The concept of matter is the structural levels of the organization of matter briefly. Control work structural levels of the organization of matter. The origin of inanimate matter, the universe
The materialistic understanding of substance has passed more than two thousand years of development. It began with a simplified idea of the foremother, i.e. about something that predates modern matter and is therefore substance.
The concept of matter is a fundamental category in philosophy and natural science. In Latin, materia means substance. The initial ideas about matter arose already in antiquity, where representatives of various philosophical schools identified it with the material substance underlying being: water (Thales), air (Anaximenes), fire (Heraclitus), atoms (Democritus), etc.
In the Middle Ages, matter was understood mainly as the material from which things are made. Matter as a philosophical category did not develop, although we find in St. Augustine the concept of “spiritual and bodily matter”.
In the XVII - XVIII centuries. a new understanding of matter is emerging, different from the ideas of the ancients. It was concluded that matter is not a specific substance (earth, fire, water, air, etc.), but a physical reality as such. During this period, mathematical, natural ideas sprout from philosophy and develop as independent branches. social Sciences. The most developed sciences of that time were mechanics and geometry, therefore mechanism prevailed in the views on matter. Matter is defined as a collection of sensually perceived bodies. Matter is identified with matter, consisting of indivisible, immutable atoms, possessing universal properties: mechanical mass, weight, impenetrability, inertia. Everything material has these properties, which means that it is quite logical to transfer these properties from specific substances to the Substance as such.
At the same time, the definition of matter appeared, given by the English philosopher J. Berkeley, a classic of subjective idealism. In his work "Dialogue between the Philosopher Berkeley and the Materialist," he puts into the mouth of the materialist the concept of matter as a reality that affects our sensations, but does not depend on them. Berkeley, being a subjective idealist, directed all his philosophical energy to the struggle against materialism and its basic concept - matter, but it was the definition of matter given by him that was used by the French materialists, who understood by matter everything that acts on our senses. Under this everything that acts on our senses, they meant a substance, which is a collection of specific particles-atoms, identical to each other, having universal properties. The basis of matter-substance is the fundamental laws of the universe, and above all the law of conservation of matter.
This understanding of matter was historically progressive, but also limited. The German philosopher F. Engels was the first to point out this limitation. He believed that matter cannot be reduced to a set of specific particles-atoms, since they themselves can have a complex structure. He owns the definition of matter as general concept covering all kinds of things.
The limitations of the concept of identifying matter with substance became especially obvious for natural science at the turn of the 19th-20th centuries. It was during that period that a crisis broke out in physics associated with revolutionary discoveries.
As one of the options for overcoming the crisis and further development of physics and philosophy, V.I. Lenin proposed a new methodological basis - a new definition of matter: "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."
Lenin believed that it was necessary to distinguish between the philosophical understanding of matter and physical ideas about its properties and structure, and gave a philosophical definition, focusing on the fact that matter as a category does not mean anything other than objective reality, which means that no matter what new state of matter, it is enough to determine whether this discovery is an objective reality or not. Further, with his definition, he emphasized that matter is the primary reality in relation to our sensations, since it exists independently of them.
Lenin's definition is more dialectical than previous metaphysical definitions, since it is open to subsequent knowledge and development. But, like any definition, it is historically limited. It is rather epistemological than ontological, because to say that matter is an objective reality is to say nothing in terms of content. This definition works against subjective idealism, but does not work at all against objective idealism. After all, God, and the world mind, and the absolute idea fit into the definition of objective reality for a person who believes in them. God appears to the believer in a specific image, which he perceives with the help of the senses.
But, despite these shortcomings, in materialism today there is no newer and more perfect definition of matter. Along with the worldview, the methodological significance of this definition for the development of natural science should also be noted. The idea of the inexhaustibility of matter, expressed by V.I. Lenin, is now one of the guiding methodological principles of natural science research. This is especially clearly manifested in modern views on the structure of matter that have developed in the natural sciences.
Let us briefly characterize the modern ideas about structural organization of matter. Structural levels of matter are formed from a certain set of objects of any class and are characterized by a special type of interaction between their constituent elements. The criteria for distinguishing structural levels are space-time scales, the totality of the most important properties and laws of change, the degree of relative complexity that arose in the process of the historical development of matter in a given area of the world.
inorganic nature is divided into three 1) micro-, 2) macro- and 3) megaworlds, having the following sequence of structural levels: 1) submicroelementary - microelementary (elementary particles and field interactions) - nuclear - atomic - molecular - 2) level of macroscopic bodies (a number of sublevels ) - 3) planets - star-planetary complexes - galaxies - metagalaxies.
Live nature is subdivided into the following levels: biological macromolecules - cellular level - microorganism - organs and tissues - organism as a whole - population - biocenosis - biospheric. The general basis of life - organic metabolism (exchange of matter, energy and information with the environment) - is specified in each of the distinguished levels.
social reality represented by levels: individuals - families - collectives - social groups - classes - nationalities and nations - states and systems of states - society as a whole.
We also note that higher levels of the systemic organization of matter arise within a relatively small set of phenomena previous level. So, out of the three main groups of levels of inorganic nature (micro-, macro- and mega-world), life arises only at the level of a smaller part of the phenomena of the macro-world, just as society arises in representatives of a single biological species. The complication of the systemic organization of matter is thus accompanied by a narrowing of the possibilities for its implementation.
Moscow Open Social Academy
Department of Mathematical and General Natural Sciences
Concepts of modern natural science.
Abstract topic:
Structural levels of matter organization.
Faculty of Correspondence Education
group number: FEB-3.6
Supervisor:
Moscow 2009
INTRODUCTION
I. Structural levels of matter organization: micro-, macro-, mega-worlds
1.1 Modern view on the structural organization of matter
II. Structure and its role in the organization of living systems
2.1 System and whole
2.2 Part and element
2.3 Interaction of part and whole
III. Atom, man, the universe - a long chain of complications
CONCLUSION REFERENCES
Introduction
All objects of nature (living and inanimate nature) can be represented as a system with features that characterize their levels of organization. The concept of structural levels of living matter includes representations of systemicity and the organization of the integrity of living organisms associated with it. Living matter is discrete, i.e. is divided into constituent parts of a lower organization that have certain functions. Structural levels differ not only in complexity classes, but also in the patterns of functioning. The hierarchical structure is such that each higher level does not control, but includes the lower one. The diagram most accurately reflects a holistic picture of nature and the level of development of natural science as a whole. Taking into account the level of organization, it is possible to consider the hierarchy of the organization structures of material objects of animate and inanimate nature. Such a hierarchy of structures begins with elementary particles and ends with living communities. The concept of structural levels was first proposed in the 1920s. our century. In accordance with it, the structural levels differ not only in classes of complexity, but in the patterns of functioning. The concept includes a hierarchy of structural levels, in which each next level is included in the previous one.
The purpose of this work is to study the concept of the structural organization of matter.
I. Structural levels of matter organization: micro-, macro-, mega-worlds
AT modern science At the heart of ideas about the structure of the material world is a systematic approach, according to which any object of the material world, be it an atom, a planet, etc. can be considered as a system - a complex formation, including components, elements and connections between them. The element in this case means the minimum, further indivisible part of the given system.
The set of connections between elements forms the structure of the system, stable connections determine the orderliness of the system. Horizontal links are coordinating, they provide correlation (consistency) of the system, no part of the system can change without changing other parts. Vertical links are links of subordination, some elements of the system are subordinate to others. The system has a sign of integrity - this means that all its constituent parts, when combined into a whole, form a quality that cannot be reduced to the qualities of individual elements. According to modern scientific views, all natural objects are ordered, structured, hierarchically organized systems.
In the most general sense of the word "system" refers to any object or any phenomenon of the world around us and represents the relationship and interaction of parts (elements) within the framework of the whole. The structure is the internal organization of the system, which contributes to the connection of its elements into a single whole and gives it unique features. The structure determines the ordering of the elements of an object. Elements are any phenomena, processes, as well as any properties and relationships that are in some kind of mutual connection and relationship with each other.
In understanding the structural organization of matter, the concept of “development” plays an important role. The concept of the development of inanimate and living nature is considered as an irreversible directed change in the structure of objects of nature, since the structure expresses the level of organization of matter. The most important property of a structure is its relative stability. Structure is a general, qualitatively defined and relatively stable order of internal relations between the subsystems of a particular system. The concept of "level of organization", in contrast to the concept of "structure", includes the idea of a change in structures and its sequence in the course of the historical development of the system from the moment of its inception. While the change in structure may be random and not always directed, the change in the level of organization occurs in a necessary way.
Systems that have reached the appropriate level of organization and have a certain structure acquire the ability to use information in order to maintain unchanged (or increase) their level of organization through control and contribute to the constancy (or decrease) of their entropy (entropy is a measure of disorder). Until recently, natural science and other sciences could do without a holistic, systematic approach to their objects of study, without taking into account the study of the processes of formation of stable structures and self-organization.
At present, the problems of self-organization studied in synergetics are becoming relevant in many sciences, from physics to ecology.
The task of synergetics is to clarify the laws of building an organization, the emergence of order. Unlike cybernetics, here the emphasis is not on the processes of managing and exchanging information, but on the principles of building an organization, its emergence, development and self-complication (G. Haken). The question of optimal ordering and organization is especially acute in the study of global problems - energy, environmental, and many others that require the involvement of huge resources.
1.1 MODERN VIEWS ON THE STRUCTURAL ORGANIZATION OF MATTER
In classical natural science, the doctrine of the principles of the structural organization of matter was represented by classical atomism. The ideas of atomism served as the foundation for the synthesis of all knowledge about nature. In the 20th century, classical atomism underwent a radical transformation.
Modern principles of the structural organization of matter are associated with the development of system concepts and include some conceptual knowledge about the system and its features that characterize the state of the system, its behavior, organization and self-organization, interaction with the environment, purposefulness and predictability of behavior, and other properties.
The simplest classification of systems is their division into static and dynamic, which, despite its convenience, is still conditional, because. everything in the world is in constant change. Dynamic systems are divided into deterministic and stochastic (probabilistic). This classification is based on the nature of predicting the dynamics of the behavior of systems. Such systems are studied in mechanics and astronomy. In contrast to them, stochastic systems, which are usually called probabilistic - statistical, deal with massive or repetitive random events and phenomena. Therefore, the predictions in them are not reliable, but only probabilistic.
By the nature of interaction with the environment, open and closed (isolated) systems are distinguished, and sometimes they are also partially isolated. open systems. Such a classification is mostly conditional, because the concept of closed systems arose in classical thermodynamics as a certain abstraction. The vast majority, if not all, of the systems are open source.
Many complex systems found in the social world are purposeful, i.e. focused on achieving one or more goals, and in different subsystems and at different levels of the organization, these goals can be different and even come into conflict with each other.
The classification and study of systems made it possible to develop a new method of cognition, which was called the system approach. The application of system ideas to the analysis of economic and social processes contributed to the emergence of game theory and decision theory. The most significant step in the development of the system method was the emergence of cybernetics as a general theory of control in technical systems, living organisms and society. Although separate control theories existed before cybernetics, the creation of a unified interdisciplinary approach made it possible to reveal deeper and general patterns management as a process of accumulation, transmission and transformation of information. The control itself is carried out with the help of algorithms, for the processing of which computers are used.
The universal theory of systems, which determined the fundamental role of the system method, expresses, on the one hand, the unity of the material world, and, on the other hand, the unity of scientific knowledge. An important consequence of this consideration of material processes was the limitation of the role of reduction in the cognition of systems. It became clear that the more some processes differ from others, the more qualitatively they are heterogeneous, the more difficult it is to reduce. Therefore, the laws of more complex systems cannot be completely reduced to the laws of lower forms or simpler systems. As an antipode to the reductionist approach, a holistic approach arises (from the Greek holos - the whole), according to which the whole always precedes the parts and is always more important than the parts.
Every system is a whole, formed by its interconnected and interacting parts. Therefore, the process of cognition of natural and social systems can be successful only when the parts and the whole in them are studied not in opposition, but in interaction with each other.
