimensions of 10 -15 -10 -14 m) all of its positive charge and almost the entire mass of the atom (99.9%) are concentrated. Around the nucleus in a region with linear dimensions of ~10 -10 m (the dimensions of the atom are estimated in the molecular-kinetic theory), negatively charged electrons move in closed orbits, the mass of which is only 0.1% of the mass of the nucleus. Consequently, the electrons are located at a distance from the nucleus from 10,000 to 100,000 diameters of the nucleus, that is, the main part of the atom is empty space.

Rutherford's nuclear model of atoms resembles the solar system: in the center of the system is the "sun" - the nucleus, and "planets" - electrons - orbit around it, therefore this model is called planetary. The electrons do not fall on the nucleus because the electrical forces of attraction between the nucleus and the electrons are balanced by the centrifugal forces due to the rotation of the electrons around the nucleus.

In 1914, three years after the creation of the planetary model of the atom, Rutherford investigated the positive charges in the nucleus. By bombarding hydrogen atoms with electrons, he found that neutral atoms turned into positively charged particles. Since the hydrogen atom has one electron, Rutherford decided that the nucleus of an atom is a particle carrying an elementary positive charge +e. He called this particle proton.

The planetary model is in good agreement with experiments on the scattering of α-particles, but it cannot explain the stability of the atom. Consider, for example, a model of a hydrogen atom containing a proton nucleus and one electron that moves at a speed v around the nucleus in a circular orbit of radius r. The electron must spiral into the nucleus, and the frequency of its revolution around the nucleus (hence, the frequency of electromagnetic waves emitted by it) must continuously change, that is, the atom is unstable, and its electromagnetic radiation must have a continuous spectrum.

In fact, it turns out that:

a) the atom is stable;

b) an atom radiates energy only under certain conditions;

c) the radiation of an atom has a line spectrum determined by its structure.

Thus, the application of classical electrodynamics to the planetary model of the atom led to a complete contradiction with the experimental facts. Overcoming the difficulties that arose required the creation of a qualitatively new quantum- Theories of the atom. However, despite its inconsistency, the planetary model is still accepted as an approximate and simplified picture of the atom.

2.6. Bohr's theory for the hydrogen atom. Bohr's postulates

The Danish physicist Niels Bohr (1885-1962) in 1913 created the first quantum theory of the atom, linking into a single whole the empirical regularities of the line spectra of hydrogen, Rutherford's nuclear model of the atom, and the quantum nature of the emission and absorption of light.

Bohr based his theory on three postulates, about which the American physicist L. Cooper remarked: “Of course, it was somewhat presumptuous to put forward proposals that contradicted Maxwell’s electrodynamics and Newton’s mechanics, but Bohr was young.”

First postulate(postulate of stationary states): in an atom, electrons can move only along certain, so-called allowed, or stationary, circular orbits, in which, despite their acceleration, they do not radiate electromagnetic waves (therefore, these orbits are called stationary). An electron in each stationary orbit has a certain energy E n .

Second postulate(frequency rule): an atom emits or absorbs a quantum of electromagnetic energy when an electron moves from one stationary orbit to another:

hv \u003d E 1 - E 2,

where E 1 and E 2 are the electron energy before and after the transition, respectively.

When E 1 > E 2, a quantum is emitted (the transition of an atom from one state with a higher energy to a state with a lower energy, that is, the transition of an electron from any farthest to any orbit closest to the nucleus); at E 1< E 2 - поглощение кванта (переход атома в состояние с большей энергией, то есть переход электрона на более удаленную от ядра орбиту).

Convinced that Planck's constant must play a fundamental role in the theory of the atom, Bohr introduced third postulate(quantization rule): in stationary orbits the angular momentum of the electron L n = m e u n r n is a multiple of = h/(2π), i.e.

m e υ n r n = nh, n = 1, 2, 3, …,

where \u003d 1.05 10 -34 J s - Planck's constant (the value h / (2π)) occurs so often that a special designation has been introduced for it (“ash” with a line; in this work, “ash” is direct); m e = 9.1 10 -31 kg - electron mass; r P- radius n-th stationary orbits; υ n is the speed of the electron in this orbit.

2.7. Hydrogen atom in quantum mechanics

The equation of motion of a microparticle in various force fields is the wave Schrödinger equation.

For stationary states, the Schrödinger equation will be:

where Δ is the Laplace operator

, m is the mass of the particle, h is Planck's constant, E- total energy, U- potential energy.

