MAXWELL James Clerk (Maxwell James Clerk) (13. VI.1831 - 5. XI.1879) - English physicist, member of the Edinburgh (1855) and London (1861) Royal Society. R. in Edinburgh. He studied at Edinburgh (1847-50) and Cambridge (1850-54) high school. After the latter, he taught for a short period at Trinity College, in 1856 - 60 - professor at the University of Aberdeen, in 1860 - 65 - at King's College London, and from 1871 - the first professor of experimental physics at Cambridge. Under his leadership, the famous Cavendish Laboratory was created in Cambridge, which he headed until the end of his life.
The works are devoted to electrodynamics, molecular physics, general statistics, optics, mechanics, and elasticity theory. Maxwell made his most significant contributions to molecular physics and electrodynamics.
In the kinetic theory of gases, of which he was one of the founders, he established in 1859 a statistical law describing the velocity distribution of gas molecules (Maxwell's distribution). In 1866, he gave a new derivation of the velocity distribution function of molecules, based on the consideration of direct and reverse collisions, and developed the theory of transport in general view, applying it to the processes of diffusion, thermal conductivity and internal friction, introduced the concept of relaxation time.
In 1867, the first showed the statistical nature of the second law of thermodynamics (“Maxwell’s demon”), and in 1878 he introduced the term “statistical mechanics.” 
Maxwell's greatest scientific achievement is the theory of the electromagnetic field he created in 1860 - 65, which he formulated in the form of a system of several equations (Maxwell's equations), expressing all the basic laws of electromagnetic phenomena (the first differential equations fields were recorded by Maxwell in 1855 - 56). In his theory of the electromagnetic field, Maxwell used (1861) a new concept - displacement current, gave (1864) a definition of the electromagnetic field and predicted (1865) a new important effect: the existence in free space of electromagnetic radiation (electromagnetic waves) and its propagation in space at the speed of light . The latter gave him reason to consider (1865) light one of the types of electromagnetic radiation (the idea of the electromagnetic nature of light) and to reveal the connection between optical and electromagnetic phenomena. Theoretically calculated the pressure of light (1873). Set the ratio ε
= n 2 (1860).
Predicted the effects of Stewart - Tolman and Einstein - de Haas (1878), the skin effect.
He also formulated a theorem in the theory of elasticity (Maxwell’s theorem), established relationships between the main thermophysical parameters (Maxwell’s thermodynamic relationships), developed the theory of color vision, and studied the stability of Saturn’s rings, showing that the rings are not solid or liquid, but are a swarm of meteorites.
Designed a number of devices.
He was a famous popularizer of physical knowledge.
Published for the first time (1879) manuscripts of G. Cavendish .
Essays:
- Selected Works on the Theory of the Electromagnetic Field. - State Publishing House of Technical and Theoretical Literature. M., 1952 (Series "Classics of Natural Sciences").
- Speeches and Articles. State publishing house of technical and theoretical literature. M.-L., 1940 (Series "Classics of Natural Sciences").
- Matter and Motion. - Izhevsk, Research Center "Regular and Chaotic Dynamics", 2001.
- Treatise on electricity and magnetism. - M., Sciences, 1989 (Series "Classics of Science"). Volume 1. Volume 2.
- Excerpts from works:
Literature:
- V. Kartsev. Maxwell. Life wonderful people. Young guard; Moscow; 1974
Movies:
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International University of Nature, Society and Human "Dubna"
Department of Sustainable Innovative Development
RESEARCH WORK
on the topic of:
"Contributions to Science by James Clerk Maxwell"
Completed by: Pleshkova A.V., gr. 5103
Checked by: Bolshakov B. E.
Dubna, 2007
The formulas we arrive at must be such that a representative of any nation, substituting numerical values of quantities measured in its national units instead of symbols, would obtain the correct result.