Modern science considers systems as complex, open, with many possibilities for new ways of development. The processes of development and functioning of a complex system have the nature of self-organization, i.e. the emergence of internally coordinated functioning due to internal connections and connections with the external environment. Self-organization is a natural scientific expression of the process of self-movement of matter. The ability for self-organization is possessed by systems of animate and inanimate nature, as well as artificial systems.
In the modern scientifically based concept of the systemic organization of matter, three structural levels of matter are usually distinguished:
microcosm - the world of atoms and elementary particles - extremely small directly unobservable objects, the dimension is from 10-8 cm to 10-16 cm, and the lifetime is from infinity to 10-24 s.
the macroworld is the world of stable forms and human-sized values: earthly distances and velocities, masses and volumes; the dimension of macroobjects is comparable with the scale of human experience - spatial dimensions from fractions of a millimeter to kilometers and temporal measurements from fractions of a second to years.
megaworld - the world of space (planets, star complexes, galaxies, metagalaxies); the world of huge cosmic scales and speeds, the distance is measured in light years, and time in millions and billions of years;
The study of the hierarchy of structural levels of nature is connected with the solution of the most difficult problem of determining the boundaries of this hierarchy both in the mega-world and in the micro-world. The objects of each subsequent stage arise and develop as a result of the union and differentiation of certain sets of objects of the previous stage. Systems are becoming more and more tiered. The complexity of the system increases not only because the number of levels increases. Of essential importance is the development of new relationships between levels and with the environment common to such objects and their associations.
The microworld, being a sublevel of the macroworlds and megaworlds, has completely unique features and therefore cannot be described by theories related to other levels of nature. In particular, this world is inherently paradoxical. For him, the principle "consists of" does not apply. So, when two elementary particles collide, no smaller particles are formed. After the collision of two protons, many other elementary particles arise - including protons, mesons, hyperons. The phenomenon of "multiple production" of particles was explained by Heisenberg: during the collision, a large kinetic energy is converted into matter, and we observe the multiple birth of particles. The microworld is being actively studied. If 50 years ago only 3 types of elementary particles were known (electron and proton as the smallest particles of matter and photon as the minimum portion of energy), now about 400 particles have been discovered. The second paradoxical property of the microcosm is associated with the dual nature of a microparticle, which is both a wave and a corpuscle. Therefore, it cannot be strictly unambiguously localized in space and time. This feature is reflected in the Heisenberg uncertainty relation principle.
The levels of matter organization observed by man are mastered taking into account the natural conditions of human habitation, i.e. taking into account our earthly laws. However, this does not exclude the assumption that forms and states of matter, characterized by completely different properties, may exist at levels far enough from us. In this regard, scientists began to distinguish geocentric and non-geocentric material systems.
Geocentric world - the reference and basic world of Newtonian time and Euclidean space, is described by a set of theories related to objects on the earth's scale. Non-geocentric systems are a special type of objective reality, characterized by other types of attributes, other space, time, movement than earthly ones. There is an assumption that the microworld and the megaworld are windows into non-geocentric worlds, which means that their laws, at least to a remote extent, make it possible to imagine a different type of interaction than in the macrocosm or the geocentric type of reality.
There is no strict boundary between the mega world and the macro world. It is usually assumed that he
starts with distances of about 107 and masses of 1020 kg. The reference point for the beginning of the mega-world can be the Earth (diameter 1.28×10+7 m, weight 6×1021 kg). Since the megaworld deals with large distances, special units are introduced for their measurement: an astronomical unit, a light year and a parsec.
astronomical unit (a.u.) – the average distance from the Earth to the Sun, equal to 1.5 × 1011 m.
Light year – the distance that light travels in one year, namely 9.46 × 1015 m.
Parsec (parallax second) – the distance at which the annual parallax of the earth's orbit (i.e. the angle at which the semi-major axis of the earth's orbit is visible, located perpendicular to the line of sight) is equal to one second. This distance is 206265 AU. \u003d 3.08 × 1016 m \u003d 3.26 sv. G.
Celestial bodies in the Universe form systems of varying complexity. So the Sun and 9 planets moving around it form solar system. The main part of the stars of our galaxy is concentrated in the disk, visible from the Earth "from the side" in the form of a foggy strip that crosses the celestial sphere - the Milky Way.
All celestial bodies have their own history of development. The age of the Universe is 14 billion years. The age of the solar system is estimated at 5 billion years, the Earth - 4.5 billion years.
Another typology of material systems is quite widespread today. This is the division of nature into inorganic and organic, in which the social form of matter occupies a special place. Inorganic matter is elementary particles and fields, atomic nuclei, atoms, molecules, macroscopic bodies, geological formations. Organic matter also has a multi-level structure: pre-cellular level - DNA, RNA, nucleic acids; cellular level - independently existing unicellular organisms; multicellular level - tissues, organs, functional systems (nervous, circulatory, etc.), organisms (plants, animals); supraorganismal structures - populations, biocenoses, biosphere. Social matter exists only thanks to the activities of people and includes special substructures: an individual, a family, a group, a collective, a state, a nation, etc.
II. STRUCTURE AND ITS ROLE IN THE ORGANIZATION OF LIVING SYSTEMS
2.1 SYSTEM AND WHOLE
A system is a set of interacting elements. Translated from Greek, this is a whole, made up of parts, a connection.
Having endured a long historical evolution, the concept of a system from the middle of the 20th century. becomes one of the key scientific concepts.
Primary ideas about the system arose in ancient philosophy as orderliness and the value of being. The concept of a system now has an extremely wide scope: almost every object can be considered as a system.
Each system is characterized not only by the presence of connections and relationships between its constituent elements, but also by its inseparable unity with the environment.
There are different types of systems:
By the nature of the connection between parts and the whole - inorganic and organic;
According to the forms of motion of matter - mechanical, physical, chemical, physico-chemical;
In relation to movement - statistical and dynamic;
By types of changes - non-functional, functional, developing;
By the nature of the exchange with the environment - open and closed;
According to the degree of organization - simple and complex;
According to the level of development - lower and higher;
By nature of origin - natural, artificial, mixed;
In the direction of development - progressive and regressive.
According to one of the definitions, the whole is that which does not lack any of the parts, consisting of which, it is called the whole. The whole necessarily presupposes the systemic organization of its components.
The concept of the whole reflects the harmonic unity and interaction of parts according to a certain ordered system.
The affinity of the concepts of the whole and the system served as the basis for their not entirely correct complete identification. In the case of a system, we are not dealing with a single object, but with a group of interacting objects that mutually influence each other. With further improvement of the system towards the orderliness of its components, it can move into integrity. The concept of the whole characterizes not only the multiplicity of constituent components, but also the fact that the connection and interaction of parts are natural, arising from the internal needs of the development of parts and the whole.
Therefore, the whole is a special kind of system. The concept of the whole is a reflection of the internally necessary, organic nature of the interconnection of the components of the system, and sometimes a change in one of the components inevitably causes one or another change in the other, and often in the entire system.
The properties and mechanism of the whole as a higher level of organization in comparison with the parts organizing it cannot be explained only by summing up the properties and moments of action of these parts, considered in isolation from each other. New properties of the whole arise as a result of the interaction of its parts; law of association of parts.
Since the whole as a qualitative certainty is the result of the interaction of its components, it is necessary to dwell on their characteristics. Being components of a system or a whole, the components enter into various relationships with each other. Relations between elements can be divided into "element - structure" and "part - whole". In the system of the whole, the subordination of parts to the whole is observed. The system of the whole is characterized by the fact that it can create the organs it lacks.
2.2 PART AND ELEMENT
An element is such a component of an object that may be indifferent to the specifics of the object. In the category of structure, one can find a connection relationship and a relationship between elements that are indifferent to its specificity.
A part is also an integral component of an object, but, unlike an element, a part is a component that is not indifferent to the specifics of the object as a whole (for example, a table consists of parts - a lid and legs, as well as elements that fasten parts of screws, bolts, which can be used to fasten other items: cabinets, cabinets, etc.)
A living organism as a whole consists of many components. Some of them will be just elements, others at the same time and parts. Parts are only such components that are inherent in the functions of life (metabolism, etc.): extracellular living matter; cell; the cloth; organ; organ system.
All of them have the functions of a living thing, they all perform their specific functions in the organization system of the whole. Therefore, a part is such a component of the whole, the functioning of which is determined by the nature, the essence of the whole itself.
In addition to parts, there are other components in the body that do not possess the functions of life by themselves, i.e. are non-living components. These are the elements. Non-living elements are present at all levels of the systemic organization of living matter:
In the protoplasm of the cell - grains of starch, drops of fat, crystals;
In a multicellular organism, non-living components that do not have their own metabolism and the ability to reproduce themselves include hair, claws, horns, hooves, feathers.
Thus, the part and the element constitute the necessary components of the organization of the living as an integral system. Without elements (non-living components), the functioning of parts (living components) is impossible. Therefore, only the cumulative unity of both elements and parts, i.e. inanimate and living components, constitutes the systemic organization of life, its integrity.
2.2.1 RELATIONSHIP OF CATEGORIES PART AND ELEMENT
The correlation between the categories part and element is highly contradictory. The content of the part category differs from the element category: elements are all the constituent components of the whole, regardless of whether the specificity of the whole is expressed in them or not, and parts are only those elements in which the specificity of the object as a whole is directly expressed, therefore the category of the part is narrower than the category of the element. On the other hand, the content of the category of a part is wider than the category of an element, since only a certain set of elements constitutes a part. And this can be shown for any whole.
This means that there are certain levels or boundaries in the structural organization of the whole, which separate elements from parts. At the same time, the difference between the categories part and element is very relative, since they can interconvert, for example, organs or cells, while functioning, undergo destruction, which means that they turn from parts into elements and vice versa, they are again built from inanimate, i.e. . elements, and become parts. Elements not removed from the body can turn into salt deposits, which are already part of the body, and quite undesirable.
2.3 INTERACTION OF THE PART AND THE WHOLE
The interaction of the part and the whole lies in the fact that one presupposes the other, they are one and cannot exist without each other. There is no whole without a part and vice versa: there are no parts outside the whole. A part becomes a part only in the system of the whole. The part acquires its meaning only through the whole, just as the whole is the interaction of the parts.
In the interaction of the part and the whole, the leading, determining role belongs to the whole. Parts of the body cannot exist on their own. Representing individual adaptive structures of the organism, parts arise in the course of evolution for the sake of the whole organism.
The determining role of the whole in relation to the parts in organic nature is best confirmed by the phenomena of autotomy and regeneration. The lizard, grabbed by the tail, runs away, leaving the tip of the tail. The same thing happens with the claws of crabs, crayfish. Autotomy, i.e. self-cutting of the tail in a lizard, claws in crabs and crayfish, is a protective function that contributes to the adaptation of the organism, developed in the evolutionary process. The organism sacrifices its part in the interests of saving and preserving the whole.
The phenomenon of autotomy is observed in cases where the body is able to restore the lost part. The missing part of the lizard's tail grows again (but only once). Crabs and crayfish also often grow broken claws. This means that the body is able to first lose a part for the sake of saving the whole, in order to restore this part later.
The phenomenon of regeneration testifies even more to the subordination of the parts to the whole: the whole necessarily requires the fulfillment to some extent of the lost parts. Modern biology has established that not only low-organized creatures (plants and protozoa) have a regenerative ability, but also mammals.
There are several types of regeneration: not only individual organs are restored, but also entire organisms from its individual sections (hydra from a ring cut from the middle of its body, protozoa, coral polyps, annelids, sea stars etc.). In Russian folklore, we know the Serpent-Gorynych, whose heads were cut off by good fellows, who immediately grew back ... In general biological terms, regeneration can be considered as the ability of an adult organism to develop.
However, the defining role of the whole in relation to the parts does not mean that the parts are devoid of their specificity. The determining role of the whole presupposes not a passive, but an active role of the parts, aimed at ensuring the normal life of the organism as a whole. Subordinating to the general system of the whole, the parts retain relative independence and autonomy. On the one hand, the parts act as components of the whole, and on the other hand, they themselves are a kind of integral structures, systems with their own specific functions and structures. In a multicellular organism, of all parts, it is the cells that represent the highest level of integrity and individuality.