The Schrödinger equation is a second-order differential equation and has a solution that indicates that the total energy in the hydrogen atom must be discrete:

E 1 , E 2 , E 3…

This energy is at the appropriate levels n\u003d 1,2,3, ... according to the formula:

The lowest level E corresponds to the minimum possible energy. This level is called the main level, all the rest are excited.

As the principal quantum number increases n the energy levels are closer together, the total energy decreases, and when n= ∞ it is equal to zero. At E>0 the electron becomes free, unbound to a specific nucleus, and the atom becomes ionized.

A complete description of the state of an electron in an atom, in addition to energy, is associated with four characteristics, which are called quantum numbers. These include: the principal quantum number P, orbital quantum number l, magnetic quantum number m 1 , magnetic spin quantum number m s .

The wave φ-function, which describes the motion of an electron in an atom, is not a one-dimensional, but a spatial wave, corresponding to three degrees of freedom of an electron in space, that is, the wave function in space is characterized by three systems. Each of them has its own quantum numbers: n, l, m l .

Each microparticle, including an electron, also has its own internal complex motion. This movement can be characterized by the fourth quantum number m s . Let's talk about this in more detail.

A. The main quantum number n, according to the formula, determines the energy levels of an electron in an atom and can take on the values P= 1, 2, 3…

B. Orbital quantum number /. It follows from the solution of the Schrödinger equation that the angular momentum of an electron (its mechanical orbital momentum) is quantized, that is, it takes on discrete values ​​determined by the formula

where L l is the angular momentum of an electron in orbit, l- orbital quantum number, which for a given P takes on the value i= 0, 1, 2… (n- 1) and determines the angular momentum of an electron in an atom.

b. Magnetic quantum number m l. It also follows from the solution of the Schrödinger equation that the vector l l(momentum of an electron) is oriented in space under the influence of an external magnetic field. In this case, the vector will unfold in such a way that its projection onto the direction of the external magnetic field will be

Llz= hm l

where m l called magnetic quantum number, which can take the values m l= 0, ±1, ±2, ±1, that is, there are (2l + 1) values ​​in total.

Given the above, we can conclude that a hydrogen atom can have the same energy value, being in several different states (n is the same, and l and m l- different).

When an electron moves in an atom, the electron noticeably exhibits wave properties. Therefore, quantum electronics generally refuses classical ideas about electron orbits. We are talking about determining the probable location of the electron in orbit, that is, the location of the electron can be represented by a conditional "cloud". The electron during its movement is as if "smeared" over the entire volume of this "cloud". quantum numbers n and l characterize the size and shape of the electron "cloud", and the quantum number m l- the orientation of this "cloud" in space.

In 1925 American physicists Uhlenbeck and Goudsmit proved that the electron also has its own angular momentum (spin), although we do not consider the electron to be a complex microparticle. Later it turned out that protons, neutrons, photons and other elementary particles have spin.

Experiences Stern, Gerlach and other physicists led to the need to characterize the electron (and microparticles in general) by an additional internal degree of freedom. Hence, for a complete description of the state of an electron in an atom, it is necessary to set four quantum numbers: the main thing is P, orbital - l, magnetic - m l, magnetic spin number - m s .

V quantum physics it has been established that the so-called symmetry or asymmetry of the wave functions is determined by the spin of the particle. Depending on the nature of the symmetry of the particles, all elementary particles and the atoms and molecules built from them are divided into two classes. Particles with half-integer spin (for example, electrons, protons, neutrons) are described by asymmetric wave functions and obey Fermi-Dirac statistics. These particles are called fermions. Particles with integer spin, including zero, such as photon (Ls=1) or n-meson (Ls= 0) are described by symmetric wave functions and obey Bose-Einstein statistics. These particles are called bosons. Complex particles (for example, atomic nuclei), composed of an odd number of fermions, are also fermions (the total spin is half-integer), and those composed of an even number are bosons (the total spin is integer).

2.8. Multi-electron atom. Pauli principle

In a multi-electron atom whose charge is Ze, the electrons will occupy different "orbits" (shells). When moving around the nucleus, Z-electrons are arranged in accordance with a quantum mechanical law, which is called Pauli principle(1925). It is formulated like this:

> 1. In any atom, there cannot be two identical electrons determined by a set of four quantum numbers: the main n, orbital / magnetic m and magnetic spin m s .

> 2. In states with a certain value, no more than 2n 2 electrons can be in an atom.

This means that only 2 electrons can be on the first shell (“orbit”), 8 on the second, 18 on the third, etc.