J.C. Maxwell
Biography 5
Discoveries of J. C. Maxwell 8
Edinburgh. 1831-1850 8
Childhood and school years 8
First opening 9
Edinburgh University 9
Optical-mechanical research 9
1850-1856 Cambridge 10
Electricity lessons 10
Aberdeen 1856-1860 12
Treatise on the Rings of Saturn 12
London - Glenlair 1860-1871 13
First color photograph 13
Probability theory 14
Mechanical Maxwell Model 14
Electromagnetic waves and electromagnetic theory of light 15
Cambridge 1871-1879 16
Cavendish Laboratory 16
World recognition 17
Dimension 18
Law of Conservation of Power 22
List of used literature 23
Introduction
Today, the views of J. C. Maxwell, one of the greatest physicists of the past, whose name is associated with fundamental scientific achievements included in the gold fund modern science. Maxwell is interesting to us as an outstanding methodologist and historian of science, who deeply understood the complexity and inconsistency of the process of scientific research. Analyzing the relationship between theory and reality, Maxwell exclaimed in shock: “But who will lead me into the still more hidden nebulous region where Thought is combined with Fact, where we see the mental work of the mathematician and the physical action of molecules in their true proportions? Does not the road to them pass through the very lair of metaphysicians, strewn with the remains of previous explorers and instilling horror in every man of science?.. In our daily work we come to questions of the same kind as metaphysicians, but without relying on the innate insight of our minds, we approach them prepared by long-term adaptation of our way of thinking to the facts external nature" (James Clerk Maxwell. Articles and speeches. M., “Science”, 1968. P.5).Biography
Born into the family of a Scottish nobleman from a noble family of Clerks. He studied first at Edinburgh (1847-1850), then at Cambridge (1850-1854) universities. In 1855 he became a member of the council of Trinity College, in 1856-1860. was a professor at Marischal College, University of Aberdeen, and from 1860 headed the department of physics and astronomy at King's College, University of London. In 1865, due to a serious illness, Maxwell resigned from the chair and settled on his family estate of Glenlare near Edinburgh. He continued to study science and wrote several essays on physics and mathematics. In 1871 he took the chair of experimental physics at the University of Cambridge. He organized a research laboratory, which opened on June 16, 1874 and was named Cavendish in honor of G. Cavendish.
Maxwell completed his first scientific work while still at school, inventing a simple way to draw oval shapes. This work was reported at a meeting of the Royal Society and even published in its Proceedings. While a member of the Council of Trinity College, he was involved in experiments on color theory, acting as a continuator of Jung's theory and Helmholtz's theory of three primary colors. In experiments on color mixing, Maxwell used a special top, the disk of which was divided into sectors, colored in different colors(Maxwell disk). When the top rotated quickly, the colors merged: if the disk was painted in the same way as the colors of the spectrum, it appeared white; if one half of it was painted red and the other half yellow, it appeared orange; mixing blue and yellow created the impression of green. In 1860, Maxwell was awarded the Rumford Medal for his work on color perception and optics.
In 1857, Cambridge University announced a competition for better job about the stability of Saturn's rings. These formations were discovered by Galileo at the beginning of the 17th century. and presented an amazing mystery of nature: the planet seemed surrounded by three continuous concentric rings, consisting of a substance of an unknown nature. Laplace proved that they cannot be solid. After spending mathematical analysis, Maxwell became convinced that they could not be liquid, and came to the conclusion that such a structure could only be stable if it consisted of a swarm of unrelated meteorites. The stability of the rings is ensured by their attraction to Saturn and the mutual movement of the planet and meteorites. For this work, Maxwell received the J. Adams Prize.
One of Maxwell's first works was his kinetic theory of gases. In 1859, the scientist gave a report at a meeting of the British Association in which he presented the distribution of molecules by speed (Maxwellian distribution). Maxwell developed the ideas of his predecessor in the development of the kinetic theory of gases by R. Clausius, who introduced the concept of “mean free path”. Maxwell proceeded from the idea of a gas as an ensemble of many ideally elastic balls moving chaotically in a closed space. Balls (molecules) can be divided into groups according to speed, while in a stationary state the number of molecules in each group remains constant, although they can leave and enter groups. From this consideration it followed that “particles are distributed by speed according to the same law as observational errors are distributed in the theory of the method least squares, i.e. in accordance with Gaussian statistics." As part of his theory, Maxwell explained Avogadro's law, diffusion, thermal conductivity, internal friction (transfer theory). In 1867 he showed the statistical nature of the second law of thermodynamics (“Maxwell’s demon”).
