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The mechanical, electromagnetic and quantum-relativistic scientific picture of the world is a law. Development of the electromagnetic picture of the world Contribution to the picture of the world electromagnetic theory

In the process of long reflections on the essence of electrical and magnetic phenomena, M. Faraday came to the idea of the need to replace corpuscular ideas about matter with continual, continuous ones. He concluded that the electromagnetic field is completely continuous, the charges in it are point centers of force. Thus, the question of constructing a mechanical model of the ether, the discrepancy between mechanical ideas about the ether and real experimental data on the properties of light, electricity and magnetism, has disappeared. The main difficulty in explaining light using the concept of ether was the following: if the ether is a continuous medium, then it should not impede the movement of bodies in it and, therefore, should be similar to a very light gas. In experiments with light, two fundamental facts were established: light and electromagnetic oscillations are not longitudinal, but transverse, and the propagation velocity of these oscillations is very high. In mechanics, it was shown that transverse vibrations are possible only in solids, and their speed depends on the density of the body. For such a high speed as the speed of light, the density of the ether must have been many times greater than the density of steel. But then, how do bodies move?

Maxwell was one of the first to appreciate Faraday's ideas. At the same time, he emphasized that Faraday put forward new philosophical views on matter, space, time and forces, which largely changed the previous mechanical picture of the world.

Views on matter changed dramatically: the totality of indivisible atoms ceased to be the ultimate limit of the divisibility of matter, as such a single absolutely continuous infinite field with power point centers - electric charges and wave motions in it was taken.

Movement was understood not only as a simple mechanical movement, the propagation of oscillations in a field became primary in relation to this form of movement, which was described not by the laws of mechanics, but by the laws of electrodynamics.

Newton's concept of absolute space and time was not suitable for field representations. Since the field is absolutely continuous matter, there is simply no empty space. Likewise, time is inextricably linked with the processes taking place in the field. Space and time ceased to be independent entities independent of matter. The understanding of space and time as absolute gave way to a relational (relative) concept of space and time.

The new picture of the world required a new solution to the problem of interaction. The Newtonian concept of long-range action was replaced by the Faraday principle of short-range action; any interactions are transmitted by the field from point to point continuously and at a finite speed. *

Although the laws of electrodynamics, like the laws of classical mechanics, unambiguously predetermined events, and they still tried to exclude chance from the physical picture of the world, the creation of the kinetic theory of gases introduced the concept of probability into the theory, and then into the electromagnetic picture of the world. True, so far physicists have not given up hope of finding clear, unambiguous laws similar to Newton's laws behind the probabilistic characteristics.

The idea of the place and role of man in the Universe did not change in the electromagnetic picture of the world. His appearance was considered only a whim of nature. Ideas about the qualitative specifics of life and mind with great difficulty made their way into the scientific worldview.

The new electromagnetic picture of the world explained a wide range of phenomena that were incomprehensible from the point of view of the previous mechanical picture of the world. It revealed more deeply the material unity of the world, since electricity and magnetism were explained on the basis of the same laws.

However, insurmountable difficulties soon began to arise along this path. So, according to the electromagnetic picture of the world, the charge began to be considered a point center, and the facts testified to the finite extent of the particle-charge. Therefore, already in Lorentz's electronic theory, a particle-charge, contrary to the new picture of the world, was considered in the form of a solid charged ball with mass. The results of Michelson's experiments in 1881 - 1887, where he tried to detect the motion of a body by inertia with the help of instruments located on this body, turned out to be incomprehensible. According to Maxwell's theory, such a movement could be detected, but experience did not confirm this. But then physicists tried to forget about these minor troubles and inconsistencies, moreover, the conclusions of Maxwell's theory were absolutized, so that even such a prominent physicist as Kirchhoff believed that there was nothing unknown and undiscovered in physics.

But by the end of the XIX century. more and more inexplicable discrepancies between theory and experience accumulated. Some were due to the incompleteness of the electromagnetic picture of the world, others were not at all consistent with the continuum ideas about matter: difficulties in explaining the photoelectric effect, the line spectrum of atoms, the theory of thermal radiation.

Consistent application of Maxwell's theory to other moving media led to conclusions about the non-absolute nature of space and time. However, the belief in their absoluteness was so great that scientists were surprised at their conclusions, called them strange and rejected them. This is exactly what Lorentz and Poincaré did, whose work ends the pre-Einstein period in the development of physics.

Accepting the laws of electrodynamics as the basic laws of physical reality, A. Einstein introduced the idea of the relativity of space and time into the electromagnetic picture of the world and thereby eliminated the contradiction between the understanding of matter as a certain type of field and Newtonian ideas about space and time. The introduction of relativistic concepts of space and time into the electromagnetic picture of the world opened up new possibilities for its development.

This is how the general theory of relativity appeared, which became the last major theory created within the framework of the electromagnetic picture of the world. In this theory, created in 1916, Einstein for the first time gave a deep explanation of the nature of gravity, for which he introduced the Concept of the relativity of space and time and the curvature of a single four-dimensional space-time continuum, depending on the distribution of masses.

But even the creation of this theory could no longer save the electromagnetic picture of the world. From the end of the 19th century more and more irreconcilable contradictions between electromagnetic theory and facts were discovered. In 1897, the phenomenon of radioactivity was discovered and it was found that it is associated with the transformation of some chemical elements into others and is accompanied by the emission of alpha and beta rays. On this basis, empirical models of the atom appeared, contradicting the electromagnetic picture of the world. And in 1900, M. Planck, in the process of numerous attempts to construct a theory of radiation, was forced to make an assumption about the discontinuity of radiation processes.