Thus, the set of electrons in a multi-electron atom that have the same principal quantum number n is called electronic shell. In each of the shells, the electrons are arranged in subshells that correspond to a certain value of /. Since the orbital quantum number l takes values ​​from 0 to (n - 1), the number of subshells is equal to the ordinal number of the shell P. The number of electrons in a subshell is determined by the magnetic quantum number m l and magnetic spin number m s .

The Pauli principle has played an outstanding role in the development of modern physics. So, for example, it was possible to theoretically substantiate the periodic system of elements of Mendeleev. Without the Pauli principle, it would be impossible to create quantum statistics and the modern theory of solids.

2.9. Quantum-mechanical substantiation of the Periodic law of D. I. Mendeleev

In 1869, D. I. Mendeleev discovered the periodic law of change in the chemical and physical properties of elements depending on their atomic masses. D. I. Mendeleev introduced the concept of the serial number of the Z-element and, arranging the chemical elements in ascending order of their number, obtained a complete periodicity in the change in the chemical properties of the elements. The physical meaning of the serial number of the Z-element in the periodic system was established in Rutherford's nuclear model of the atom: Z coincides with the number of positive elementary charges in the nucleus (protons) and, accordingly, with the number of electrons in the shells of atoms.

The Pauli principle gives an explanation of the Periodic system of D. I. Mendeleev. Let's start with the hydrogen atom, which has one electron and one proton. Each subsequent atom will be obtained by increasing the charge of the nucleus of the previous atom by one (one proton) and adding one electron, which we will place in a state accessible to it, according to the Pauli principle.

At the hydrogen atom Z= 1 on the shell 1 electron. This electron is located on the first shell (K-shell) and has a state of 1S, that is, it has n=1,a l=0(S-state), m= 0, m s = ±l/2 (the orientation of its spin is arbitrary).

A helium (He) atom has Z = 2, there are 2 electrons on the shell, both of them are located on the first shell and have a state 1S, but with antiparallel orientation of the spins. On the helium atom, the filling of the first shell (K-shell) ends, which corresponds to the completion of the first period of the Periodic Table of Elements of D. I. Mendeleev. According to the Pauli principle, more than 2 electrons cannot be placed on the first shell.

At the lithium atom (Li) Z\u003d 3, there are 3 electron shells: 2 - on the first shell (K-shell) and 1 - on the second (L-shell). In the first shell, the electrons are in the state 1S, and on the second - 2S. Lithium begins the II period of the table.

At the beryllium atom (Be) Z= 4, on the shells 4 electrons: 2 on the first shell in the state IS and 2 on the second in the 2S state.

The next six elements - from B (Z = 5) to Ne (Z = 10) - are filling the second shell, while the electrons are both in the 2S state and in the 2p state (the second shell has 2 sub-shells).

At the sodium atom (Na) Z= 11. Its first and second shells, according to the Pauli principle, are completely filled (2 electrons on the first and 8 electrons on the second shells). Therefore, the eleventh electron is located on the third shell (M-shell), occupying the lowest state 3 S. Sodium opens the III period of the Periodic system of D. I. Mendeleev. Arguing in this way, you can build the entire table.

Thus, the periodicity in the chemical properties of elements is explained by the repeatability in the structure of the outer shells of atoms of related elements. So, inert gases have identical outer shells of 8 electrons.

2.10. Basic concepts of nuclear physics

The nuclei of all atoms can be divided into two large classes: stable and radioactive. The latter spontaneously decay, turning into nuclei of other elements. Nuclear transformations can also occur with stable nuclei when they interact with each other and with various microparticles.

Any nucleus is positively charged, and the magnitude of the charge is determined by the number of protons in the nucleus Z (charge number). The number of protons and neutrons in the nucleus determines the mass number of the nucleus A. Symbolically, the nucleus is written as follows:

where X- symbol of a chemical element. Nuclei with the same charge number Z and different mass numbers A are called isotopes. For example, uranium occurs in nature mainly in the form of two isotopes

Isotopes have the same chemical properties but different physical properties. For example, an isotope of uranium 2 3 5 92 U interact well with the neutron 1 0 n of any energy and can split into two lighter nuclei. At the same time, the uranium isotope 23892U is divided only when interacting with high-energy neutrons, more than 1 megaelectronvolt (MeV) (1 MeV = 1.6 10 -13 J). nuclei with the same A and different Z called isobars.