In 1831, the year Maxwell was born, M. Faraday carried out classical experiments that led him to the discovery of electromagnetic induction. Maxwell began to study electricity and magnetism about 20 years later, when there were two views on the nature of electric and magnetic effects. Scientists such as A. M. Ampere and F. Neumann adhered to the concept of long-range action, viewing electromagnetic forces as analogous to the gravitational attraction between two masses. Faraday was an adherent of the idea of lines of force that connect positive and negative electrical charges or north and south poles magnet Lines of force fill the entire surrounding space (field, in Faraday's terminology) and determine electrical and magnetic interactions. Following Faraday, Maxwell developed a hydrodynamic model of lines of force and expressed the then known relations of electrodynamics in a mathematical language corresponding to Faraday's mechanical models. The main results of this research are reflected in the work “Faraday’s Lines of Force” (Faraday’s Lines of Force, 1857). In 1860-1865 Maxwell created the theory of the electromagnetic field, which he formulated in the form of a system of equations (Maxwell's equations) describing the basic laws of electromagnetic phenomena: the 1st equation expressed Faraday's electromagnetic induction; 2nd - magnetoelectric induction, discovered by Maxwell and based on ideas about displacement currents; 3rd - the law of conservation of electricity; 4th - vortex nature of the magnetic field.
Continuing to develop these ideas, Maxwell came to the conclusion that any changes in the electric and magnetic fields must cause changes in the lines of force that penetrate the surrounding space, that is, there must be pulses (or waves) propagating in the medium. The speed of propagation of these waves (electromagnetic disturbance) depends on the dielectric and magnetic permeability of the medium and is equal to the ratio of the electromagnetic unit to the electrostatic one. According to Maxwell and other researchers, this ratio is 3 x 1010 cm/s, which is close to the speed of light measured seven years earlier French physicist A. Fizeau. In October 1861, Maxwell informed Faraday of his discovery: light is an electromagnetic disturbance propagating in a non-conducting medium, that is, a type of electromagnetic wave. This final stage of research is outlined in Maxwell’s work “The Dynamic Theory of the Electromagnetic Field” (Treatise on Electricity and Magnetism, 1864), and the result of his work on electrodynamics was summed up in the famous “Treatise on Electricity and Magnetism”. (1873)
Last years During his lifetime, Maxwell was involved in the preparation for printing and publication of Cavendish's manuscript heritage. Two large volumes were published in October 1879.
Discoveries of J. C. Maxwell
Edinburgh. 1831-1850
Childhood and school years
On June 13, 1831, in Edinburgh, at number 14 India Street, Frances Kay, the daughter of an Edinburgh judge, after her marriage to Mrs. Clerk Maxwell, gave birth to a son, James. On this day, nothing significant happened all over the world; the main event of 1831 had not yet happened. But for eleven years the brilliant Faraday has been trying to comprehend the secrets of electromagnetism, and only now, in the summer of 1831, he picked up the trail of the elusive electromagnetic induction, and James will be only four months old when Faraday sums up his experiment “to obtain electricity from magnetism.” And thus will open a new era - the era of electricity. The era for which little James, a descendant of the glorious families of the Scottish Clerks and Maxwells, will live and create.James's father, John Clerk Maxwell, a lawyer by profession, hated the law and had a dislike, as he himself said, for "dirty lawyering." Whenever the opportunity arose, John stopped his endless shuffling around the marble vestibules of the Edinburgh court and devoted himself to scientific experiments, which he did casually, amateurishly. He was an amateur, he was aware of this and took it hard. John was in love with science, with scientists, with practical people, with his learned grandfather George. It was the attempts to construct bellows, which were carried out jointly with his brother Frances Kay, that brought him together with his future wife; the wedding took place on October 4, 1826. The bellows never worked, but a son, James, was born.
When James was eight, his mother died and he was left to live with his father. His childhood is filled with nature, communication with his father, books, stories about his relatives, “scientific toys,” and his first “discoveries.” James's family was concerned that he was not receiving a systematic education: random reading of everything in the house, astronomy lessons on the porch of the house and in the living room, where James and his father built a “celestial globe.” After an unsuccessful attempt to study with a private teacher, from whom James often ran away to more exciting activities, it was decided to send him to study in Edinburgh.
Despite being educated at home, James met the high standards of the Edinburgh Academy and was enrolled there in November 1841. His performance in the classroom was far from stellar. He could easily perform tasks better, but the spirit of competition in unpleasant activities was deeply alien to him. After the first day of school, he did not get along with his classmates, and therefore, more than anything else, James loved to be alone and look at the objects around him. One of the most bright events What undoubtedly brightened up the dull school days was a visit with my father to the Royal Society of Edinburgh, where the first “electromagnetic machines” were exhibited.