FEDERAL AGENCY FOR EDUCATION

ROSTOV STATE ECONOMIC UNIVERSITY "RINH"

FACULTY OF COMMERCE AND MARKETING

CHAIR OF PHILOSOPHY AND CULTUROLOGY

on the topic: "Electromagnetic picture of the world"

Completed:

student gr. 211 E.V. Popov

Checked:

Rostov-on-Don

Introduction

1. Basic experimental laws of electromagnetism

2. The theory of electromagnetic field D. Maxwell

3. Lorentz electronic theory

Conclusion

Bibliography

Introduction

One of the most important characteristics of a person, which distinguishes him from an animal, is that in his actions he relies on reason, on a system of knowledge and their assessment. The behavior of people, the degree of effectiveness of the tasks they solve, of course, depends on how adequate and deep their understanding of reality is, to what extent they can correctly assess the situation in which they have to act and apply their knowledge.

For a long time in human life, not only those knowledge that had direct practical significance, but also those that related to general ideas about nature, society and man himself, acquired great importance. It is the latter, as it were, that hold together the spiritual world of people into a single whole. On their basis, traditions arose, formed and developed in all spheres of human activity. An important role is played by how a person represents the structure of the world. Human self-consciousness tends to imagine the surrounding world, i.e. see with the mind's eye what is called the Universe, and find your place among the surrounding things, determine your position in the cosmic and natural hierarchy. Since ancient times, people have been concerned about questions about the structure of the universe, about the possibility of its knowledge, its practical development, about the fate of peoples and all mankind, about happiness and justice in human life. Without the desire to comprehend the world in its integrity, the desire to understand nature and social phenomena, mankind would not have created science, art, or literature.

Modern science is aimed at building a single, integral picture of the world, depicting it as an interconnected "web of being". In the public consciousness, different pictures of the world historically develop and gradually change, which an ordinary person perceives as a given, as an objectivity that exists independently of our personal opinions. The picture of the world means, as it were, a visible portrait of the universe, a figurative conceptual copy of the Universe, looking at which, one can understand and see the connections of reality and one's place in it. It implies an understanding of how the world works, what laws it is governed by, what underlies it and how it develops. Therefore, the concept of "picture of the world" occupies a special place in the structure of natural science.

Pictures of the world give a person a certain place in the Universe and help him navigate in being. Each of the pictures of the world gives its own version of what the world really is and what place a person occupies in it. In part, the pictures of the world contradict each other, and in part they are complementary and capable of forming a whole. With the development of science, one picture of the world is replaced by another. This is called the scientific revolution, meaning by it a radical break in the previous ideas about the world. Each picture of the world retains from its predecessors the best, the most important, corresponding to the objective structure of the Universe. The new picture is more difficult than the old one. From a philosophical point of view, the world is reality, taken as a whole, grasped in some of its qualitative unity. However, the world as a whole is not given to us directly, insofar as we take a concrete position; we are partial and limited to a small segment of reality.

1. Basic experimental laws of electromagnetism

Consider the electromagnetic picture of the world since its inception. Physics has made a significant contribution to this picture.

Electromagnetic phenomena have been known to mankind since antiquity. The very concept of "electrical phenomena" dates back to the times of Ancient Greece, when the ancient Greeks tried to explain the phenomenon of repulsion of two pieces of amber rubbed with a cloth from each other, as well as attraction of small objects by them. Subsequently, it was found that there are, as it were, two types of electricity: positive and negative.

As for magnetism, the properties of some bodies to attract other bodies were known in ancient times, they were called magnets. The property of a free magnet was established in the North-South direction already in the 2nd century BC. BC. used in ancient China during travel. The first experimental study of a magnet in Europe was carried out in France in the 13th century. As a result, it was found that the magnet has two poles. In 1600, Gilbert put forward the hypothesis that the Earth is a large magnet: this is the reason for the possibility of determining the direction using a compass.

The 18th century, which was marked by the formation of a mechanical picture of the world, actually marked the beginning of systematic research into electromagnetic phenomena. So it was found that the charges of the same name repel each other, the simplest device appeared - the electroscope. In the middle of the XVIII century. the electrical nature of lightning was established (the studies of B. Franklin, M. Lomonosov, G. Richman, and Franklin's merits should be especially noted: he is the inventor of the lightning rod; it is believed that it was Franklin who proposed the designations "+" and "-" for electric charges).

In 1759, the English naturalist R. Simmer concluded that in the normal state, any body contains an equal number of opposite charges that mutually neutralize each other. When electrified, they are redistributed.

At the end of the 19th and the beginning of the 20th century, it was experimentally established that the electric charge consists of an integer number of elementary charges e = 1.6 * 10 -19 C. This is the smallest charge that exists in nature. In 1897, J. Thomson also discovered the smallest stable particle, which is the carrier of an elementary negative charge. This is an electron with a mass m e = 9.1 * 10 -31 kg. Thus, the electric charge is discrete, i.e. consisting of separate elementary portions q = ± n*e, where n is an integer. As a result of numerous studies of electrical phenomena undertaken in the 18th - 19th centuries, a number of important laws were obtained by thinkers, such as:

1) the law of conservation of electric charge: in an electrically closed system, the sum of charges is a constant value, i.e. electric charges can arise and disappear, but at the same time, an equal number of elementary charges of opposite signs necessarily appear and disappear;

2) the magnitude of the charge does not depend on its speed;

3) the law of interaction of point charges, or Coulomb's law:

where ε is the relative permittivity of the medium (in vacuum ε = 1). According to this law, the Coulomb forces are significant at distances up to 10-15 m (lower limit). At smaller distances, nuclear forces begin to act (the so-called strong interaction). As for the upper limit, it tends to infinity.

The study of the interaction of charges, carried out in the XIX century. it is also remarkable that together with him the concept of "electromagnetic field" was introduced into science. In the process of formation of this concept, the mechanical model of "ether" was replaced by an electromagnetic model: electric, magnetic and electromagnetic fields were treated initially as different "states" of the ether. Subsequently, the need for ether disappeared. The understanding came that the electromagnetic field itself is a certain type of matter and for its propagation no special medium "ether" is required.