The fact that the parts retain their relative independence and autonomy allows for the relative independence of the study of individual organ systems: spinal cord, autonomic nervous system, digestive systems, etc., which is of great importance for practice. An example of this is the study and disclosure of the internal causes and mechanisms of the relative independence of malignant tumors.
The relative independence of parts, to a greater extent than animals, is inherent in plants. They are characterized by the formation of some parts from others - vegetative reproduction. Everyone, probably, in his life had to see cuttings of other plants grafted, for example, on an apple tree.
3..ATOM, MAN, UNIVERSE - A LONG CHAIN OF COMPLICATIONS
In modern science, the method of structural analysis is widely used, which takes into account the systematic nature of the object under study. After all, structure is the internal dismemberment of material existence, a way of existence of matter. Structural levels of matter are formed from a certain set of objects of any 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 as follows.
| STRUCTURAL LEVELS OF MATTER | |||
inorganic | Society | ||
| 1 | Submicroelementary | Biological macromolecular | Individual |
| 2 | Microelementary | Cellular | Family |
| 3 | Nuclear | microorganic | Collectives |
| 4 | Atomic | Organs and tissues | Large social groups (classes, nations) |
| 5 | Molecular | Whole body | State (civil society) |
| 6 | macro level | population | State systems |
| 7 | Mega level (planets, star-planet systems, galaxies) | Biocenosis | Humanity |
| 8 | Meta level (metagalaxies) | Biosphere | Noosphere |
Each of the spheres of objective reality includes a number of interrelated structural levels. Within these levels, coordination relations are dominant, and between levels, subordinate ones.
A systematic study of material objects involves not only the establishment of ways to describe the relationships, connections and structure of many elements, but also the selection of those of them that are system-forming, i.e., provide separate functioning and development of the system. A systematic approach to material formations implies the possibility of understanding the system under consideration at a higher level. The system is usually characterized by a hierarchical structure, i.e., the sequential inclusion of a lower-level system into a higher-level system. Thus, the structure of matter at the level of inanimate nature (inorganic) includes elementary particles, atoms, molecules (objects of the microworld, macrobodies and objects of the megaworld: planets, galaxies, systems of metagalaxies, etc.). The metagalaxy is often identified with the entire Universe, but the Universe is understood in the broadest sense of the word, it is identical to the entire material world and moving matter, which can include many metagalaxies and other space systems.
Wildlife is also structured. It highlights the biological level and the social level. The biological level includes sublevels:
Macromolecules (nucleic acids, DNA, RNA, proteins);
Cellular level;
Microorganic (single-celled organisms);
Organs and tissues of the body as a whole;
population;
Biocenosis;
Biospheric.
The main concepts of this level at the last three sublevels are the concepts of biotope, biocenosis, biosphere, which require explanation.
Biotope - a collection (community) of the same species (for example, a pack of wolves) that can interbreed and produce their own kind (populations).
Biocenosis - a set of populations of organisms in which the waste products of some are the conditions for the existence of other organisms inhabiting a land or water area.
Biosphere is a global system of life, that part of the geographic environment (lower part of the atmosphere, upper part of the lithosphere and hydrosphere), which is the habitat of living organisms, providing the conditions necessary for their survival (temperature, soil, etc.), formed as a result of interaction biocenoses.
The general basis of life at the biological level - organic metabolism (exchange of matter, energy and information with the environment) manifests itself at any of the distinguished sublevels:
At the level of organisms, metabolism means assimilation and dissimilation through intracellular transformations;
At the level of ecosystems (biocenosis), it consists of a chain of transformation of a substance originally assimilated by producer organisms through consumer organisms and destroyer organisms belonging to different species;
At the level of the biosphere, there is a global circulation of matter and energy with the direct participation of cosmic scale factors.
At a certain stage in the development of the biosphere, special populations of living beings arise, which, thanks to their ability to work, have formed a kind of level - the social level. Social activity in the structural aspect is divided into sublevels: individuals, families, various teams (production), social groups, etc.
The structural level of social activity is in ambiguous linear relationships with each other (for example, the level of nations and the level of states). The interweaving of different levels within society gives rise to the idea of the dominance of chance and chaos in social activity. But a careful analysis reveals the presence of fundamental structures in it - the main spheres of public life, which are the material and production, social, political, spiritual spheres, which have their own laws and structures. All of them, in a certain sense, are subordinated as part of the socio-economic formation, deeply structured and determine the genetic unity of social development as a whole. Thus, any of the three areas of material reality is formed from a number of specific structural levels that are in strict order within a particular area of reality. The transition from one area to another is associated with the complication and increase in the set of formed factors that ensure the integrity of systems. Within each of the structural levels there are relationships of subordination (the molecular level includes the atomic level, and not vice versa). The patterns of new levels are irreducible to the patterns of levels on the basis of which they arose, and are leading for a given level of matter organization. Structural organization, i.e. system, is a way of existence of matter.
Conclusion
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 of matter organization are built on the principle of a pyramid: the highest levels consist of a large number of lower levels. The lower levels are the basis of the existence of matter. Without these levels, further construction of the "pyramid of matter" is impossible. Higher (complex) levels are formed through evolution - gradually moving from simple to complex. Structural levels of matter are formed from a certain set of objects of any kind and are characterized by a special way of interaction between their constituent elements.
All objects of animate and inanimate nature can be represented as certain systems that have specific features and properties that characterize their level of organization. Taking into account the level of organization, it is possible to consider the hierarchy of the organization structures of material objects of animate and inanimate nature. Such a hierarchy of structures begins with elementary particles, which are the initial level of matter organization, and ends with living organizations and communities - the highest levels of organization.
The concept of structural levels of living matter includes representations of systemicity and the organic integrity of living organisms associated with it. However, the history of systems theory began with a mechanistic understanding of the organization of living matter, according to which everything higher was reduced to the lower: life processes - to a set of physicochemical reactions, and the organization of an organism - to the interaction of molecules, cells, tissues, organs, etc.
Bibliography
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2. Naidysh V.M. Concepts of modern natural science: Textbook.. Ed. 2nd, revised. and additional – M.; Alpha-M; INFRA-M, 2004. - 622 p.
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Matter organization system
Matter has a diverse, granular, discontinuous structure. It consists of parts of various sizes, qualitative certainty: elementary particles, atoms, molecules, radicals, ions, complexes, macromolecules, colloidal particles, planets, stars and their systems, galaxies. More than 30 different elementary particles have now been discovered, and together with resonances (particles that live a very short time), there are about 100 of them.
With "discontinuous" forms of matter, "continuous" forms are inseparably connected. These are different types of fields - gravitational, electromagnetic, nuclear. They bind particles of matter, allow them to interact and thus exist.
All particles, regardless of nature, have wave properties. Conversely, any continuous field is also a collection of particles. Such is the real contradiction in the structure of matter. The world and everything in the world is not chaos, but a regularly organized system, a hierarchy of systems. The structure of matter means an internally dissected integrity, a regular order of connection of elements in the composition of the whole. Basics modern philosophy: Textbook / Ed. M.N. Rosenko. - SPb.: Publishing house "Lan", 1999. S. 84. The existence and movement of matter are impossible outside of its structural organization.
Basic structural levels of matter.
The ordering of matter has its own levels, each of which is characterized by a special system of regularities and its carrier. The main structural levels of the mother are as follows. Submicroelementary level- a hypothetical form of existence of field nature matter, from which elementary particles are born ( microelement level), then nuclei are formed ( nuclear level), atoms arise from nuclei and electrons ( atomic level), and of them - molecules ( molecular level), aggregates are formed from molecules - gaseous, liquid, solid bodies ( macroscopic level). Formed bodies embrace stars with their satellites, planets with their satellites, stellar systems, their enclosing metagalaxies. And so on to infinity space level).
In addition to the condensed celestial bodies matter in the universe there is diffuse matter. It exists in the form of separated atoms and molecules, as well as in the form of giant clouds of gas and dust of various densities. All this, together with radiation, constitutes the boundless world ocean of liquefied matter, in which, as it were, celestial bodies float. Space bodies and systems are formed as a result of the condensation of nebulae that previously filled vast spaces. Consequently, cosmic bodies arise from the material environment as a result of the internal laws of motion of matter itself. Spirkin A.G. Philosophy: Textbook. - M.: Gardariki, 2002. S.245.
After material formations rose from the atomic level to a higher, molecular level, complication went on for several billion years. chemical substances. The gradual complication of molecules of carbon compounds led to the formation of organic compounds ( organic level). Gradually, more and more complex organic compounds were formed. Finally, there was life biological level).
Life was a necessary outcome of the development of the totality of chemical and geological processes on the surface of the Earth. Approximately two billion years ago, a gradual "spreading" of living things over the surface of the Earth began. The evolution of living things went from primitive, pre-cellular forms of protein existence to cellular organization, to the formation of first unicellular, and then multicellular organisms with an increasingly complex structure - invertebrates, vertebrates, mammals, primates. Finally, we see ourselves standing on the very last rung of the majestic ladder of progressive development ( social level). It is reasonable to assume that outside the earthly civilization there are giant space civilizations created by intelligent beings ( metasocial level).
The concept of structure is applicable not only to different levels of matter, but also to matter as a whole. The stability of the main structural forms of matter is due to the existence of a single structural organization of matter, which follows from the close interconnection of all currently known levels of structural organization.
Various structural formations of matter are not a random accumulation of unrelated particles, these are structural formations of different levels and degrees of complexity. Some of them, simpler and smaller, are components of others, larger and more complex, and precede their formation. Different types of particles are not only "elements" of the discrete organization of matter, but also "steps", "nodal points" of its development.
All levels of the organization of matter are characterized, firstly, by some general patterns, and secondly, by the connection, interaction of various levels. This connection is manifested, first of all, in the fact that simple forms of organization always accompany complex ones. For example, mechanistic motion occurs in thermal, electromagnetic, chemical, biological, and social phenomena. In turn, thermal, electromagnetic, chemical motion occurs in living organisms.
1. The concept of matter.
2. Properties of matter.
3. Structural organization of matter.
4. Levels of organization of natural knowledge.
Matter. The concept of "Matter" is ambiguous. It is used to refer to a particular fabric. Sometimes it is given an ironic meaning, speaking of "high matters." All objects and phenomena surrounding a person, despite their diversity, have a common feature: they all exist outside the consciousness of a person and independently of it, i.e. are material. People are constantly discovering more and more new properties of natural bodies, producing many things that do not exist in nature, therefore, matter is inexhaustible.
Matter is uncreated and indestructible, exists forever and is infinitely diverse in the form of its manifestations. The material world is one. All its parts - from inanimate objects to living beings, from celestial bodies to man as a member of society - are connected in one way or another. Those. all phenomena in the world are caused by natural material connections and interactions, causal relations and laws of nature. In this sense, there is nothing supernatural and opposing matter in the world. The human psyche and consciousness are also determined by the material processes taking place in the human brain, and are the highest form of reflection of the external world.
Matter Properties.
Consistency – characteristic material reality. The system is something that is connected in a certain way with each other and is subject to the corresponding law. Translated from Greek a system is a whole made up of parts, connection.
Systems can be objectively existing and theoretical or conceptual, i.e. existing only in the human mind. A system is an internal or external ordered set of interconnected and interacting elements. It captures the predominance of organization in the world over chaotic changes. All material objects of the universe have an internally ordered, systemic organization. Orderliness implies the presence of regular relations between the elements of the system, which manifests itself in the form of laws of structural organization. Structural organization, i.e. system, is a way of existence of matter.
Structural -this is the internal dismemberment of material existence. All natural systems that arise as a result of the interaction of bodies and the natural self-development of matter have internal orderliness, while external orderliness is characteristic of man-made artificial systems: technical, industrial, conceptual, informational, etc. The origins of the idea of the structural nature of the universe belong to ancient philosophy (atomistics of Democritus, Epicurus, Lucretius Cara).