The Royal Society of Edinburgh changed James' life: it was there that he received the first concepts of the pyramid, cube, and other regular polyhedra. The perfection of symmetry and the natural transformations of geometric bodies changed James’s concept of learning - he saw in learning a grain of beauty and perfection. When the time for exams came, the students of the academy were amazed - the “fools,” as they called Maxwell, became one of the first.
First discovery
If earlier his father occasionally took James to his favorite entertainment - meetings of the Royal Society of Edinburgh, now visits to this society, as well as the Edinburgh Society of Arts, together with James became regular and obligatory for him. At the meetings of the Society of Arts the most famous and crowd-pulling speaker was Mr. D.R. Hey, decorative artist. It was his lectures that prompted James to make his first major discovery - a simple tool for drawing ovals. James found an original and at the same time very simple method, and most importantly, a completely new one. He described the principle of his method in a short “paper”, which was read at the Royal Society of Edinburgh - an honor that many have sought, but which was awarded to a fourteen-year-old schoolboy.Edinburgh University
Optical-mechanical research
In 1847, studies at the Edinburgh Academy ended, James was one of the first, the grievances and worries of the first years were forgotten.After graduating from the academy, James enters the University of Edinburgh. At the same time, he began to become seriously interested in optical research. Brewster's statements led James to the idea that studying the path of rays could be used to determine the elasticity of a medium in different directions, to detect stresses in transparent materials. Thus, the study of mechanical stresses can be reduced to an optical study. Two beams, separated in a tense transparent material, will interact, giving rise to characteristic colorful pictures. James showed that color paintings are completely natural in nature and can be used for calculations, for checking previously derived formulas, and for deriving new ones. It turned out that some formulas are incorrect, or inaccurate, or need amendments.
Fig. 1 is a picture of stresses in a stele triangle obtained by James using polarized light.
Moreover, James was able to discover patterns in cases where previously nothing could be done due to mathematical difficulties. A transparent and loaded triangle of untempered glass (Fig. 1) gave James the opportunity to study stresses in this calculable case.
Nineteen-year-old James Clerk Maxwell stood on the podium of the Royal Society of Edinburgh for the first time. His report could not go unnoticed: it contained too much new and original.
1850-1856 Cambridge
Electricity classes
Now no one questioned James' talent. He had clearly outgrown the University of Edinburgh and therefore entered Cambridge in the fall of 1850. In January 1854, James graduated with honors from the university with a bachelor's degree. He decides to stay in Cambridge to prepare for a professorship. Now that he does not need to prepare for exams, he gets the long-awaited opportunity to spend all his time on experiments and continues his research in the field of optics. He is especially interested in the question of primary colors. Maxwell's first article was called "The Theory of Colors in Connection with Color Blindness" and was not even an article, but a letter. Maxwell sent it to Dr. Wilson, who found the letter so interesting that he took care of its publication: he placed it in its entirety in his book on color blindness. And yet James is unconsciously drawn to deeper secrets, things much more unobvious than the mixing of colors. It was electricity, due to its intriguing incomprehensibility, that inevitably, sooner or later, had to attract the energy of his young mind. James took it quite easily fundamental principles intense electricity. Having studied Ampere's theory of long-range action, he, despite its apparent irrefutability, allowed himself to doubt it. The theory of long-range action seemed undoubtedly correct, because was confirmed by the formal similarity of laws and mathematical expressions for seemingly different phenomena - gravitational and electrical interaction. But this theory, more mathematical than physical, did not convince James; he was increasingly inclined to the Faraday perception of action through magnetic lines of force filling space, to the theory of short-range action.Trying to create a theory, Maxwell decided to use the method of physical analogies for research. First of all, it was necessary to find the right analogy. Maxwell always admired the analogy that existed at that time, only just noticed, between the issues of attraction of electrically charged bodies and the issues of steady-state heat transfer. James gradually built this, as well as Faraday's ideas of short-range action and Ampere's magnetic action of closed conductors, into a new theory, unexpected and bold.