While the charge of the nucleus is equal to the sum of the charges of the protons entering it, the mass of the nucleus is not equal to the sum of the masses of individual free protons and neutrons (nucleons), it is somewhat less than it. This is explained by the fact that for the binding of nucleons in the nucleus (for the organization of strong interaction) the binding energy is required E. Each nucleon (both proton and neutron), getting into the nucleus, figuratively speaking, allocates a part of its mass for the formation of an intranuclear strong interaction, which "glues" the nucleons in the nucleus. At the same time, according to the theory of relativity (see Chapter 3), between the energy E and weight m there is a relation E = mc 2 , where With is the speed of light in vacuum. So the formation of the binding energy of nucleons in the nucleus E St. leads to a decrease in the mass of the nucleus by the so-called mass defect Δm = E St. c 2 . These ideas are confirmed by numerous experiments. Having plotted the dependence of the binding energy per nucleon Esv / A= ε on the number of nucleons in the nucleus A, we will immediately see the non-linear nature of this dependence. Specific binding energy ε with increasing A first increases steeply (for light nuclei), then the characteristic approaches the horizontal (for medium nuclei), and then slowly decreases (for heavy nuclei). Uranium has ε ≈ 7.5 MeV, while medium nuclei have ε ≈ 8.5 MeV. Medium nuclei are the most stable, they have a large binding energy. This opens up the possibility of obtaining energy by dividing a heavy nucleus into two lighter (medium) ones. Such a nuclear fission reaction can be carried out by bombarding a uranium nucleus with a free neutron. For instance, 2 3 5 92 U is divided into two new nuclei: rubidium 37 -94 Rb and cesium 140 55 Cs (one of the variants of uranium fission). The fission reaction of a heavy nucleus is remarkable in that, in addition to new lighter nuclei, two new free neutrons appear, which are called secondary. In this case, each fission event accounts for 200 MeV of the released energy. It is released in the form of the kinetic energy of all fission products and can then be used, for example, to heat water or another coolant. Secondary neutrons, in turn, can cause fission of other uranium nuclei. A chain reaction is formed, as a result of which huge energy can be released in the breeding medium. This method of generating energy is widely used in nuclear weapons and controlled nuclear power plants in power plants and transport facilities with nuclear power.

In addition to the indicated method of obtaining atomic (nuclear) energy, there is another one - the fusion of two light nuclei into a heavier nucleus. The process of unification of light nuclei can occur only when the initial nuclei approach each other at a distance where nuclear forces already act (strong interaction), that is, ~ 10 - 15 m. This can be achieved at ultrahigh temperatures of the order of 1,000,000 °C. Such processes are called thermonuclear reactions.

Thermonuclear reactions in nature take place in stars and, of course, in the Sun. Under the conditions of the Earth, they occur during the explosions of hydrogen bombs (thermonuclear weapons), the fuse for which is a conventional atomic bomb, which creates conditions for the formation of ultrahigh temperatures. Controlled thermonuclear fusion has so far only a research focus. There are no industrial installations, but work in this direction is being carried out in all developed countries, including Russia.

2.11. Radioactivity

Radioactivity is the spontaneous transformation of one nucleus into another.

Spontaneous decay of isotopes of nuclei in the natural environment is called natural, and in laboratory conditions as a result of human activity - artificial radioactivity.

Natural radioactivity was discovered by the French physicist Henri Becquerel in 1896. This discovery caused a revolution in natural science in general and in physics in particular. Classical physics of the XIX century. with its conviction in the indivisibility of the atom, it has become a thing of the past, giving way to new theories.

The discovery and study of the phenomenon of radioactivity is also associated with the names of Marie and Pierre Curie. These researchers were awarded the Nobel Prize in Physics in 1903.

Artificial radioactivity was discovered and studied by the spouses Irene and Frederic Joliot-Curie, who also received the Nobel Prize in 1935.

It should be noted that there is no fundamental difference between these two types of radioactivity.

Quantitative estimates have been established for each radioactive element. Thus, the probability of the decay of one atom in one second is characterized by the decay constant of the given element l, and the time for which half of the radioactive sample decays is called the half-life Г 05.

Over time, the number of undecayed nuclei N decreases exponentially:

N= N 0 e -λt ,

where N 0 is the number of undecayed nuclei at a time t = t 0 (that is, the initial number of atoms), N- the current value of the number of undecayed

This law is called the elementary law of radioactive decay. From it you can get the formula for the half-life:

The number of radioactive decays in a sample in one second is called the activity of the radioactive drug. Most often, activity is denoted by the letter A then by definition:

where the sign "-" means decreasing N in time.