The concept of the structure of matter covers macroscopic bodies, all cosmic systems. From this point of view, the concept of "structure" manifests itself in the fact that it exists in the form of an infinite variety of integral systems, closely interconnected, in the orderliness of the structure of each system. Such a structure is infinite in quantitative and qualitative terms. The manifestations of the structural infinity of matter are:
1) inexhaustibility of objects and processes of the microworld.
2) infinity of space and time.
3) infinity of changes and development of processes.
Only a finite area of the material world is empirically accessible to a person: on a scale from 10 -15 to 10 28 cm, and in time - up to 2 * 10 9 years.
Structural levels of matter organization. In modern natural science, this structuring of matter has taken shape in a scientifically substantiated concept of the systemic organization of the world. Structural levels of matter are formed from some type and are characterized by a special type of interaction between their constituent elements. The criteria for distinguishing different structural levels are the following features:
1) space-time scales;
2) a set of the most important properties and laws of change
3) the degree of relative complexity that arose in the process of the historical development of matter in a given area of the world.
The division of matter into structural levels is relative. In accessible spatio-temporal scales, the structure of matter manifests itself in its systemic organization, existence in the form of a multitude of hierarchically interacting systems from elementary particles to the Metagalaxy.
Each of the spheres of objective reality includes a number of interrelated structural levels. Within these levels, coordination relations are dominant, and between levels, subordinate ones.
Hierarchy of structural elements of matter. Modern physics gradually, step by step, opened up a completely new world of physical objects - microcosm or the world of microscopic particles, which are characterized by predominantly quantum properties. The behavior and properties of physical bodies, consisting of microparticles and constituting the macroworld, are described by classical physics. To two completely different objects - the microcosm and the macrocosm, one can add mega world - the world of stars, galaxies and the universe, located outside the earth.
Matter is distributed throughout the universe inhomogeneously. The structural elements of matter are combined into integral systems, the interactions within which are stronger and more important than the interactions of the elements of the system with its environment. In turn, material systems interact with each other, entering into relationships of subordination and forming a hierarchy of natural systems. The main steps in this hierarchy are microworld, macroworld and megaworld.
Objective reality consists of three main areas: inorganic nature, wildlife, society. For example, when classifying an inorganic type, elementary particles and fields, atomic nuclei, atoms, molecules, macroscopic bodies, and geological formations are distinguished.
Three structural levels can be distinguished:
1. megaworld – the world of space (planets, star complexes, galaxies, metagalaxies and unlimited scales up to 10 28 cm);
2. macroworld - the world of stable forms and dimensions commensurate with a person (as well as crystalline complexes of molecules, organisms, communities of organisms, i.e. macroscopic bodies 10 -6 - 10 7 cm);
3. microworld - the world of atoms and elementary particles, where the principle "consists of" is not applicable (the area is about 10 -15 cm).
When assessing the grandeur of the scale of the universe, the classic philosophical question always arises: is the universe finite or infinite? The concept of infinity is mainly used by mathematicians and philosophers. experimental physicists who experimental methods and measurement technology, always obtain the final values of the measured quantities. The great significance of science and, in particular, modern physics lies in the fact that by now many quantitative characteristics of objects have already been obtained not only in the macro- and microworld, but also in the mega-world.
The spatial scales of our Universe and the sizes of the main material formations, including micro-objects, can be represented from the following table, where the sizes are given in meters (for simplicity, only orders of numbers are given, i.e., approximate numbers within one order):
It can be seen from these data that the ratio of the largest to the smallest size available to today's experiment is 44 orders of magnitude. With the development of science, this attitude has constantly increased and will continue to grow as new knowledge about the material world around us is accumulated. Microworld is the Universe, considered on a scale so small that it is incommensurable with the size of the human body. The behavior of microscopic objects is determined mainly by quantum and thermal fluctuations (symmetry breaking).
Macroworld - this is the Universe, considered on a scale more or less commensurate with the size of the human body (from a living cell to a mountain). The behavior of macroscopic objects is well described by the laws of classical mechanics and electrodynamics.
Megaworld - this is the Universe, considered on a scale so large that it is incommensurable with the size of the human body. Gravitational interaction prevails in the megaworld. On its scale, the laws of the general theory of relativity become essential. The main structural elements of matter in the megaworld are galaxies and their collections. Galaxies are huge star systems made up of billions of stars. Each star belongs to some galaxy; There are no stars in intergalactic space.
At different structural levels of matter, we encounter special manifestations of spatio-temporal relations, with different types of motion. The microworld is described by the laws of quantum mechanics. The laws of classical mechanics operate in the macrocosm. Megaworld is associated with the laws of the theory of relativity and relativistic cosmology.
Different levels of matter are characterized different types connections:
1) on a scale of 10 -13 cm - strong interactions, the integrity of the nucleus is ensured by nuclear forces.
2) the integrity of atoms, molecules, macrobodies is provided by electromagnetic forces.
3) on a cosmic scale - by gravitational forces.
As the size increases, the interaction energy decreases. The smaller the dimensions of material systems, the more strongly their elements are interconnected.
Within each of the structural levels there are relationships subordination (the molecular level includes the atomic level, not vice versa). Any higher form arises on the basis of the lower one, includes it in a sublated form. This essentially means that the specificity of higher forms can be known only on the basis of the content of the higher form of matter in relation to it. The laws of new levels are not reducible to the laws of the levels on the basis of which they arose, and are leading for a given level of organization. In addition, the transfer of the properties of the higher levels of matter to the lower ones is unlawful. Each level of matter has its own qualitative specifics. In the highest level of matter, its lower forms are presented not in a pure form, but in a synthesized (removed) form.
Structural levels of matter interact with each other as part and whole. The interaction of the part and the whole lies in the fact that one presupposes the other, they are one, and cannot exist without each other. There is no whole without a part, and there are no parts without a whole. The part acquires its meaning only through the whole, just as the whole is the interaction of the parts. In the interaction of the part and the whole, the decisive role belongs to the whole. However, this does not mean that the parts are devoid of their specificity. The determining role of the whole presupposes not a passive, but an active role of the parts, aimed at ensuring the normal life of the universe as a whole. Subordinating to the general system of the whole, the parts retain their relative independence and autonomy. On the one hand, they act as components of the whole, and on the other hand, they themselves are a kind of integral structures, systems.
Organics as a type of material system also has several levels of its organization:
1) precellular level includes DNA, RNA, nucleic acids, proteins;
2) cellular - independently existing unicellular organisms;
3) multicellular - organs and tissues, functional systems (nervous, circulatory), organisms (plants and animals);
4) the organism as a whole;
5) populations (biotope) - communities of individuals of the same species that are connected by a common gene pool (they can interbreed and produce their own kind) a pack of wolves in a forest, a pack of fish in a lake, an anthill, a bush; biocenosis - a set of populations of organisms in which the waste products of some become the conditions for the life and existence of others inhabiting a land or water area. For example, in a forest, populations of plants living in it, as well as animals, fungi, lichens and microorganisms interact with each other, forming an integral system;
6) biosphere - a global system of life, that part of the geographic environment (lower part of the atmosphere, upper part of the lithosphere and hydrosphere), which is the habitat of living organisms, providing the conditions necessary for their survival (temperature, soil, etc.) formed as a result interactions of biocenoses.
The general basis of life at the biological level is organic metabolism (exchange of matter, energy, information with the environment), which manifests itself at any of the distinguished sublevels:
1) at the level of organisms, metabolism means assimilation and dissimilation through intracellular transformations;
2) at the level of biocenosis, it consists of a chain of transformations of a substance originally assimilated by producer organs through consumer organisms and destroyer organisms belonging to different species;
3) at the level of the biosphere, there is a global circulation of matter and energy with the direct participation of factors of a cosmic scale.
Within the biosphere, a special kind of material system begins to develop, which is formed due to the ability of special populations of living beings to work - the human community.
Social reality includes sublevels: individual, family, group, collective, social group, classes, nations, state, system of states, society as a whole. Society exists only thanks to the activity of people. The structural level of social reality is in ambiguous linear relationships with each other (for example, the level of the nation and the level of the state). The interweaving of different levels of the structure of society does not mean the absence of order and structure in society. In society, one can single out fundamental structures - the main spheres of public life: material and production, social, political, spiritual, etc., which have their own laws and structures. All of them in a certain sense are subordinated, structured and determine the genetic unity of society as a whole. Thus, any of the areas of objective reality is formed from a number of specific structural levels that are in strict order within a particular area of reality. The transition from one area to another is associated with the complication and increase in the set of formed factors that ensure the integrity of systems, i.e. the evolution of material systems proceeds in the direction from simple to complex, from lower to higher.
Structural levels of matter.
Levels of organization of natural knowledge. Our knowledge about nature accumulates and develops not randomly, but in a strict sequence, determined by the hierarchy of levels of matter organization. Nature is inherently one and the division of knowledge about it into separate natural disciplines, for example, chemistry or physics, is often quite arbitrary: physical ideas are reflected in the explanation of chemical processes, and the study of chemical transformations of substances into each other leads physicists to discover new physical laws and phenomena, such as the discovery of high-temperature superconductivity or the discovery solitons .
This is due, first of all, to the existence of a common object of study for chemists and physicists - substances. But there are significant differences between these two sciences: firstly, the range of objects of study of physics is wider than that of chemistry - from the microcosm to the scale of the Universe; secondly, the laws of physics are more universal and applicable to a whole range of natural phenomena. This is evidenced by the development of a large number of related sciences - physical chemistry, geophysics, biophysics, astrophysics etc. In these sciences, scientists try to explain chemical, biological and all other natural phenomena and processes in terms of basic physical laws.
Describe the phenomena and processes of nature phenomenological sciences . The purpose of such knowledge is to describe natural phenomena at the macroscopic level, i.e. at a level accessible to the human senses. However, modern experimental science, using a variety of research methods and the latest equipment: electron microscopes, NMR tomographs, high-resolution spectroscopic equipment, including X-ray spectral and others modern methods research, allows you to significantly delve into the subject under study - to descend from the macro level to microlevels .
There is a certain hierarchy of knowledge, when complex phenomena and processes are described from the point of view of simpler and more familiar ones. Recall once again the scheme of connections of physical, chemical and biological sciences already known to you:
PHYSICS ---> CHEMISTRY ----> BIOLOGY
But this connection is not a purely mechanical scheme invented by someone, it reflects the hierarchy of the organization of matter that really exists in nature:
ELEMENTARY PARTICLES ---> ATOM --> MOLECULE ->
MACROMOLECULE --> SUPRAMOLECULAR COMPLEXES -->
CELL ORGANELLES -----> LIVING CELL
At present, it is customary to divide the single Nature for convenience into three structural levels – micro-, macro- and mega-world. The natural, although partly subjective, signs of division are the sizes and masses of the objects under study.
Microworld– the world of extremely small, not directly observable microsystems with a characteristic size of 10–8 cm or less (atoms, atomic nuclei, elementary particles).
Macroworld- the world of macrobodies, ranging from macromolecules (sizes from 10 -6 cm and above) to objects whose dimensions are comparable with the scale of direct human experience - millimeters, centimeters, kilometers, up to the size of the Earth (the length of the Earth's equator is ~ 10 9 cm).
Megaworld- the world of objects on a cosmic scale from 10 9 cm to 10 28 cm. This range includes the sizes of the Earth, the Solar System, the Galaxy, the Metagalaxy.
Although the micro-, macro- and mega-world are closely interconnected and form a single whole, nevertheless, at each of these structural levels, their own specific laws operate: in the micro-world - the laws of quantum physics, in the macro-world - the laws of classical natural science, primarily classical physics: mechanics, thermodynamics, electrodynamics. The laws of the megaworld are based primarily on the general theory of relativity.
Microworld
Atomic physics.Even the ancient Greeks Leucippus and Democritus put forward a brilliant conjecture that matter consists of the smallest particles - atoms.
Scientific Foundations atomic and molecular doctrines were laid down much later in the works of the Russian scientist M.V. Lomonosov, French chemists L. Lavoisier and J. Proust, English chemist J. Dalton, Italian physicist BUT. Avogadro and other researchers.