At Cambridge, James is assigned to teach the most difficult chapters of hydrostatics and optics courses to the most capable students. In addition, he was distracted from electrical theories by work on a book on optics. Maxwell soon comes to the conclusion that optics no longer interests him as before, but only distracts him from the study of electromagnetic phenomena.
Continuing to look for an analogy, James compares the lines of force with the flow of some incompressible fluid. The theory of tubes from hydrodynamics made it possible to replace the lines of force with force tubes, which easily explained Faraday's experiment. The concepts of resistance, the phenomena of electrostatics, magnetostatics and electric current easily and simply fit into the framework of Maxwell's theory. But this theory still doesn’t fit into this theory. discovered by Faraday phenomenon of electromagnetic induction.
James had to abandon his theory for some time due to the deterioration of his father's condition, which required care. When James returned to Cambridge after the death of his father, he was unable to obtain a higher master's degree due to his religion. Therefore, in October 1856, James Maxwell took up the chair in Aberdeen.
Aberdeen 1856-1860
Treatise on the Rings of Saturn
It was in Aberdeen that the first work on electricity was written - the article "On Faraday's Lines of Force", which led to an exchange of views on electromagnetic phenomena with Faraday himself.When James began his studies in Aberdeen, a new problem had already matured in his head, which no one could solve yet, a new phenomenon that had to be explained. These were Saturn's rings. To determine their physical nature, to determine them from millions of kilometers away, without any instruments, using only paper and a pen, was a task as if for him. The hypothesis of a solid rigid ring disappeared immediately. The liquid ring would disintegrate under the influence of the giant waves that arose in it - and as a result, according to James Clerk Maxwell, there would most likely be a host of small satellites hovering around Saturn - “brick fragments”, in his perception. For his treatise on the rings of Saturn, James was awarded the Adams Prize in 1857, and he himself is recognized as one of the most authoritative English theoretical physicists.
Fig.2 Saturn. Photograph taken with the 36-inch refractor at Lick Observatory.
Fig.3 Mechanical models illustrating the movement of Saturn's rings. Drawings from Maxwell's essay “On the Stability of the Rotation of the Rings of Saturn”
London – Glenlair 1860-1871
First color photograph
In 1860, a new stage in Maxwell's life began. He was appointed to the position of professor of the department natural philosophy at King's College London. King's College was ahead of many universities in the world in terms of the equipment of its physics laboratories. Here Maxwell is not just in 1864-1865. taught a course in applied physics, here he tried to organize the educational process in a new way. Students learned through experimentation. In London, James Clerk Maxwell first tasted the fruits of his recognition as a major scientist. For his research on color mixing and optics, the Royal Society awarded Maxwell the Rumford Medal. On May 17, 1861, Maxwell was offered the high honor of giving a lecture before the Royal Institution. The topic of the lecture is “On the theory of three primary colors.” At this lecture, as proof of this theory, color photography was demonstrated to the world for the first time!Probability theory
At the end of the Aberdeen period and at the beginning of the London period, Maxwell developed, along with optics and electricity, a new hobby - the theory of gases. Working on this theory, Maxwell introduces into physics such concepts as “probably”, “this event can occur with a greater degree of probability.”A revolution had taken place in physics, and many who listened to Maxwell's reports at the annual meetings of the British Association did not even notice it. On the other hand, Maxwell approached the limits of the mechanical understanding of matter. And he stepped over them. Maxwell's conclusion about the dominance of the laws of probability theory in the world of molecules affected the most fundamental foundations of his worldview. The statement that in the world of molecules “chance reigns” was, in its boldness, one of greatest feats in science.
Maxwell's mechanical model
Work at King's College required much more time than at Aberdeen - the lecture course lasted nine months a year. However, at this time, thirty-year-old James Clerk Maxwell is sketching out a plan for his future book on electricity. This is the embryo of the future Treatise. He devotes his first chapters to his predecessors: Oersted, Ampere, Faraday. Trying to explain Faraday's theory of lines of force, the induction of electric currents and Oersted's theory of the vortex-like nature of magnetic phenomena, Maxwell creates his own mechanical model (Fig. 5).The model consisted of rows of molecular vortices rotating in one direction, between which was placed a layer of tiny spherical particles capable of rotation. Despite its cumbersomeness, the model explained many electromagnetic phenomena, including electromagnetic induction. The sensational nature of the model was that it explained the theory of the action of a magnetic field at right angles to the direction of current, formulated by Maxwell (“the gimlet rule”).