The proof of these statements are the works of the outstanding English physicist M. Faraday. The field of fixed charges is called electrostatic. An electric charge, being in space, distorts its properties, i.e. creates a field. The power characteristic of an electrostatic field is its intensity. The electrostatic field is potential. Its energy characteristic is the potential φ.

The nature of magnetism remained unclear until the end of the 19th century, and electrical and magnetic phenomena were considered independently of each other, until in 1820 the Danish physicist H. Oersted discovered the magnetic field near a current-carrying conductor. So the connection between electricity and magnetism was established. The strength characteristic of the magnetic field is the intensity. Unlike non-closed electric field lines (Fig. 1), the magnetic field lines are closed (Fig. 2), i.e. it is vortex.

During September 1820, the French physicist, chemist and mathematician A.M. Ampère develops a new section of the science of electricity - electrodynamics.

Ohm's laws, Joule-Lenz became one of the most important discoveries in the field of electricity. The law discovered by G. Ohm in 1826, according to which in the circuit section I \u003d U / R and for a closed circuit I \u003d EMF / (R + r), as well as the Joule-Lenz law Q \u003d I * U * t for the amount of heat , released during the passage of current through a fixed conductor during time t, significantly expanded the concepts of electricity and magnetism.

The studies of the English physicist M. Faraday (1791-1867) gave a certain completeness to the study of electromagnetism. Knowing about the discovery of Oersted and sharing the idea of the relationship between the phenomena of electricity and magnetism, Faraday in 1821 set the task of "transforming magnetism into electricity." After 10 years of experimental work, he discovered the law of electromagnetic induction. The essence of the law is that a changing magnetic field leads to the emergence of an EMF of induction EMF i = k * dФ m / dt, where dФ m / dt is the rate of change of the magnetic flux through the surface stretched on the circuit. From 1831 to 1855 Faraday's main work "Experimental Investigations in Electricity" is published in the form of series.

Working on the study of electromagnetic induction, Faraday comes to the conclusion about the existence of an electromagnetic field. One of the first to appreciate the work of Faraday and his discoveries was D. Maxwell, who developed the ideas of Faraday, having developed in 1865 the theory of the electromagnetic field, which significantly expanded the views of physicists on matter and led to the creation of an electromagnetic picture of the world.

2. The theory of electromagnetic field D. Maxwell

The concept of lines of force proposed by Faraday was not taken seriously by other scientists for a long time. The fact is that Faraday, not knowing the mathematical apparatus well enough, did not give a convincing justification for his conclusions in the language of formulas. (“It was a mind that never got bogged down in formulas,” A. Einstein said about him).

The brilliant mathematician and physicist James Maxwell defends Faraday's method, his ideas of short-range action and field, arguing that Faraday's ideas can be expressed in the form of ordinary mathematical formulas, and these formulas are comparable to those of professional mathematicians.

D. Maxwell develops the field theory in his works "On the physical lines of force" (1861-1865) and "Dynamic field theory" (1864-1865). In the last work, a system of famous equations was given, which, according to G. Hertz, constitute the essence of Maxwell's theory.

This essence boiled down to the fact that a changing magnetic field creates not only in the surrounding bodies, but also in vacuum a vortex electric field, which, in turn, causes the appearance of a magnetic field. Thus, a new reality was introduced into physics - the electromagnetic field. This marked the beginning of a new stage in physics, the stage at which the electromagnetic field became a reality, a material carrier of interaction.

The world began to appear as an electrodynamic system built from electrically charged particles interacting through an electromagnetic field.

The system of equations for electric and magnetic fields developed by Maxwell consists of 4 equations, which are equivalent to four statements:

Analyzing his equations, Maxwell came to the conclusion that electromagnetic waves must exist, and the speed of their propagation must be equal to the speed of light. This led to the conclusion that light is a kind of electromagnetic waves. Based on his theory, Maxwell predicted the existence of pressure exerted by an electromagnetic wave, and, consequently, by light, which was brilliantly proved experimentally in 1906 by P.N. Lebedev.

The pinnacle of Maxwell's scientific work was the Treatise on Electricity and Magnetism.

Having developed the electromagnetic picture of the world, Maxwell completed the picture of the world of classical physics (“the beginning of the end of classical physics”). Maxwell's theory is the forerunner of Lorentz's electronic theory and A. Einstein's special theory of relativity.

3. Lorentz electronic theory

The Dutch physicist G. Lorenz (1853-1928) believed that Maxwell's theory needed to be supplemented, since it did not take into account the structure of matter. Lorentz expressed in this connection his ideas about electrons, i.e. extremely small electrically charged particles, which are present in huge quantities in all bodies.

In 1895, Lorentz gives a systematic exposition of the electronic theory, based, on the one hand, on Maxwell's theory, and on the other hand, on the concept of "atomicity" (discreteness) of electricity. In 1897, the electron was discovered, and Lorentz's theory received its material basis.

Together with the German physicist P. Drude, Lorentz developed the electronic theory of metals, which is based on the following provisions.

1. There are free electrons in the metal - conduction electrons that form an electron gas.

2. The base of the metal forms a crystal lattice, in the nodes of which there are ions.

3. In the presence of an electric field, the random motion of electrons is superimposed by their ordered motion under the action of field forces.

4. During their movement, the electrons collide with the ions of the lattice. This explains the electrical resistance.

The electronic theory made it possible to quantitatively describe many phenomena, but in a number of cases, for example, in explaining the dependence of the resistance of metals on temperature, etc., it was practically powerless. This was due to the fact that, in the general case, the laws of Newtonian mechanics and the laws of ideal gases cannot be applied to electrons, which was clarified in the 30s of the XX century.