Periodic law D.I. Mendeleev showed the existence of a regular relationship between all chemical elements. It became clear that the basis of all atoms is something in common. Until the end of the XIX century. Chemistry was dominated by the belief that the atom is the smallest indivisible particle a simple substance. It was believed that during all chemical transformations, only molecules are destroyed and created, while atoms remain unchanged and cannot be divided into parts. And finally, at the end of the XIX century. discoveries were made that showed the complexity of the structure of the atom and the possibility of transforming some atoms into others.
German scientists were the first to point out the complex structure of the atom G.R. Kirchhoff and R.V. Bunsen by studying the emission and absorption spectra various substances. The complex structure of the atom was also confirmed by experiments on the study of ionization, the discovery and study of the so-called cathode rays, and the phenomena of radioactivity.
G.R. Kirchhoff and R.V. Bunsen found that each chemical element corresponds to a characteristic set of spectral lines inherent only to it in the emission and absorption spectra. This meant that light is emitted and absorbed by individual atoms, and the atom, in turn, is complex system capable of interacting with an electromagnetic field.
This was also evidenced by the phenomenon of ionization of atoms, discovered in studies of electrolysis and gas discharge. This phenomenon could be explained only by assuming that the atom in the process of ionization loses some of its charges or acquires new ones.
Evidence of the complex structure of the atom was the experiments on the study of cathode rays arising from an electric discharge in highly rarefied gases. To observe these rays, as much air as possible is pumped out of a glass tube into which two metal electrodes are soldered, and then a high voltage current is passed through it. Under such conditions, "invisible" cathode rays propagate from the cathode of the tube perpendicular to its surface, causing a bright green glow in the place where they fall. Cathode rays have the ability to set in motion easily mobile bodies and deviate from their original path in magnetic and electric fields.
The study of the properties of cathode rays led to the conclusion that they consist of tiny particles that carry a negative charge. Later it was possible to determine the mass and magnitude of their charge. It turned out that the mass of the particles and the magnitude of their charge do not depend either on the nature of the gas remaining in the tube, or on the substance from which the electrodes are made, or on other conditions of the experiment. Moreover, cathodic particles are known only in a charged state and cannot exist without their charges, cannot be transformed into electrically neutral particles: the electric charge is the very essence of their nature. These particles are called electrons.
In cathode tubes, electrons are separated from the cathode under the influence of an electric field. But they can also arise without any connection with the electric field. So, for example, during electron emission, metals emit electrons; during the photoelectric effect, many substances also emit electrons. The release of electrons by a wide variety of substances indicated that these particles are part of all atoms without exception. This led to the conclusion that atoms are complex formations built from smaller components.
In 1896, while studying the luminescence of various substances, A.A. becquerel accidentally discovered that uranium salts radiate without prior illumination. This radiation, which has great penetrating power and affects a photographic plate wrapped in black paper, was called radioactive radiation. Later it was found that it consists of heavy positively charged α-particles, light negative β-particles (electrons) and electrically neutral γ-radiation.
The discovery of the electron can be considered the beginning of the birth of atomic physics, which led to attempts to build atom models. Since the electron has a negative charge, and the atom as a whole is stable and electrically neutral, it was natural to assume the presence of positively charged particles in the atom.
The first models of the atom based on the concepts of classical mechanics and electrodynamics appeared in 1904: the Japanese physicist became the author of one of them. Hantaro Nagaoka, the other belonged to the English physicist J. Thomson- the author of the discovery of the electron.
X. Nagaoka presented the structure of the atom similar to the structure of the solar system: the role of the Sun is played by the positively charged central part of the atom, around which "planets" - electrons - move along established ring-shaped orbits. At small displacements, electrons excite electromagnetic waves.
In J. Thomson's model of the atom, positive electricity is "distributed" over a sphere in which electrons are interspersed. In the simplest hydrogen atom, the electron is at the center of a positively charged sphere. In multi-electron atoms, electrons are arranged in stable configurations calculated by J. Thomson. Thomson believed that each configuration determines certain Chemical properties atoms. He made an attempt to theoretically explain the periodic system of elements of D. I. Mendeleev.
But it soon turned out that new experimental facts refute Thomson's model and, conversely, testify in favor of the planetary model. These facts have been established E. Rutherford in 1912. First of all, it should be noted his discovery of the atomic nucleus. To reveal the structure of the atom, Rutherford probed the atom with the help of α-particles, which arise from the decay of radium and some other radioactive elements. Their mass is about 8000 times the mass of the electron, and the positive charge is equal in modulus to twice the charge of the electron.
In Rutherford's experiments, a beam of α-particles fell on a thin foil of the material under study (gold, copper, etc.). After passing through the foil, the α-particles hit a screen coated with zinc sulfide. The collision of each particle with the screen was accompanied by scintillation(flash of light) that could be observed. In the absence of foil, a bright circle appeared on the screen, consisting of scintillations caused by the particle beam. But when a foil was placed in the path of the beam, then, contrary to expectations, the α-particles experienced very little scattering on the atoms of the foil and were distributed on the screen inside a circle of a slightly larger area.
It also turned out to be completely unexpected that a small number of α-particles (about one in twenty thousand) deviated through angles greater than 90°, i.e. almost returned. Rutherford realized that a positively charged α-particle could be thrown back only if, in the target atoms, the positive charge of the atom and its mass are concentrated in a very small region of space. So Rutherford came up with the idea atomic nucleus- a body of small size, in which almost all the mass and all the positive charge of the atom are concentrated.
By counting the number of α-particles scattered at large angles, Rutherford was able to estimate the size of the nucleus. It turned out that the nucleus has a diameter of the order
10–12–10–13 cm (for different nuclei). The size of the atom itself is approximately 10–8 cm, i.e. 10 - 100 thousand times the size of the nucleus. Subsequently, it was possible to accurately determine the charge of the nucleus. If we take the charge of an electron as unity, then the charge of the nucleus turned out to be exactly equal to the number of a given chemical element in periodic system elements D.I. Mendeleev.
The planetary model of the atom with a positively charged atomic nucleus followed directly from Rutherford's experiments. Given that the atom as a whole must be electrically neutral, it was necessary to conclude that the number of intraatomic electrons, as well as the charge of the nucleus, is equal to the ordinal number of the element in the periodic system. It is also obvious that the electrons inside the atom cannot be at rest, since they would fall on it due to attraction by the positive nucleus. Therefore, they must move around the core like the planets around the Sun. This character of electron motion is determined by the action of electric Coulomb forces from the nucleus.
In a hydrogen atom, only one electron revolves around the nucleus. The nucleus of a hydrogen atom has a positive charge, equal in absolute value to the charge of an electron, and a mass approximately 1836 times greater than the mass of an electron. This nucleus was named by Rutherford proton and began to be regarded as an elementary particle.
The size of an atom is determined by the radius of the orbit of its electrons. The fairly illustrative planetary model of the atom, as already mentioned, is a direct consequence of Rutherford's experimental results on the scattering of α-particles by the atoms of matter.
However, it soon became clear that this simple model contradicts the laws of electrodynamics, from which it follows that the Rutherford model of the atom is an unstable system and for a long time an atom of this design cannot exist. The fact is that the movement of electrons in circular orbits occurs with acceleration, and an accelerated charge, according to the laws of Maxwell's electrodynamics, must radiate electromagnetic waves (ω - a frequency equal to the frequency of its circulation around the nucleus). Radiation is accompanied by a loss of energy. Losing energy, the electrons must approach the core, just as a satellite approaches the Earth when braking in the upper atmosphere.
In reality, however, this does not happen. Atoms are stable, they can exist indefinitely without radiating electromagnetic waves at all.
The way out of this situation was found by the Danish scientist N. Bor. He made a radical conclusion that the laws of classical mechanics and electrodynamics are generally not applicable in the microcosm and, in particular, in the atom. Nevertheless, in order to preserve Rutherford's planetary model of the atom, he formulated two postulates (Bohr's postulates) that run counter to both classical mechanics and classical electrodynamics. These postulates laid the foundations for fundamentally new theories of the microworld - quantum mechanics and quantum electrodynamics ( quantum theory electromagnetic field). Justifying his postulates, Bohr relied on the idea of the existence of electromagnetic field quanta, put forward in 1900 by M. Planck and then developed by A. Einstein (to explain the photoelectric effect).
Bohr's postulates are as follows: an electron can move around the nucleus not in any orbits, but only in those that satisfy certain conditions arising from quantum theory. These orbits are called sustainable, or quantum, orbits. When an electron moves along one of the stable orbits possible for it, it does not radiate. The transition of an electron from a distant orbit to a closer orbit is accompanied by a loss of energy.
The energy lost by an atom during each transition is converted into one quantum of radiant energy. The frequency of the light emitted in this case is determined by the radii of the two orbits between which the transition of the electron takes place. The greater the distance from the orbit in which the electron is located to the orbit to which it passes, the greater the frequency of the radiation.
The simplest of the atoms is the hydrogen atom: only one electron revolves around the nucleus. Based on the above postulates, Bohr calculated the radii of possible orbits for this electron and found that they are related as squares natural numbers: 1:2: : 3: ... : P. Value P was named principal quantum number. The radius of the orbit closest to the nucleus in the hydrogen atom is 0.53 angstroms. The frequencies of the radiations calculated from this, accompanying the transitions of an electron from one orbit to another, turned out to be exactly the same as the frequencies found experimentally for the lines of the hydrogen spectrum. Thus, the correctness of the calculation of stable (stationary) orbits for the hydrogen atom was proved, along with the applicability of Bohr's postulates for such calculations.
Subsequently, Bohr's theory was extended to the atomic structure of other elements. However, the extension of the theory to many-electron atoms and molecules encountered difficulties. The more detailed the theorists tried to describe the motion of electrons in a multielectron atom, to determine their orbits, the greater were the discrepancies between the results and experimental data. In the course of the development of quantum theory, it became clear that these discrepancies are of a fundamental nature and are associated with the so-called wave properties of the electron.
The fact is that in 1924 Louis de Broglie extended the well-known by that time corpuscular-wave dualism of the electromagnetic field to the real particles of the microworld (atoms, electrons, protons, etc.). Recall that, according to his idea, particles that have mass, charge, etc. also have wave properties. In this case, the de Broglie wavelength (λ) is related to the particle momentum R and equal to
λ = h/p, where h is Planck's constant.
De Broglie's idea found a brilliant confirmation in the experiments of K. Davisson and L. Germer (1927), in which the phenomenon of electron diffraction was observed – a classic example of a wave phenomenon.
Developing the wave ideas of particles of the microworld, E. Schrödinger created a mathematical wave model of the atom in the form of the now famous Schrödinger wave differential equation:
An analysis of the Schrödinger wave equation showed that it can be used to determine all possible discrete energies E p in the atom. In addition, it was found that the wave function does not allow absolutely accurate determination of the position of electrons in atoms, they spread into a kind of “cloud”; thus, we can only speak about the probability of finding electrons in one place or another of the atom, which is characterized by the square of the wave amplitude.
Taking into account the laws of quantum wave mechanics, it becomes clear why it turned out to be impossible to accurately describe the structure of an atom on the basis of ideas about the Bohr orbits of electrons in an atom. Such precisely localized orbits in atoms simply do not exist, and the good agreement between the calculation of the orbits of electrons in the hydrogen atom, in accordance with the Bohr theory and experimental data, is due to the fact that only for the hydrogen atom, the Bohr electron orbits coincided well with the curves of the average charge density calculated in accordance with the quantum theory of Schrödinger. Such a coincidence is not observed for many-electron atoms.
At present, based on quantum mechanics, as well as quantum electrodynamics - the quantum theory of the electromagnetic field, developed in 1927. P.A. Dirac, succeeded in explaining many features of the behavior of many-electron atomic-molecular systems. In particular, it was possible to resolve the most important question about the structure of atoms of various elements and to establish the dependence of the properties of elements on the structure of the electron shells of their atoms. At present, schemes of the structure of atoms of all chemical elements have been developed, which make it possible to explain many of the physical and chemical properties of elements.