Fig. 4 Maxwell eliminates the interaction of neighboring vortices A and B rotating in one direction by introducing “idler gears” between them
Fig.5 Maxwell's mechanical model for explaining electromagnetic phenomena.
Electromagnetic waves and electromagnetic theory of light
Continuing his experiments with electromagnets, Maxwell came closer to the theory that any changes in electric and magnetic force send waves that propagate through space.After a series of articles “On Physical Lines,” Maxwell already had, in fact, all the material for constructing a new theory of electromagnetism. Now for the theory of the electromagnetic field. The gears and vortices completely disappeared. For Maxwell, the field equations were no less real and tangible than the results of laboratory experiments. Now both Faraday's electromagnetic induction and Maxwell's displacement current were derived not using mechanical models, but using mathematical operations.
According to Faraday, a change in the magnetic field leads to the appearance of an electric field. A surge in the magnetic field causes a surge in the electric field.
A burst of an electric wave gives rise to a burst of a magnetic wave. Thus, for the first time, from the pen of a thirty-three-year-old prophet, electromagnetic waves appeared in 1864, but not yet in the form in which we understand them now. Maxwell spoke only about magnetic waves in an 1864 paper. An electromagnetic wave in the full sense of the word, including both electric and magnetic disturbances, appeared later in Maxwell's paper in 1868.
In another article by Maxwell, “The Dynamic Theory of the Electromagnetic Field,” the previously outlined electromagnetic theory of light acquired clear outlines and evidence. Based on his own research and the experience of other scientists (most notably Faraday), Maxwell concludes that the optical properties of a medium are related to its electromagnetic properties, and light is nothing more than electromagnetic waves.
In 1865, Maxwell decides to leave King's College. He settles in his family estate of Glenmeir, where he studies the main works of his life - “The Theory of Heat” and “Treatise on Electricity and Magnetism.” I devote all my time to them. These were the years of hermitage, years of complete detachment from vanity, serving only science, the most fruitful, bright, creative years. However, Maxwell is again drawn to work at the university, and he accepts the offer made to him by the University of Cambridge.
Cambridge 1871-1879
Cavendish Laboratory
In 1870, the Duke of Devonshire announced to the University Senate his desire to build and equip a physics laboratory. And it was to be headed by a world-famous scientist. This scientist was James Clerk Maxwell. In 1871, he began work on equipping the famous Cavendish Laboratory. During these years, his “Treatise on Electricity and Magnetism” was finally published. More than a thousand pages, where Maxwell gives a description of scientific experiments, an overview of all the theories of electricity and magnetism created so far, as well as the “Basic Equations of the Electromagnetic Field.” In general, in England they did not accept the main ideas of the Treatise; even their friends did not understand it. Maxwell's ideas were picked up by young people. Maxwell's theory made a great impression on Russian scientists. Everyone knows the role of Umov, Stoletov, Lebedev in the development and strengthening of Maxwell's theory.June 16, 1874 is the day of the grand opening of the Cavendish Laboratory. The following years were marked by growing recognition.
World recognition
In 1870, Maxwell was elected an honorary doctor of letters from the University of Edinburgh, in 1874 - a foreign honorary member of the American Academy of Arts and Sciences in Boston, in 1875 - a member of the American Philosophical Society in Philadelphia, and also became an honorary member of the academies of New York, Amsterdam, Vienna . For the next five years, Maxwell spent the next five years editing and preparing for publication twenty sets of Henry Cavendish's manuscripts.In 1877, Maxwell felt the first signs of illness, and in May 1879 he gave his last lecture to his students.
Dimension
In his famous treatise on electricity and magnetism (see Moscow, Nauka, 1989), Maxwell addressed the problem of the dimension of physical quantities and laid the foundations of their kinetic system. The peculiarity of this system is the presence in it of only two parameters: length L and time T. All known (and unknown today!) quantities are represented in it as integer powers of L and T. Fractional indicators appearing in the formulas of dimensions of other systems, devoid of physical content and there is no logical meaning in this system.In accordance with the requirements of J. Maxwell, A. Poincaré, N. Bohr, A. Einstein, V. I. Vernadsky, R. Bartini a physical quantity is universal if and only if its connection with space and time is clearme. And, nevertheless, until J. Maxwell’s treatise “On Electricity and Magnetism” (1873), the connection between the dimension of mass and length and time was not established.