Conclusion

As discussed earlier, the electromagnetic picture of the world continued to form throughout the 20th century. She used not only the doctrine of magnetism and the achievements of atomism, but also some ideas of modern physics (the theory of relativity and quantum mechanics). After various fields became the object of study of physics along with matter, the picture of the world became more complex, but still it was a picture of classical physics.

Its main features are as follows. According to this picture, matter exists in two forms - matter and field, between which there is an impassable line: matter does not turn into a field and vice versa. There are two types of fields - electromagnetic and gravitational, respectively - two types of fundamental interactions. Fields, unlike matter, are continuously distributed in space. Electromagnetic interaction explains not only electrical and magnetic phenomena, but also others - optical, chemical, thermal. More and more it comes down to electromagnetism. Outside the sphere of domination of electromagnetism, only gravitation remains.

As elementary "bricks" of which all matter consists, three particles are considered - an electron, a proton and a photon. Photons are quanta of the electromagnetic field. The corpuscular-wave dualism "reconciles" the wave nature of the field with the corpuscular one, i.e. when considering the electromagnetic field, along with wave, and corpuscular (photon) representations are used. The elementary "building blocks" of matter are electrons and protons. A substance consists of molecules, molecules of atoms, an atom has a massive nucleus and an electron shell. The nucleus is made up of protons. The forces acting in matter are reduced to electromagnetic forces. These forces are responsible for intermolecular bonds and bonds between atoms in a molecule; they keep the electrons of the atomic shell close to the nucleus; they also provide the strength of the atomic nucleus (which later turned out to be incorrect). The electron and proton are stable particles, so atoms and their nuclei are also stable. The picture, at first glance, looked flawless. But such "little things" as it was considered then, for example, radioactivity, etc., did not fit into this framework. It soon became clear that these "little things" are fundamental. It was they who led to the "collapse" of the electromagnetic picture of the world.

The electromagnetic picture of the world represented a huge step forward in the knowledge of the world. Many of its details have been preserved in the modern natural science picture: the concept of a physical field, the electromagnetic nature of the forces responsible for various phenomena in matter (but not in the atoms themselves), the nuclear model of the atom, the dualism (duality) of the corpuscular and wave properties of matter, etc. But also this picture of the world is also dominated by unambiguous causal relationships, everything is rigidly predetermined in the same way. Probabilistic physical regularities are not recognized as fundamental and therefore are not included in it either. These probabilities were attributed to molecules, and the molecules themselves still followed unambiguous Newtonian laws. Ideas about the place and role of man in the universe have not changed. Thus, the electromagnetic picture of the world is also characterized by metaphysical thinking, where everything is clearly demarcated, there are no internal contradictions.

Bibliography

1. Diaghilev F.M. Concepts of modern natural science. - M.: Ed. IEMPE, 1998.

2. Nedelsky N.F., Oleinikov B.I., Tulinov V.F. Concepts of modern natural science. - M: Ed. Thought, 1996.

3. Grushevitskaya T.G., Sadokhin A.P. Concepts of modern natural science.- M.: Ed. UNITY, 2005.

4. Karpenkov S.Kh. Basic concepts of natural science. – M.: Ed. UNITY, 2004.

Already in the XIX century. physicists supplemented the mechanistic picture of the world electromagnetic. Electric and magnetic phenomena have been known for a long time, but they were studied separately from each other. Their further study showed that there is a deep relationship between them, which forced scientists to create a unified electromagnetic theory. Indeed, the Danish scientist X. Oersted(1777-1851), having placed a magnetic needle over a conductor through which an electric current flows, he found that it deviates from its original position. This led the scientist to the idea that an electric current creates a magnetic field. Later, the English physicist M. Faraday (1791-1867), rotating a closed circuit in a magnetic field, discovered that an electric current arises in it. Based on the experiments of Oersted, Faraday and other scientists, the English physicist J. Maxwell (1831-1879) created his electromagnetic theory, i.e. theory of the existence of a single electromagnetic field. In this way it was shown that in the world there is not only substance in the form of bodies, but also physical fields.

After various fields became objects of study for physicists along with matter, the picture of the world became more complex. Nevertheless, at first, scientists tried to explain electromagnetic processes, including light phenomena, using mechanical models based on the concepts and principles of the mechanistic picture of the world. This can be seen by referring to a brief history of the appearance of the first hypotheses about the nature of electricity and magnetism.

4.1. Hypotheses about weightless electric and magnetic fluids

Rudiments of old ideas about electricity are still preserved in the scientific language. We constantly hear physicists say that electric current flows through a conductor from a high potential to

lower, as if electricity were like a liquid. At the very beginning of research, electrical and magnetic phenomena were actually considered as weightless, positively and negatively charged liquids, since with the help of such hypotheses it was possible to explain the experiments known by that time. Such experiments are usually carried out when studying a physics course in high school.

If you rub an ebonite rod with a piece of woolen cloth and then bring it to the metal head of an electroscope, then its leaves diverge. From this it is concluded that as a result of friction, the ebonite rod became negatively charged and transferred this charge to the electroscope. The leaves of the electroscope, charged with the same electricity, repel each other and therefore diverge. Similarly, if you rub a glass rod with cat fur, it becomes positively charged. When you touch the electroscope, the leaves charged with positive electricity of the same name will also disperse.

The hypothesis of the existence of weightless electric fluids is based on the following assumptions:

1. Electricity is a certain substance, like a substance, namely a liquid.

2. In every uncharged body there is the same amount of positive and negative electricity, and therefore they mutually neutralize each other. At the same time, what kind of electricity to call positive or negative is a purely conditional question.