Recall that the number of electrons revolving around the nucleus of an atom corresponds to the serial number of the element in the periodic system of D.I. Mendeleev. The electrons are arranged in layers. Each layer has a certain number of electrons that fill or, as it were, saturate it. Electrons of the same layer are characterized by close energy values, i.e. are about the same energy level. The entire shell of an atom breaks down into several energy levels ( n). The electrons of each subsequent layer are at a higher energy level than the electrons of the previous layer. The maximum number of electrons ( N) that can be at a given energy level (n) is determined by the formula N = 2n 2 , i.e. at the first level (n=1) there can be two electrons, on the second (n=2)- eight electrons, on the third (n=3)- eighteen.
The electrons of the outer layer, as the most distant from the nucleus and, therefore, the least firmly connected with the nucleus, can break away from the atom and join other atoms, entering into the composition of the outer layer of the latter. Atoms that have lost one or more electrons become positively charged, since the charge of the atom's nucleus exceeds the sum of the charges of the remaining electrons. Conversely, atoms that have attached electrons become negatively charged. The resulting charged particles are called ions. Many ions, in turn, can lose or gain electrons, while turning into electrically neutral atoms or new ions with a different charge.
Summing up the consideration of the main results of quantum mechanical approaches to the structure and structure of atoms, we note the following . The state of each electron in an atom is characterized by four quantum numbers - n, l, t, s:
1) n – the main thing quantum number characterizes the energy of an electron in the corresponding orbit ( n);
2)l – orbital quantum number characterizes the shape of the orbit (electron cloud) and can vary in the atom from 0 to n = 1;
3)t– magnetic quantum number characterizes the orientation of orbits (electron clouds) in space and can take values from +1 to -1;
4)s–spin quantum number characterizes the rotation of an electron around its own axis and can take only two values: s= ±1/2.
According to one of the most important principles of quantum mechanics, the Pauli principle, an atom cannot have electrons in which all four quantum numbers are the same. Within the framework of quantum mechanics, both the structure of atoms and the change in the properties of chemical elements in the periodic system of D.I. Mendeleev.
The application of quantum mechanics to physical fields also turned out to be fruitful. A quantum theory of the electromagnetic field was built - quantum electrodynamics, which revealed a number of fundamental laws of the microworld. Among them are the most important laws of the mutual transformation of two types of material substances - material and field matter - into each other.
It took its place in the series of elementary particles photon- a particle of an electromagnetic field that does not have a rest mass. The synthesis of quantum mechanics and special relativity led to the prediction of the existence antiparticles. It turned out that each particle should have, as it were, its own "double" – another particle with the same mass but opposite electric or some other charge. English physicist P.A. Dirac – founder of the relativistic to pant field theory – predicted the existence of the positron and the possibility of the conversion of a photon into an electron-positron pair and vice versa. The positron, the antiparticle of the electron, was experimentally discovered in 1934. K.D. Anderson in cosmic rays.
Nuclear physics.According to modern concepts, the atomic nuclei of elements consist of protons and neutrons. The first indications that the composition of nuclei also includes protons (the nuclei of hydrogen atoms) were obtained by Rutherford in 1919 as a result of his new (after the discovery of the structure of the atom) sensational discovery - the splitting of the atomic nucleus under the action of α-particles and the production of new chemical elements in the result of the first artificial nuclear reaction.
In one of the variants of his experiments using a cloud chamber filled with nitrogen, inside which there was a radioactive source of radiation, Rutherford obtained photographs of tracks of α-particles, at the end of which there was a characteristic branching - a "fork". One side of the "fork" gave a short track, and the other - a long one. The long track had the same features as the tracks observed earlier by Rutherford during the bombardment of hydrogen atoms with α-particles.
Thus, for the first time, the idea was expressed that hydrogen nuclei are an integral part of the nuclei of other atoms. Subsequently, Rutherford proposed the term "proton" for this constituent part of the nucleus.
The Rutherford reaction scheme can be represented as follows: the α-particle enters the atomic nucleus of nitrogen and is absorbed by it. The resulting intermediate nucleus of the fluorine isotope is unstable: it ejects one proton from itself, turning into the nucleus of the oxygen isotope.
In 1932 D.D. Ivanenko published a note in which he suggested that, along with the proton, the neutron is also a structural element of the nucleus. In 1933, he substantiated the proton-neutron model of the nucleus and formulated the main thesis, which is that there are only heavy particles in the nucleus - protons and neutrons. In this case, both particles can turn into each other. Further proton and neutron began to be considered as two states of one particle - nucleon.
And in the same 1933 J. Chadwick experimentally proved the existence of neutrons in atomic nuclei. He irradiated a beryllium plate with α-particles and studied the reaction of the transformation of beryllium (Be) into carbon (C) with the emission of a neutron n).
The neutrons emitted from beryllium were sent to a cloud chamber filled with nitrogen (N), and when a neutron hit and a proton of a nitrogen atom, a boron nucleus (B) and α-particles were formed.
The neutron itself does not give a track in the cloud chamber, but from the tracks of the boron nucleus and the α-particle, it can be calculated that this reaction is caused by a neutral particle with a mass of one atomic mass unit, i.e. neutron. Note that a free neutron does not exist for long, it is radioactive, its half-life is about 8 minutes, after which it turns into a proton, emitting a β-particle (electron) and a neutrino. After the discovery of the neutron, the proton-neutron model of the structure of atomic nuclei D.D. Ivanenko has become universally recognized.
All nuclear reactions are accompanied by the emission of certain elementary particles. The products of nuclear reactions are radioactive, they are called artificially radioactive isotopes. The phenomenon of artificial radioactivity was discovered in 1934 by famous French physicists Frederick and Irene Joliot-Curie.
Like naturally radioactive substances, artificially produced radioactive isotopes emit known α, β, and γ radiations. But in addition to the above radiations, Frederic and Irene Joliot-Curie discovered a new type of radioactivity - the emission of positive electron-positrons.
For the first time, this was established using a cloud chamber when bombarding some light elements (beryllium, boron, aluminum) with α-particles, as a result of which a number of new radioactive isotopes were artificially created that were not previously observed in nature. An example of the formation of a positron radioactive isotope is the bombardment of aluminum with α-particles. And in this case, the aluminum nucleus emits a neutron and turns into the nucleus of a radioactive isotope of phosphorus, which in turn, emitting a positron β + , turns into a stable isotope of silicon.
On an industrial scale, artificial radioactive isotopes are usually obtained by irradiating (mainly neutron) the corresponding chemical elements in nuclear reactors.
After it was established that the nuclei of atoms consist of both protons and neutrons, the theory of the atomic nucleus was further developed in the direction of studying the interactions of particles inside the nucleus, as well as the structure of the atomic nuclei of various elements.
Below are basic information about the properties and structure of nuclei.
1. core called the central part of the atom, in which almost all the mass of the atom and its positive electric charge are concentrated. All atomic nuclei are made up of protons and neutrons, which are considered to be two charge states of a single particle, the nucleon.
Proton has a positive electric charge equal in absolute value to the charge of an electron e\u003d 1.6 -19 C and rest mass t p ~ 1.6726 10 - 27 kg.
Neutron has no electric charge, its mass is slightly larger than the mass of a proton - t p= 1.6749 10 -27 kg.
The mass of nuclei of elementary particles is usually expressed in atomic mass units (amu). The atomic mass unit is 1/12 of the mass of the carbon isotope: 1 a.m.u. = 1.66 10 -27 kg. Hence, t r= 1.00728 amu, and t p= 1.00866 amu
2. The charge of the nucleus is called the quantity Ze, where e is the value of the proton charge; Z is the ordinal number of a chemical element in the periodic system of Mendeleev, equal to the number of protons in the nucleus.
At present, nuclei with serial numbers Z = 1 to Z = 114 are known. For light nuclei, the ratio of the number of neutrons (N) to the number of protons (Z) close to or equal to one. For the nuclei of chemical elements located at the end of the periodic system, the ratio N/Z = 1.6.
3. Total number of nucleons in the nucleus BUT= N+ Z called mass number. Nucleons (proton and neutron) are assigned a mass number equal to one. nuclei with the same Z, but different BUT called isotopes. Kernels, which, at the same BUT have different Z are called isobars. The nuclei of chemical elements are usually denoted by the symbol .X, A, Z where X- symbol of a chemical element; BUT– mass number; Z is the atomic number.
In total, about 300 stable isotopes of chemical elements and more than 2000 natural and artificially obtained radioactive isotopes are known.
All isotopes of one chemical element have the same structure of electron shells. Therefore, all isotopes of a given element have the same chemical properties. It has now been established that most of the chemical elements found in nature are a mixture of isotopes. Therefore, the atomic masses of the elements indicated in the periodic table often differ significantly from integers.
4. The size of the nucleus is characterized by the radius of the nucleus, which has a conditional meaning due to the blurring of the boundaries of the nucleus. Empirical formula for core radius R= R A, where R=(1.3/1.7)10 -15 m, can be interpreted as the proportionality of the volume of the nucleus to the number of nucleons in it.
5. Nuclear particles have their own magnetic moments, which determine the magnetic moment of the nucleus (R tt) generally. The unit for measuring the magnetic moments of nuclei is nuclear magneton μ I = eh,/2m p, where e is the absolute value of the electron charge; h is Planck's constant; t r is the mass of the proton. nuclear magneton μ poison 1836.5 times less magnetic moment electron in an atom, from which it follows that the magnetic properties of atoms are determined by magnetic properties its electrons.
6. The distribution of the electric charge of protons over the nucleus is generally asymmetric. The measure of deviation of this spherically symmetric distribution is quadrupole electric moment of the nucleus Q. If the core density is assumed to be the same everywhere, then Q determined only by the shape of the nucleus.
The nucleons that make up the nucleus are interconnected by special forces of attraction - nuclear forces. The stability of the atomic nuclei of most elements indicates that the nuclear forces are exceptionally large: they must exceed the significant Coulomb repulsive forces acting between protons located at distances of the order of 10–13 cm (on the order of the size of the nucleus). Nuclear forces - forces of a special kind associated with the existence inside the nucleus of a special type of matter - nuclear field.
At present, the meson theory of nuclear forces is accepted, according to which nucleons interact with each other by exchanging special elementary particles - π mesons - quanta of the nuclear field.
The presence of exchange particles in the nucleus - mesons - was first theoretically predicted by a Japanese scientist Hidoki Yukavoy in 1936, and then discovered in cosmic rays in 1947.
General characteristics of nuclear forces comes down to the following.
1. Nuclear forces are short-range forces. They appear only at very small distances between the nucleons of the nucleus of the order of 10 - 15 m. The length (1.5 ÷ 2.2) -10 - 15 m is called range of nuclear forces.
2. Nuclear forces exhibit charge independence: the attraction between two nucleons is the same regardless of the charge state of the nucleons - proton or nucleon. The charge independence of nuclear forces can be seen from a comparison of the energies in mirror nuclei (the so-called nuclei in which the total number of nucleons is the same, but the number of protons in one is equal to the number of neutrons in the other).
3. Nuclear forces have the property of saturation, which manifests itself in the fact that the nucleon in the nucleus interacts only with a limited number of neighboring nucleons closest to it. That is why there is a linear dependence of the binding energies of nuclei on their mass numbers BUT. Almost complete saturation of nuclear forces is achieved in the α-particle, which is a very stable formation.
Nucleons are firmly bound in the nucleus by nuclear forces. To break this connection, i.e. for the complete separation of nucleons, it is necessary to do a significant amount of work. The energy required to separate the nucleons that make up the nucleus is called the binding energy of the nucleus. The value of the binding energy can be determined on the basis of the law of conservation of energy and the law of proportionality of mass and energy in accordance with the Einstein formula E \u003d ts 2.
According to the law of conservation of energy, the energy of nucleons bound in the nucleus must be less than the energy of separated nucleons by the value of the binding energy ε 0 . On the other hand, according to the law of proportionality of mass and energy, the change in the energy of the system ∆W must be accompanied by a proportional change in the mass of the system by ∆m, those. ∆W = ∆mc 2 , where with is the speed of light in vacuum.