Since the dimension for mass was introduced by Maxwell (along with the notation in the form of square brackets), we allow ourselves to quote an excerpt from the work of Maxwell himself: “Any expression for any quantity consists of two factors or components. One of these is the name of some known quantity of the same type as the quantity we are expressing. She is taken as reference standard. The other component is a number indicating how many times the standard must be applied to obtain the required value. The reference standard quantity is called e unit, and the corresponding number is h and verbal meaning of this value."
“ABOUT MEASUREMENT OF VALUES”
1. Any expression for any quantity consists of two factors or components. One of these is the name of some known quantity of the same type as the quantity we are expressing. She is taken as reference standard. The other component is a number indicating how many times the standard must be applied to obtain the required value. The reference standard value is called in technology Unit, and the corresponding number is Numeric Meaning of this value.
2. When constructing a mathematical system, we consider the basic units - length, time and mass - as given, and we derive all derivative units from them using the simplest acceptable definitions.
Therefore, in all scientific research It is very important to use units belonging to a properly defined system, as well as to know their relationships with the basic units in order to be able to immediately convert the results of one system to another.
Knowing the dimensions of units provides us with a method of verification that should be applied to equations obtained as a result of long-term research.
The dimension of each of the terms of the equation relative to each of the three basic units must be the same. If this is not so, then the equation is meaningless, it contains some kind of error, since its interpretation turns out to be different and depends on the arbitrary system of units that we accept.
Three basic units:
(1) LENGTH. The standard of length used in this country for scientific purposes is the foot, which is one third of the standard yard kept in the Treasury.
In France and other countries that have adopted the metric system, the standard of length is the meter. Theoretically, this is one ten-millionth of the length of the earth's meridian, measured from the pole to the equator; in practice, this is the length of the standard stored in Paris, made by Borda in such a way that at the melting temperature of the ice it corresponds to the value of the meridian length obtained by d'Alembert. Measurements reflecting new and more precise measurements Lands are not included in the meter; on the contrary, the meridian arc itself is calculated in the original meters.
In astronomy, the unit of length is sometimes taken to be the average distance from the Earth to the Sun.
At current state science, the most universal standard of length that could be proposed would be the wavelength of light of a certain type emitted by some widespread substance (for example, sodium), which has clearly identifiable lines in its spectrum. Such a standard would be independent of any change in the size of the earth, and should be adopted by those who hope that their writings will prove more durable than this celestial body.
When working with unit dimensions, we will denote the unit of length as [ L]. If the numerical value of the length is l, then this is understood as a value expressed through a certain unit [ L], so that the entire true length is represented as l [ L].
(2) TIME. In all civilized countries, the standard unit of time is derived from the period of revolution of the Earth around its axis. The sidereal day, or true period of revolution of the Earth, can be established with great accuracy by ordinary astronomical observations, and the average solar day can be calculated from the sidereal day thanks to our knowledge of the length of the year.
The second of mean solar time is adopted as the unit of time in all physical studies.
In astronomy, the unit of time is sometimes taken to be a year. A more universal unit of time could be established by taking the oscillation period of that very light whose wavelength is equal to a unit length.
We will refer to a specific unit of time as [ T], and the numerical measure of time is denoted by t.
(3) MASS. In our country, the standard unit of mass is the reference commercial pound (avoirdupois pound), kept in the Treasury. Often used as a unit, a grain is one 7000th of a pound.
IN metric system The unit of mass is the gram; theoretically this is the mass of a cubic centimeter of distilled water at standard values of temperature and pressure, and in practice it is one thousandth of the standard kilogram stored in Paris *.
But if, as is done in the French system, a certain substance, namely water, is taken as a standard of density, then the unit of mass ceases to be independent, but changes like a unit of volume, i.e. How [ L 3]. If, as in the astronomical system, the unit of mass is expressed through the force of its attraction, then the dimension [ M] turns out to be [ L 3 T-2]".
Maxwell shows that mass can be excluded from the number of basic dimensional quantities. This is achieved through two definitions of the concept “power”:
1) 
and 2) .