3. As a result of certain actions, such as friction, one kind of electricity can be separated from another.

4. There are two kinds of bodies, in some of them electrical fluids can move freely, and therefore they are called conductors of electricity. In others, they cannot move, and therefore they are called insulators. Conductors include metals, earth, the human body. For insulators - porcelain, glass, rubber, etc.

All these assumptions, although they explain the simplest experiments with electrical phenomena, are connected with attempts to extend the mechanistic concept of weightless liquids to phenomena that are fundamentally different from mechanical phenomena. Since the flow of a liquid occurs at its different levels, it was necessary to introduce the concepts of potential difference for electricity. However, the question arises: does the weight of a charged body differ from that of an electrically neutral body?

Experience shows that their weight is the same. To reconcile this fact with the assumption of the existence of electric fluids, it was necessary to declare them weightless substances, and thereby move away from the mechanistic concept.

Weightless substances used to be invented in large numbers to explain a number of new phenomena of a non-mechanical nature. So, for example, heat was also considered as an imponderable substance, like a liquid that flows from a hot body to a cold one, if they are brought into contact. As a result, their temperature will become the same. However, it is completely different with electricity, because when interacting with oppositely charged bodies, they become electrically neutral.

With the further development of research on the phenomena of electricity, attempts to explain them with the help of mechanistic ideas ran into more serious difficulties. Even at the end of the XVIII century. the Italian scientist A. Volta (1745-1827) built a device that is now known as a voltaic column, consisting of several elements. Each such element is a battery in which copper and zinc plates are lowered into a vessel where water and a little sulfuric acid are poured. If you connect these plates with a wire, then an electric current will appear in the circuit. Between the copper and zinc plates, according to the hypothesis of electric fluid, a potential difference should arise, which, in the case of two charged bodies connected by a wire, quickly disappears, but continues to be preserved in the battery. This led Volta to suggest that the plates "supply an unlimited charge or produce a continuous action or impulse of the electrical fluid". Please note that Volta still considers electricity as a liquid. He does not reveal and does not analyze the cause of the potential difference on the plates as a result of the occurrence of chemical processes in the solution, and thus does not consider it as a process of converting chemical energy into electrical energy.

At the end of the XIX century. the place of hypothetical electric and magnetic fluids was taken by a new concept of a single electromagnetic field. If in mechanics changes and movement of material particles are made with the help of external forces applied to particles or a body formed from them, then in electrodynamics changes are made under the influence of field forces.

4.2. Electromagnetic field and its features

Initially, in the studies of M. Faraday, the concept of an electromagnetic field played an auxiliary role and served as a visual illustration for demonstrating the forces of the field. However, later it became the same fundamental concept as the concept of things.

stva. It is based, as we have noted, on two major discoveries that linked electrical and magnetic phenomena into one whole. As we already know, Oersted established that a magnetic field arises around a conductor through which an electric current flows. In subsequent studies of physicists, it was found that the new force arising under the influence of current depends on the speed of movement of the electric charge and is directed perpendicular to the plane of this movement.

Later, Faraday discovered the completely opposite phenomenon of electromagnetic induction, which indicated that a changing magnetic field creates an electric field and, therefore, causes an electric current.

Thus, the electric and magnetic fields are not isolated objects, but form an interconnected, unified electromagnetic field. Where there is an electric field, there must be a magnetic field, and a magnetic field creates an electric field.

However, this important conclusion applies only to changing fields. Indeed, an electric charge moving through a conductor, or current, is a changing, alternating field. It is this that creates a magnetic field around the conductor. If there is no movement of electric charges, then there will be no magnetic field. For example, a static electric field exists around a motionless, electrically charged ball, but since the ball remains motionless, no magnetic field is formed around it. As soon as the ball is set in motion, a magnetic field will appear around it. Similarly, a stationary magnet, around which there is a static magnetic field, does not create an electric field in a closed conductor located nearby, and therefore no electric current. Consequently, static electric and magnetic fields that do not change in space and over time do not create a single electromagnetic field. Only when we are dealing with moving electric and magnetic charges, i.e. with alternating fields, an interaction occurs between them and a single electromagnetic field appears.

The establishment of a deep inner connection and unity between previously isolated electrical and magnetic phenomena, which were previously considered as a special kind of weightless liquids, was an outstanding achievement in physics. The concept of the electromagnetic field, which arose on this basis, put an end to numerous attempts at the mechanical interpretation of electromagnetic phenomena. Even the interpretation of lines of force as mechanical tension

field, which was used even by Faraday, lost its meaning after the great English physicist J. Maxwell built the mathematical theory of the electromagnetic field.

This theory is a generalization of all empirical relationships established by Oersted, Faraday and other scientists in the study of electrical and magnetic phenomena. But this generalization is by no means reduced to summing up their results, but presupposes the idealization of the processes under study. Maxwell in his imagination imagined the ideal case of Faraday's experiment, when a closed curve intersected by magnetic lines contracts to a certain point in space. In this limiting case, the magnitude and shape of the closed curve do not play any significant role, and therefore it becomes possible to consider the laws that relate changes in the magnetic and electric fields at any point in space and at any moment in time. The same imaginary case can be done with Oersted's experiment and consider the laws that relate changes in the electric and magnetic fields at any moment in time and at any point in space.

There is a certain connection between the laws of the electromagnetic field, expressed in Maxwell's equations, and the laws of Newton's mechanics. When studying mechanical laws, we found out that, knowing the coordinates of a body, its speed and the equation of motion, it is possible to accurately determine its position and speed at any point in space at any moment in the future or past. For this, as is known, ordinary differential equations are used.