Since in this case ∆W is the binding energy of the nucleus, then the mass of the atomic nucleus must be less than the sum of the masses of the nucleons that make up the nucleus by the value ∆m, which is called nuclear mass defect. From the relation ∆W = ∆mc 2 it is possible to calculate the binding energy of a nucleus if the mass defect of this nucleus is known Δm.
As an example, let us calculate the binding energy of the nucleus of a helium atom. It consists of two protons and two neutrons. proton mass t r= 1.0073 amu, neutron mass - t p= 1.0087 amu Therefore, the mass of nucleons forming a nucleus is equal to 2t p + 2t p = 4.0320 amu The mass of the nucleus of a helium atom t i = 4.0016 amu Thus, the mass defect of the helium atomic nucleus is equal to ∆m= 4.0320 - 4.0016 = 0.03 amu, or ∆m = 0.03 1.66 10~ 27 = 5 10~ 29 kg. Then the binding energy of the helium nucleus
∆W = ∆mc 2\u003d 510-29 9-10 16 J \u003d 28 MeV.
The general formula for calculating the binding energy of any nucleus (in joules) will be:
ΔW \u003d c 2 (- t i),
where Z is the atomic number; BUT - mass number.
The binding energy of a nucleus per nucleon is called specific binding energy (ε ). Therefore, ε= ΔW/A(specific binding energy) characterizes the stability of atomic nuclei. The larger s, the more stable the core.
On fig. 1 shows the results of calculations of specific binding energies for different atoms (depending on the mass numbers BUT).
From the graph in Fig. 2.2 it follows that the specific binding energy is maximum (8.65 MeV) for nuclei with mass numbers of the order of 100. For heavy and light nuclei, it is slightly less (for example, 7.5 MeV for uranium and 7 MeV for helium), for the atomic nucleus of hydrogen the specific binding energy is zero, which is quite understandable, because there is nothing to dissociate in this nucleus: it consists of only one nucleon (proton).
a.u.m.
Rice. 1. Dependence of specific binding energies on mass numbers
Any nuclear reaction is accompanied by the release or absorption of energy. In the fission of heavy nuclei with mass numbers BUT about 100 (or more) nuclear energy is released.
The release of nuclear energy also occurs in nuclear reactions of the type - when several light nuclei are combined (synthesis) into one nucleus. Thus, the release of nuclear energy occurs both in the fission reactions of heavy nuclei and in the reactions of fusion of light nuclei. Amount of nuclear energy Δ ε released by each reacted nucleus is equal to the difference between the binding energy ε of the reaction product and the binding energy of the original nuclear material.
Ratio ∆E∆t>ħ/2 means that the energy conversion with accuracy ∆E should take a time interval equal to at least ∆t~ ħ/∆E. This relation is responsible for the natural width of the spectral lines of atoms and ions. The lifetime of the excited state of atoms is of the order t~10 -8 ÷10 -9 s. Therefore, the energy uncertainty of such states is ∆E~ ħ/t, which corresponds to the natural width of the spectral lines. If the energy uncertainty ∆Е ~ ħ/∆t corresponds to the energy of some particle ( mс 2 , hv), to this particle, having arisen from "nothing", can be in a virtual state of time ∆t without violating the law of conservation of energy. In modern quantum field theory, the interaction of particles and their mutual transformations are considered as the birth or absorption of each real particle virtual particles. Any particle continuously emits or absorbs virtual particles of different types. So, for example, electromagnetic interaction is the result of the exchange virtual photons, gravitational - gravitons. The field of nuclear forces is determined virtual π–mesons. The weak interaction is created vector bosons(discovered in 1983 at CERN, Switzerland-France). And the carrier of the strong interaction is gluons(from the English word meaning "glue"). The uncertainty relation limits the applicability of classical mechanics to micro-objects. It caused numerous philosophical discussions. The coordinates of the particle and its momentum, the change in energy and the time during which this change occurred are called mutually complementary quantities. Obtaining experimental information about some physical quantities that describe a microparticle is inevitably associated with the loss of information about other quantities that are additional to the first ones. This statement, first formulated by the Danish physicist N. Bohr, is called the principle of complementarity. Bohr explained the complementarity principle by the influence of a measuring instrument, which is always a macroscopic instrument, on the state of a microobject. However, from the standpoint of modern quantum theory, states in which mutually complementary quantities would simultaneously have precisely defined values are fundamentally impossible. The principle of complementarity reflects the objective properties of quantum systems that are not related to the existence of an observer, and the role of the measuring instrument is to "prepare" a certain state of the system. Any new theory that claims to be a deeper description of physical reality and a wider scope than the old one must include the previous one as a limiting case. So relativistic mechanics (special relativity) in the limit of low velocities passes into Newtonian. In quantum mechanics conformity principle requires the coincidence of its physical consequences in the limiting case with the results of the classical theory. The principle of correspondence reveals the fact that quantum effects are significant only when considering micro-objects, when the dimensions of the action are comparable with Planck's constant. From a formal point of view, the correspondence principle means that, in the limit ħ → 0 the quantum mechanical description of physical objects should be equivalent to the classical one. The significance of the correspondence principle goes beyond quantum mechanics– it will become an integral part of any new theoretical scheme. In modern physics, the term "elementary particles" is usually used not in its exact meaning, but less strictly - to name a large group of the smallest particles of matter that are not atoms or atomic nuclei (the proton is an exception). The most important property of all elementary particles is the ability to be born and destroyed (emitted and absorbed) when interacting with other particles. Now the total number of elementary particles known to science (together with antiparticles) is approaching 400. Some of them are stable and exist in nature in a free or loosely bound state. These are electrons, protons, neutrons, photons and various kinds of neutrinos.
All other elementary particles are extremely unstable and are formed in secondary cosmic rays or are obtained in the laboratory. The main method of their generation is the collision of fast stable particles, during which part of the initial kinetic energy is converted into the rest energy of the formed particles (usually not coinciding with the colliding ones).
The general characteristics of all elementary particles are the mass m, lifetime t, spin J and electric charge Q.
Depending on the lifetime, elementary particles are divided into stable, quasi-stable and unstable (resonances). The electron (t > 5 10 21 years), proton (t > 5 10 31 years), photon and neutrino are stable within the accuracy of modern measurements. Quasi-stable particles include particles that decay due to electromagnetic and weak interactions, their lifetimes t > 5 10 -20 s. An example of a quasi-stable particle is the neutron.
It decays due to the weak interaction, the average lifetime is 15.3 minutes: 
.
Resonances are called elementary particles that decay due to strong interaction; their characteristic lifetimes are t~ 10 -22 - 10 -24 s.
Electric charges of elementary particles are integer multiples of e≈1.6-10 -19 C, called the elementary electric charge (electron charge). Known elementary particles have Q= 0, ±1, ±2.
The spin of elementary particles is an integer or half-integer multiple of Planck's constant ħ.
Particles with half-integer spin are called fermions. Fermions are leptons (e.g. electron and neutrino) and baryons, consisting of quarks (for example, proton and neutron). Fermion systems are described Fermi-Dirac quantum statistics. Fermions obey the Pauli exclusion principle and in a given quantum state of a system of fermions it cannot, there is more than one particle. Fermions form material structures.
Particles with integer or zero spin are called bosons. Bosons include particles with zero rest mass (photon, graviton), as well as mesons, consisting of quarks (for example, π mesons). Systems of such particles are described Bose-Einstein statistics. Bosons do not obey the Pauli exclusion principle and there is no restriction on the number of particles that can be in a certain quantum state. They form an interaction field (according to quantum field theory) between fermions.
So, for example, material structures are formed by electrons and nucleons (protons and neutrons that form the nuclei of atoms), and the electromagnetic field of interaction between them is formed by photons (more precisely, virtual photons) (Fig. 2).
Fig.2.Classification of elementary particles
Mesons and baryons are made up of quarks, and therefore have a common name - hadrons. All known hadrons consist of either a quark-antiquark pair (mesons) or three quarks (baryons). Quarks and antiquarks are kept inside the hadrons by the gluon field. Quarks differ in "flavor" and "color". Each quark can be in one of three color states: "red", "blue" and "yellow". As for the "flavors", there are 5 of them known and the presence of the sixth is assumed. Quark flavors are denoted by letters u, d, s, c, b, t, that match English words up, down, strange, charmed, beaty and truth. Moreover, each quark corresponds to its antiquark. Not a single quark has ever been registered in free form, despite years of searching. Quarks can only be observed inside hadrons.
Physics of elementary particles is based on the concept of fundamental interactions - gravitational, electromagnetic, strong and weak.
The electromagnetic interaction is due to the exchange of photons, which are better studied than other bosons. The source of photons is an electric charge. Gravitational interaction is associated with so far hypothetical particles - gravitons. Neutral (Z 0) and charged (W + ,W –) bosons are carriers of the weak interaction between electrons, protons, neutrons and neutrinos. The carriers of the strong interaction are gluons . They kind of stick together quarks in hadrons. The sources of gluons are the so-called "color" charges. They have nothing to do with ordinary colors and are named so for convenience of description. Each of the six flavors of quarks comes in three color varieties: yellow, blue, or red. (w, s, k respectively). Antiquarks also carry color anticharges. It is important to emphasize that three charges and three anticharges are completely independent of quark flavors. Thus, at present, the total number of quarks and antiquarks (taking into account three colors and six flavors has reached 36. In addition, there are nine more gluons. Gluons, like quarks, are not observed in a free state.
The existence of quarks and gluons leads to the appearance of a new state of matter, which is called quark-gluon plasma.
This is a plasma consisting not of electrons and ions, like ordinary plasma, but of quarks and gluons, weakly interacting with each other or not interacting at all.
One of the main tasks of microphysics, which A. Einstein dreamed of solving, is the creation of a unified field theory that would unite all known fundamental interactions. The creation of such a theory would mean a fundamental breakthrough in all fields of science.
To date, a theory has been created and recognized that combines two fundamental interactions - weak and electromagnetic. It is called unified theory of weak and electromagnetic (electroweak) interaction and claims that there are special particles - carriers of interaction between electrons, protons, neutrons, neutrinos. These particles, called bosons W+, W– and Z°, were theoretically predicted in the 70s. last century and experimentally discovered in 1983.
The theory of strong interaction is called quantum chromodynamics. This theory, which describes the interaction of quarks and gluons, is modeled on quantum electrodynamics, which, in turn, describes electromagnetic interactions due to the exchange of photons. Unlike electrically neutral photons, gluons carry "color" charges. This leads to the fact that when you try to separate them in space, the interaction energy increases. As a result, gluons and quarks do not exist in a free state: they "self-lock" inside hadrons.
The modern theory of elementary particles, consisting of the theories of the electroweak interaction and quantum chromodynamics, is usually called standard model. This complex, but almost complete, phenomenological theory is the main theoretical tool with which the problems of microphysics are solved.
“Great Unification” is the name given to theoretical models based on the concept of the unified nature of the strong, weak and electromagnetic interactions. It is designed to unite all existing particles: fermions, bosons and scalar particles. Within the framework of the Grand Unified theory, many very important phenomena are well explained, in particular, such as the observed gluon asymmetry of the Universe, the small non-zero rest mass of the neutrino, the quantization of electric charge, and the existence of solutions such as Dirac magnetic monopoles. According to the latest data, the average proton lifetime is more than 1.6 10 33 years old. The proof of the instability of the proton would be a discovery of fundamental importance. However, this decay has not yet been recorded. Scientists hope that the further development of the "Great Unification" models will lead to the unification of all interactions, including gravitational (super unification). But this is a matter for the future.
In microphysics, a certain fundamental length is known and plays an important role, called the Planck, or gravitational, length - l g\u003d 1.6 -33 cm. It is believed that a length less than the Planck length does not exist in nature. Together with Planck time t g ~ 1.6 10 -43 s they constitute space-time quanta, which are called upon to form the basis of the future quantum theory of gravity. According to Academician V.L. Ginzburg, the physical meaning of length l g lies in the fact that at smaller scales it is no longer possible to use the classical relativistic theory of gravity and, in particular, general theory relativity (GR), the construction of which was completed by Einstein in 1915.