The unit of activity in the SI system is Becquerel (Bq): 1 Bq = 1 decay / 1 s. Often in practice, an off-system unit is used - Curie (Ci), 1 Ci \u003d 3.7 10 10 Bq.

It can be shown that activity decreases with time also according to an exponential law:

A=A 0 e -λt .

Questions for self-examination

1. What is matter? What types of matter are distinguished in the modern view?

2. Explain the concept of "elementary particles". Name the most important characteristics of elementary particles. How are elementary particles classified?

3. How many types of interaction do you know? List their main features.

4. What are antiparticles?

5. What is the specificity of the study of the microcosm in comparison with the study of the mega- and macrocosms?

6. Describe briefly the history of the development of ideas about the structure of the atom.

7. Formulate N. Bohr's postulates. Is it possible to explain the structure of atoms of all elements of the table of D. I. Mendeleev using the theory of N. Bohr?

8. Who and when created the theory of the electromagnetic field?

9. What is radioactivity?

10. Name the main types of radioactive decay.

MATTER AND FIELD

The concept of a field was formed gradually, one might say, throughout the 19th century. It was this that marked the beginning of the formation of non-classical science and philosophy. Field is a very strange concept. Fields are integral components of any particles known to science. Each electron, for example, has three fields: electromagnetic, gravitational, and so-called. field is weak. First of all, we are now interested in the question, do particles have fields in the entire Universe? We must first understand the very essence of the fields in order to answer this question. But in general, to begin with, the inherent nature of fields to all particles in the entire infinite Universe can be assumed. Although the specific types of fields there are - of course, different than those of particles in the Universe - and are infinitely diverse.

What characterizes the field in general? To begin with, any field is characterized, firstly, by tension, and, secondly, by an infinite extension in space. The last property is just the most strange and hard to imagine. To imagine this property (i.e., unlimited extension), let's take, for example, an ordinary magnet: the magnetic field strength of a magnet decreases with increasing distance from the magnet, and soon becomes scanty, but zero - not at any, even at the most enormous distance - does not reach! Magnet field size t. - limitless. And since the field is just a part of the magnet as an object, then the magnet itself turns out to have unlimited dimensions (!), i.e., unlimited extension in space. It is very strange and unusual, but nevertheless, it is so.

All fields have infinite dimensions; and since the fields are considered to be integral components of every particle in the Universe, then every particle, therefore, also has an infinite size (= infinite extension in space), and therefore cannot have either a surface, or a geometric shape, or a certain size. Such ideas about particles (and objects in general) still seem unusual, but they are, in general, modern ideas and about electrons, and about atoms, and even about macroobjects. And these ideas can easily be extended to the entire infinite Universe.

Further: each separate existing field (as, for example, the electromagnetic field of a separate electron) is a certain, separate from others, continuous substance, which has an unlimited extent. Any field is a part of some, this or that, particle (or macroobject). A field is a matter-like foundation present in any particle along with matter (represented by the so-called material core). In any particle, so. there are two grounds at the same time: both matter and field (/ fields). An electron, for example, so. consists - of a material core, surrounded by three fields (electromagnetic, gravitational, and "weak"), infinitely continuing in all directions from the material core.

Thanks to the fields, and their unlimited extent in space, any particle is unlimited, and interacts, at the same time, at least with all the particles that are in the Universe ... (although the intensity of interactions is great and significant only with the "most closely spaced" particles; all the same other interactions can, to a certain extent, be neglected).

Further: any field is not a full-fledged substance, i.e., a semi-substance, because the field has only one of the two substantial properties: the field has an extension (limitless), but it is completely devoid of density (hardness). (Tension is not density at all!). Any field is tense, but absolutely ethereal.

At each point of the cosmic vacuum - there are fields, at the same time, at least, from all the particles present in the Universe, and the vacuum thus. - filled with fields to capacity! but nevertheless, the vacuum is transparent and incorporeal, for such are the fields. As a result, vacuum is not emptiness, and thus emptiness. - does not exist at all, because everything around is filled to overflowing with (boundless) fields. But at the same time, this absence of emptiness does not in the least prevent the movement of particles!

That. in non-classical times, a solution is found, how the movement can be carried out in the conditions of the complete absence of emptiness (= non-existence of non-existence).

The Battlefield The martial arts may serve as a figurative metaphor for all of life, yet the Path of the Peaceful Warrior rarely involves encounters with outside foes. The hardest battles are hidden deep inside the soul - in the depths of ourselves we fight our fears,