Maxwell's equations make it possible, knowing the state of the field at any point in time, to determine how it will change over time. But there is also a significant difference between the laws of mechanics and electromagnetism. If, for a given state of motion of a material point, the laws of mechanics make it possible to determine its trajectory and position at any arbitrary moment in time in any place, then Maxwell's laws make it possible to determine the state of the electromagnetic field in close proximity to its previous state. Relatively speaking, in mechanics, when determining the state of motion of a system, they rely on the idea of long-range action. According to the principle of long-range action, the author of which was the French scientist and philosopher R. Descartes, a force effect can be transmitted instantly to any distance through empty space. In the theory of the electromagnetic field, such a possibility is denied, and therefore it is based on the principle of short-range action. This allows you to follow step by step the change in the electromagnetic field over time.

When studying the motion of material particles or systems formed from them, the history of changes in their states can be studied along their trajectories. In the electromagnetic theory, one has to turn to the changes that occur with the field in space. Therefore, for the mathematical description of the electromagnetic field, one turns to differential equations with partial derivatives. If in mechanics change and movement are always considered taking into account the interaction of the bodies themselves, which are the source of movement, i.e. an external force that causes this movement, then in the theory of the electromagnetic field they abstract from such sources and consider only the change in the field in space over time as a whole. Moreover, the source that creates the field may eventually cease to operate, although the field generated by it continues to exist.

Finally, the consequence of the existence of electromagnetic waves and the speed of their propagation follows from Maxwell's equations. Indeed, an oscillating electric charge creates a changing electric field, which is accompanied by a changing magnetic field. If there is a closed conductor nearby, then an electric current arises in it, which creates a magnetic field, etc. As a result of oscillations of electric charges, a certain energy is radiated into the surrounding space in the form electromagnetic waves, that propagate at a certain speed. Since the direction of energy propagation is perpendicular to the direction of the field lines of force, electromagnetic waves are transverse.

Experimental studies have established that the propagation velocity of electromagnetic waves is 300,000 km/s. Since light propagates at the same speed, it was logical to assume that there is a certain commonality between electromagnetic and light phenomena.

4.3. Relationship between electromagnetism and optics

The establishment of equality between the speed of light and the speed of propagation of electromagnetic waves was a new major step in revealing the unity between outwardly different phenomena of nature.

On the question of the nature of light, before the discovery of Maxwell's electromagnetic theory, there were two competing hypotheses: corpuscular and wave.

Supporters corpuscular hypotheses, beginning with Newton, considered light as a stream of light corpuscles, or discrete particles. Such a hypothesis was in good agreement with the principles of the mechanistic worldview, whose supporters quite convincingly explained the rectilinear propagation of light, its refraction, or refraction during the transition from one medium to another, and even dispersion, or the decomposition of white light into its constituent colors, etc. However, the corpuscular hypothesis failed to explain more complex phenomena such as interference and diffraction of light.

Wave interference is the superposition of coherent light waves. When at the same time the crests of the waves coincide, then their amplitudes add up and the light is amplified. If the crest of one wave coincides with the trough of another, then the amplitude of one wave is subtracted from the other, and instead of light, a weakening of light or even darkness appears in this place. This experience at the very beginning of the XIX century. produced by the English physician T. Jung. If light beams are passed through two closely spaced pinholes, then behind a dark screen one can observe the alternation of light and dark rings. Light rings appear in those places where the crests of the waves coincide, dark ones - in the places where the crests and troughs of the waves coincide. Thus, under interference understand the amplification or attenuation of light when superimposed light waves. It is clear that the phenomenon of interference cannot be explained with the help of corpuscular concepts of light.

The same must be said about another phenomenon called diffraction, arising from the deviation of light from a rectilinear direction. This phenomenon is observed when light passes through narrow gaps or around obstacles. On a screen placed behind them, one can observe alternating light and dark circles, which should not be, according to the corpuscular theory.

Defenders wave hypotheses consider light as a process of wave propagation, similar to the movement of waves on the surface of a liquid. With the help of this hypothesis, they were able to explain not only all the phenomena that the corpuscular hypothesis explained, but also those that were difficult or not at all to be explained using the previous hypothesis (interference and diffraction). That is why in the 19th century the wave hypothesis of light supplanted the corpuscular hypothesis from optics.

Light waves, like waves on the surface of a liquid, propagate perpendicular to the oscillatory process and, therefore, belong to transverse waves. In contrast to them, sound waves are called longitudinal waves, since the direction of their propagation coincides with the direction of air movement. By-

Since light waves, like waves on the surface of a liquid, arise as a result of vertical oscillations of their particles, the question inevitably arises: what medium serves as a source of light oscillations? As an answer to it, a hypothesis was put forward about the existence of a light ether that fills the entire world space and has the properties of elasticity. As a result, the transmission of light was associated with the vibrations of the ether. However, the existence of such an ether was not discovered by any experiments, and therefore, in the future, it was completely abandoned.

After the discovery of electromagnetic waves, the propagation speed of which was equal to the speed of light, scientists came to the conclusion that light is a special kind of electromagnetic waves. It differs from ordinary electromagnetic waves in its extremely small wavelength, which is 4.7 10 -5 cm for visible and 10 -6 cm for invisible, ultraviolet light. Long electromagnetic waves, such as radio waves, can travel thousands of kilometers.

Thus, the first important result of the electromagnetic concept was the rejection of the hypothesis of the existence of the light ether as a special medium for the propagation of light. This role began to play the very space in which the propagation of electromagnetic waves.

The second result is the unification of light phenomena with electromagnetic processes, thanks to which optics has become part of the theory of electromagnetism. However, at the beginning of the XX century. phenomenon was discovered photoelectric effect, which is the emission of electrons by a substance when exposed to light. The electromagnetic theory of light was unable to explain the independence of the energy of the photoelectric effect from the intensity of illumination. Even at the end of the XIX century. Russian physicist A.G. Stoletov found that the energy of the photoelectric effect increases with the frequency of light, but does not depend on its intensity. This result clearly contradicted the predictions of electromagnetic theory.