At present, the smallest "impact parameter" achieved on modern accelerators is lf ~ 10–17 cm. Thus, we can conclude that up to distances lf ~ 10 -17 cm and times lf/c ~ 10–27 s, the existing space-time coordinates are valid. Meaning lf different from the value l g by as many as 16 orders of magnitude, so the question of the fundamental length is still relevant for science.
In the first half of the 20th century, when the objects of study of microphysics were the atom and then the atomic nucleus, in order to understand the behavior of electrons in atoms, it was necessary to make a genuine revolution in science - to create quantum mechanics. Microphysics then occupied a very special place in natural science. Thanks to her successes, we were able to understand the structure of matter. Microphysics is the foundation of modern physical science.
Macroworld
From the microcosm to the macrocosm. The theory of the structure of the atom gave chemistry the key to understanding the essence of chemical reactions and the mechanism of the formation of chemical compounds - a more complex molecular level of organization of material matter compared to the elemental atomic form.
Quantum mechanics made it possible to solve a very important question about the arrangement of electrons in an atom and to establish the dependence of the properties of elements on the structure of electron shells. At present, schemes of the structure of atoms of all chemical elements have been developed. When constructing them, scientists proceeded from general considerations about the stability of various combinations of electrons. And it is natural that the periodic law of D.I. Mendeleev.
When developing schemes for the structure of atoms of elements, the following was taken into account:
1) it was assumed that the number of electrons in an atom is equal to the charge of the atomic nucleus, i.e. the ordinal number of the element in the periodic system;
2) the entire electron shell breaks up into several layers corresponding to certain energy levels (n = 1, 2,3,4,...);
3)at every level P can be no more N electrons, where N \u003d 2p 2;
4) the state of each electron in an atom is determined by a set of four quantum numbers n, l, t and s.
According to the Pauli principle, all electrons in an atom differ from each other by at least one quantum number. There are no two electrons in an atom, in which all quantum numbers are the same, in accordance with the indicated assumptions, simplified schemes of the structure of atoms for the first three periods of the periodic table are constructed.
Despite the conventionality and simplicity of these schemes, they are nevertheless sufficient to explain the most important properties of elements and compounds.
So, for example, at the first energy level ( n=1, l=0, t= 0) there can only be two electrons that differ in their spin quantum numbers (s= ±1/2). Other electrons at n = 1 cannot be. This corresponds to the fact that if there is one electron in the first level, then this is a hydrogen atom; if there are two electrons, then it is a helium atom. Both elements fill the first row of the periodic table.
The second row of the periodic table is occupied by elements whose electrons are located on the second energy level ( P= 2). There can be eight electrons in the second energy level. (N=2· 2 2).
Indeed, at P= 2, the following states of electrons can take place: if l = 0 and t= 0, then there can be two electrons with opposite spins; if l = 1, then t can take three values (t= –1; 0; +1), and each value t also corresponds to two electrons with different spins. Thus, there will be eight electrons in total.
The second row of elements in the periodic table, in which one electron is sequentially added at the second energy level, is lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, neon.
With the main quantum number P= 3 l can take three values ( l=0; one; 2), and each l matches multiple values t. at l= 0 t= 0; at l~ 1 t= –1; 0; +1; at l=2 t=–2; -one; 0; I 1; +2 (Fig. 2.4).
Since there can be nine values in total t, and every state t corresponds to two electrons different values s=±1/2, but only at the third energy level (n = 3) can be 18 electrons (n = 2· Z 2).
The third row in the periodic table corresponds to the sequential filling of the outer energy level with electrons in elements from sodium to argon (sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, argon).
Energy levels and possible states of electrons in an atom: the possible orbits in which an electron in an atom moves around the nucleus can be depicted as circles (A), each of which exactly fits an integer number of light wavelengths equal to the main quantum number P. A two-dimensional analogue of an atom can be described by two quantum numbers, while a real atom is characterized by three quantum numbers.
The next rows of the periodic system correspond to more complex rules for filling the outer levels of atoms with electrons, since with an increase in the total number of electrons, and atoms, collective interactions begin to appear between different groups of electrons located on different energy levels. This leads to the need to take into account a number of more subtle effects.
Elucidation of the structure of the electron shells of atoms had an impact on the very structure of the periodic system, somewhat changing the division of elements into periods that existed until then. In the old tables, each period began with an inert gas, with hydrogen remaining outside the periods. But now it has become clear that the new period must begin with the element in whose atom a new electron layer first appears in the form of one valence electron (hydrogen and alkali metals), and end with the element in whose atom this layer has eight electrons, forming very strong electronic structure characteristic of inert gases.
The theory of the structure of atoms also resolved the question of the position in the periodic system of rare earth elements, which, due to their great similarity with each other, could not be distributed into different groups. The atoms of these elements differ from each other in the structure of one of the inner electron layers, while the number of electrons in the outer layer, on which the chemical properties of the element mainly depend, is the same for them. For this reason, all rare earth elements (lanthanides) are now placed outside the general table.
However, the main significance of the theory of the structure of atoms was to reveal the physical meaning of the periodic law, which, but at the time of Mendeleev, was still unclear. It is enough to look at the table of the arrangement of electrons in the atoms of chemical elements to make sure that with an increase in charges atomic nuclei the same combinations of electrons are constantly repeated in the outer layer of the atom. Thus, a periodic change in the properties of chemical elements occurs due to a periodic return to the same electronic configurations.
Let us try to establish more precisely the dependence of the chemical properties of atoms on the structure of the electron shells.
Consider first the change in properties in periods. Within each period (except the first), the metallic properties, most pronounced in the first member of the period, gradually weaken and give way to metalloid properties in the transition to subsequent members: at the beginning of the period there is a typical metal, at the end - a typical metalloid (non-metal) and behind it - inert gas.
The regular change in the properties of elements in periods can be explained as follows. The most characteristic property of metals from a chemical point of view is the ability of their atoms to easily give up external electrons and turn into positively charged ions, while metalloids, on the contrary, are characterized by the ability to attach electrons to form negative ions.
To detach an electron from an atom with the transformation of the latter into a positive ion, you need to expend some energy, which is called ionization potential.
The ionization potential has the lowest value for elements starting a period, i.e. for hydrogen and alkali metals, and the largest - for elements ending the period, i.e. for inert gases. Its value can serve as a measure of the greater or lesser "metallicity" of an element: the lower the ionization potential, the easier it is to detach an electron from an atom, the stronger the metallic properties of the element should be expressed.
The value of the ionization potential depends on three reasons: on the value of the charge of the nucleus, the radius of the atom, and a special kind of interaction between electrons in the electric field of the nucleus, caused by their wave properties. Obviously, the greater the charge of the nucleus and the smaller the radius of the atom, the stronger the electron is attracted to the nucleus, the greater the ionization potential.
For elements of the same period, when moving from alkali metal to an inert gas, the charge of the nucleus gradually increases, and the radius of the atom decreases. The consequence of this is a gradual increase in the ionization potential and a weakening metallic properties. Inert gases, although the radii of their atoms are larger than the radii of halogen atoms in the same period, have ionization potentials greater than those of halogens. In this case, the effect of the third of the above factors, the interaction between electrons, is strongly affected, as a result of which the outer electron shell of an inert gas atom has a special energy stability, and the removal of an electron from it requires a much greater expenditure of energy.
The attachment of an electron to a metalloid atom, which transforms its electron shell into a stable shell of an inert gas atom, is accompanied by the release of energy. The value of this energy, when calculated per 1 gram-atom of an element, serves as a measure of the so-called electron affinity. The greater the affinity for an electron, the easier it is for an atom to attach an electron. The affinity of metal atoms for an electron is zero, - metal atoms are not able to attach electrons. For atoms of metalloids, the affinity for an electron is the greater, the closer the metalloid is to an inert gas in the periodic system. Therefore, within a period, the metalloid properties increase as the end of the period approaches.
AT Everyday life we don't have to deal with atoms. The world around us is built from objects formed from a gigantic number of atoms in the form of solids, liquids and gases. Therefore, our next step should be to study how atoms interact with each other, forming molecules, and then macroscopic matter. Even human individuality (and in general the behavior of all living organisms) is the result of differences in the structures of giant molecules that carry genetic information.
Molecules are made up of identical or different atoms linked together by interatomic chemical bonds. The stability of molecules indicates that chemical bonds are due to the interaction forces that bind atoms into a molecule.
The forces of interatomic interaction arise between the outer electrons of atoms. The ionization potentials of these electrons are much lower than those of electrons located at internal energy levels.
Finding specific formulas of chemical compounds is greatly simplified if you use the concept of the valence of elements, i.e. the property of its atoms to attach to itself or replace a certain number of atoms of another element.
The concept of valence extends not only to individual atoms, but also on whole groups of atoms that make up chemical compounds and participate as a whole in chemical reactions. Such groups of atoms are called radicals.
Physical foundations of chemical bonds in substance molecules. However, the nature of the forces that determine the bond between atoms in molecules remained unknown for a long time. Only with the development of the theory of the structure of the atom, theories appeared that explained the reason for the different valency of elements and the mechanism for the formation of chemical compounds on the basis of electronic representations. All these theories are based on the existence of a connection between chemical and electrical phenomena.
Let us dwell, first of all, on the relation of substances to electric current.
Some substances are conductors of electric current, both in solid and in liquid state: such, for example, are all metals. Other substances in the solid state do not conduct current, but are electrically conductive when molten. These include the vast majority of salts, as well as many oxides and hydrates of oxides. Finally, the third group consists of substances that do not conduct current in either the solid or liquid state. This includes almost all metalloids.
Experience has established that the electrical conductivity of metals is due to the movement of electrons, and the electrical conductivity of molten salts and similar compounds is due to the movement of ions with opposite charges. For example, when a current passes through molten salt, positively charged sodium ions Na + move towards the cathode, and negatively charged chloride ions Cl - move towards the anode. Obviously, in salts, ions already exist in solid matter, melting will only create conditions for their free movement. Therefore, these compounds are called ionic compounds. Substances that practically do not conduct current do not contain ions: they are built from electrically neutral molecules or atoms. Thus, the different ratio of substances to electric current is a consequence of the different electrical state of the particles that form these substances.
The above types of substances correspond to two different types chemical bond:
a) ionic bond, otherwise called electrovalent (between oppositely charged ions in ionic compounds);
b) atomic, or covalent, bond (between electrically neutral atoms in the molecules of all other substances).
Ionic bond This type of bond exists between oppositely charged ions and is formed as a result of a simple electrostatic attraction of ions to each other.
Positive ions are formed by splitting off electrons from atoms, negative - by attaching electrons to atoms.
So, for example, a positive Na + ion is formed when one electron is split off from a sodium atom. Since there is only one electron in the outer layer of the sodium atom, it is natural to assume that it is this electron, as the most distant from the nucleus, that is split off from the sodium atom when it is converted into an ion. Similarly, magnesium Mg 2+ and aluminum A1 3+ ions are obtained as a result of the elimination of two and three outer electrons from magnesium and aluminum atoms, respectively.
On the contrary, negative ions of sulfur and chlorine are formed by attaching electrons to these atoms. Since the inner electron layers in the chlorine and sulfur atoms are filled, the additional electrons in the S 2 and Cl - ions, obviously, should have taken places in the outer layer.
Comparing the composition and structure of the electron shells of Na +, Mg 2+, A1 3+ ions, we see that they are the same for all these ions - the same as for atoms of the inert gas neon (Ne).
At the same time, S 2 and Cl ions - , formed as a result of the addition of electrons to sulfur and chlorine atoms, have the same electron shells as argon (Ar) atoms.
Thus, in the considered cases during the transformation of atoms into ions electron shells ions are likened to the shells of atoms of inert gases, located closest to them in the periodic system.
The modern theory of chemical bonding explains