To explain the photoelectric effect, A. Einstein had to abandon the wave concepts of light and turn to its quantum nature, i.e. in a modified form to revive again the corpuscular point of view on light. For the first time, they started talking about quanta in 1900, when the famous German physicist M. Planck proved that energy is emitted and absorbed not continuously, but in separate portions, or quanta. In 1905, Einstein showed that light propagates in the form of a stream of light quanta, which were called photons. The energy of photons depends on their frequency, i.e. E= hv , where h is Planck's constant, v - frequency.

The quantum view of the nature of light could not completely refute the idea of its wave nature, as evidenced by the phenomena of interference and diffraction. How could quantum and wave representations be combined in a single picture? We will learn about this later, when we get acquainted with quantum mechanics and the theory of elementary particles.

4.4. Field and substance

The introduction of the concept of an electromagnetic field has expanded the scientific understanding of the forms of matter studied in physics. Classical, Newtonian physics dealt with only one single form of physical matter - a substance that was built from material particles and was a system of such particles, which were considered either material points (mechanics) or atoms (the doctrine of heat).

If the main characteristic of a substance is mass, since it is precisely this that appears in the basic law of mechanics F = that then in electrodynamics the concept of field energy is fundamental. In other words, when studying motion in mechanics, first of all, they pay attention to the movement of bodies with mass, and when studying the electromagnetic field, to the propagation of electromagnetic waves in space over time. Another difference between a substance and a field is also the nature of the transfer of influences. In mechanics, such an action is transmitted by force, and it can be carried out in principle over any distance, while in electrodynamics, the energy action of the field is transmitted from one point to another.

Finally, one should also note the important fact that, after the source of electromagnetic waves ceases to operate, the resulting electromagnetic waves continue to propagate in space. It turns out that electromagnetic waves can exist autonomously, without direct connection with an energy source.

Historically, the approach to the study of nature from the point of view of matter and the mass associated with it found a clear expression in the mechanistic picture of the world, which tried to explain other, non-mechanical phenomena using the concepts and principles of mechanics. It is based on the idea of the discrete nature of matter, which in mechanics was considered as a system of material parts.

tyts, and in other sciences - a set of atoms or molecules. In this way, discreteness can be regarded as the final divisibility of matter into separate, ever-decreasing parts. Even the ancient Greeks understood that such divisibility cannot continue indefinitely, because then matter itself will disappear. Therefore, they put forward the assumption that the last indivisible particles of matter are atoms.

From a discrete point of view, the structure of matter can be represented as such a structure, which implies the possibility of its final division into ever-decreasing separate parts, starting from molecules and atoms and ending with elementary particles and quarks.

From point of view continuity matter is represented as a certain integrity and unity. A clear image of such continuity is any continuous medium that fills a certain space. The properties of such a medium, such as a liquid, change from one point to another continuously, without interruption of gradualness and jumps. Using the electromagnetic field as an example, we have seen that the force effect of such a field is transmitted from the nearby previous point to the next one, i.e. continuously.

In the classical theory, there was an explicit opposition between discreteness and continuity, when any interaction between them was excluded in the study of matter and field. In modern physics, as we will see later, it is the relationship and interaction of discreteness and continuity, corpuscular and wave properties of matter in the study of the properties and laws of motion of its smallest particles that serves as the basis for an adequate description of the studied phenomena and processes. Such microparticles of matter are characterized by corpuscular-wave dualism, i.e. they simultaneously possess both the properties of corpuscles (substance) and waves (field).

Such a representation is completely alien to classical physics, in which the discrete and corpuscular approach was used in the study of some phenomena, and the continuous and field approach was used in the study of others. Moreover, we now know that the mechanistic interpretation of the phenomena of electricity and magnetism was ultimately based on their discrete and corpuscular interpretation, when they were considered as special substances, i.e. when identified with a kind of substance.

A more universal approach to a unified explanation of all physical phenomena from the point of view of a unified field theory was put forward as a grandiose program by the creator of the theory of relativity, A. Einstein, but remained unrealized. Its main

ideas will become clear after we get acquainted with the theory of relativity.

The dialectical interaction of discreteness and continuity finds its vivid embodiment in modern quantum field theories. Indeed, the interaction in the quantum theory of the electromagnetic field occurs as a result of the mutual exchange of photons, quanta of this field. The same can be said about the gravitational field, where such interaction is carried out with the help of gravitons, hypothetical particles of such a field. Particles, or quanta, of the field at each point in space create a field of forces that has its effect on other particles.

The field itself has been interpreted in different ways in the history of physics. In the first concepts of electromagnetism, the field was considered purely mechanically, namely, as a tension of lines of force between charges, and in optics as an elastic oscillation of a special, all penetrating medium - the world ether. After the rejection of such an assumption, first in the theory of the electromagnetic field, and then in the theory of relativity, the role of a kind of ether in modern physics is apparently claimed by physical vacuum. In quantum field theory, it is considered as the lowest energy state of quantized fields, in which there are no real particles. However, the possibility of virtual processes in vacuum leads to certain effects when it interacts with real particles. In quantum field theory, the concept of physical vacuum is considered the main one, since its properties determine the properties of all other states of the system.

Thus, with the development of physics, ideas about matter and field have changed radically. Their former opposition in classical physics has given way to an understanding of their relationship and interaction in modern physics. On the one hand, matter is considered as a certain discrete system of interacting elementary particles. On the other hand, the field as a continuous integrity consists of field quanta that exchange energy with each other and thus ensure the existence and movement of the system itself.

Basic concepts and questions

short range long range

Vacuum (physical) Resolution

Substance Diffraction

Wave Interference

Quantum of energy Photoelectric effect

Optics Electromagnetic induction

Radio waves Electromagnetic field

Light Electromagnetic vibrations

1. How were the phenomena of electricity and magnetism originally explained?

2. What discoveries became the basis for the creation of the theory of the electromagnetic field?

3. In what cases do electric charges create a magnetic field?

4. What is a static electric field?

5. In what case can a static field turn into a dynamic field and form a magnetic field?

6. When does a magnet create an electric field?

7. What is the relationship between electricity and magnetism?

8. What discoveries did Maxwell rely on when creating his theory of the electromagnetic field?

9. What new consequences were obtained from Maxwell's theory?

10. Why did optical phenomena come to be regarded as electromagnetic?

11. What is the nature of electromagnetic waves?

12. How do light waves differ from other electromagnetic waves?

13. How is the transfer of energy in an electromagnetic field?

14. What is the difference between a field and a substance?

Literature

Main:

Philosophy of Science. Modern philosophical problems of scientific fields

knowledge. M., 2005. Einstein A., Infeld L. Evolution of physics // Einstein A. Sobr. scientific

Proceedings: In 4 vols. T. 4. S. 401-452. 100 years of quantum theory. History. Physics. Philosophy. M., 2002.

Additional:

Feynman Lectures on Physics. Issue. 3. Radiation. Waves. Quanta. M.,

1966. Ch. 28. Feynman lectures on physics. Issue. 5. Electricity and magnetism. M.,

1966. Ch. 1. Philosophy: encyclopedic dictionary / Ed. A.A. Ivin. M., 2004.

FEDERAL AGENCY FOR EDUCATION

ROSTOV STATE ECONOMIC UNIVERSITY "RINH"

FACULTY OF COMMERCE AND MARKETING

CHAIR OF PHILOSOPHY AND CULTUROLOGY

on the topic: "Electromagnetic picture of the world"

Completed:

student gr. 211 E.V. Popov

Checked:

Rostov-on-Don

Introduction

1. Basic experimental laws of electromagnetism

2. The theory of electromagnetic field D. Maxwell

3. Lorentz electronic theory

Conclusion

Bibliography

Introduction

1. Basic experimental laws of electromagnetism

Consider the electromagnetic picture of the world since its inception. Physics has made a significant contribution to this picture.

2) the magnitude of the charge does not depend on its speed;

3) the law of interaction of point charges, or Coulomb's law:

. The electrostatic field is potential. Its energy characteristic is the potential φ.

. Unlike non-closed electric field lines (Fig. 1), the magnetic field lines are closed (Fig. 2), i.e. it is vortex.

During September 1820, the French physicist, chemist and mathematician A.M. Ampère develops a new section of the science of electricity - electrodynamics.

The electromagnetic picture of the world began to take shape in the second half of the 19th century. based on research in the field of electromagnetism. The main role here was played by the studies of M. Faraday and D. Maxwell, who introduced the concept of a physical field. In the process of formation of this concept, the mechanical model of the ether was replaced by the electromagnetic model: electric, magnetic and electromagnetic fields were treated initially as different "states" of the ether. Subsequently, the need for ether disappeared. The understanding came that the electromagnetic field itself is a certain type of matter and for its propagation some special medium-ether is not required.

The electromagnetic picture of the world continued to form during three decades of the 20th century. She used not only the doctrine of magnetism and the achievements of atomism, but also some ideas of modern physics (the theory of relativity and quantum mechanics). After various fields became the object of study of physics along with matter, the picture of the world became more complex, but still it was a picture of classical physics.

Its main features are as follows. According to this picture, matter exists in two forms - matter and field, between which there is an impassable line: matter does not turn into a field and vice versa. There are two types of fields - electromagnetic and gravitational, respectively - two types of fundamental interactions. Fields, unlike matter, are continuously distributed in space. Electromagnetic interaction explains not only electrical and magnetic phenomena, but also others - optical, chemical, thermal. Now everyone is trying to reduce to electromagnetism. Outside the sphere of domination of electromagnetism, only gravitation remains.

As elementary "bricks" of which all matter consists, three particles are considered - an electron, a proton and a photon. Photons are quanta of the electromagnetic field. The corpuscular-wave dualism "reconciles" the wave nature of the field with the corpuscular one, i.e. when considering the electromagnetic field, along with wave, and corpuscular (photon) representations are used. The elementary "building blocks" of matter are electrons and protons. A substance consists of molecules, molecules of atoms, an atom has a massive nucleus and an electron shell. The nucleus is made up of protons. The forces acting in matter were reduced to electromagnetic forces. These forces are responsible for intermolecular bonds and bonds between atoms in a molecule; they keep the electrons of the atomic shell close to the nucleus; they also provide the strength of the atomic nucleus (which turned out to be incorrect). The electron and proton are stable particles, so atoms and their nuclei are also stable. The picture, at first glance, looked flawless. But such "little things" as it was considered then, for example, radioactivity, etc., did not fit into this framework. It soon became clear that these "little things" are fundamental. It was they who led to the "collapse" of the electromagnetic picture of the world.

The electromagnetic picture of the world represented a huge step forward in the knowledge of the world. Many of its details have been preserved in the modern natural science picture: the concept of a physical field, the electromagnetic nature of the forces responsible for various phenomena in matter (but not in the atoms themselves), the nuclear model of the atom, the dualism (duality) of corpuscular and wave properties of matter, etc. But even in this picture of the world unambiguous cause-and-effect relationships also dominate, everything is rigidly predetermined in the same way. Probabilistic physical regularities are not recognized as fundamental and therefore are not included in it either. These probabilities were attributed to collectives of molecules, and the molecules themselves still followed unambiguous Newtonian laws. Ideas about the place and role of man in the universe have not changed. Thus, the electromagnetic picture of the world is also characterized by metaphysical thinking, where everything is clearly demarcated, there are no internal contradictions.