Equating these two expressions and considering the gravitational constant to be a dimensionless quantity, Maxwell obtains:
, [M] = [L 3 T 2 ].
Mass turned out to be a space-time quantity. Its dimensions: volume with angular acceleration(or density having the same dimension).
The amount of mass began to satisfy the requirement of universality. It became possible to express all other physical quantities in space-time units of measurement.
In 1965, the article “Kinematic system of physical quantities” by R. Bartini was published in the journal “Reports of the USSR Academy of Sciences” (No. 4). These results have exceptional value for the problem under discussion.
Law of Conservation of Power
Lagrange, 1789; Maxwell, 1855.In general, the law of conservation of power is written as the invariance of power magnitude:
From the total power equationN = P + G it follows that useful power and loss power are projectively inverse, and therefore any change in free energy compensated by changes in power losses under full power control .
The obtained conclusion gives grounds to present the law of conservation of power in the form of a scalar equation:
Where .
The change in the active flow is compensated by the difference between losses and gains into the system.
Thus, the mechanism open system removes the restrictions of closure, and thereby provides the opportunity for further movement of the system. However, this mechanism does not show possible directions of movement - the evolution of systems. Therefore, it must be supplemented by the mechanisms of evolving and non-evolving systems or nonequilibrium and equilibrium.
Bibliography
Vl. Kartsev “The Life of Remarkable People. Maxwell." - M., “Young Guard”, 1974.
James Clerk Maxwell. Articles and speeches. M., “Science”, 1968.
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James Clerk Maxwell (1831-79) - English physicist, creator of classical electrodynamics, one of the founders of statistical physics, organizer and first director (since 1871) of the Cavendish Laboratory, predicted the existence of electromagnetic waves, put forward the idea of the electromagnetic nature of light, established the first statistical law - the law of the distribution of molecules by speed, named after him.
Developing the ideas of Michael Faraday, he created the theory of the electromagnetic field (Maxwell's equations); introduced the concept of displacement current, predicted the existence of electromagnetic waves, and put forward the idea of the electromagnetic nature of light. Installed statistical distribution, named after him. He studied the viscosity, diffusion and thermal conductivity of gases. Maxwell showed that the rings of Saturn consist of separate bodies. Works on color vision and colorimetry (Maxwell disk), optics (Maxwell effect), elasticity theory (Maxwell's theorem, Maxwell-Cremona diagram), thermodynamics, history of physics, etc.
Family. Years of study
James Maxwell was born on June 13, 1831, in Edinburgh. He was the only son of the Scottish nobleman and lawyer John Clerk, who, having inherited the estate of a relative's wife, née Maxwell, added this name to his surname. After the birth of their son, the family moved to Southern Scotland, to their own estate, Glenlar (“Shelter in the Valley”), where the boy spent his childhood.
In 1841, James's father sent him to a school called Edinburgh Academy. Here, at the age of 15, Maxwell wrote his first scientific article, “On Drawing Ovals.” In 1847 he entered the University of Edinburgh, where he studied for three years, and in 1850 he moved to the University of Cambridge, where he graduated in 1854. By this time, James Maxwell was a first-class mathematician with the superbly developed intuition of a physicist.
Creation of the Cavendish Laboratory. Teaching work
After graduating from university, James Maxwell was left at Cambridge to pedagogical work. In 1856 he received a position as professor at Marischal College at the University of Aberdeen (Scotland). In 1860 he was elected a member of the Royal Society of London. In the same year he moved to London, accepting an offer to take up the post of head of the department of physics at King's College, University of London, where he worked until 1865.
Returning to Cambridge University in 1871, Maxwell organized and headed Britain's first specially equipped laboratory for physical experiments, known as the Cavendish Laboratory (named after the English scientist Henry Cavendish). The formation of this laboratory, which at the turn of the 19th-20th centuries. turned into one of the largest centers of world science, Maxwell devoted the last years of his life.
In general, few facts from Maxwell’s life are known. Shy and modest, he sought to live in solitude and did not keep diaries. In 1858 James Maxwell married, but family life, apparently, turned out unsuccessfully, exacerbated his unsociability, and alienated him from his former friends. There is speculation that much of the important material about Maxwell's life was lost in the 1929 fire at his Glenlare home, 50 years after his death. He died of cancer at the age of 48.
Scientific activity
Maxwell's unusually wide sphere of scientific interests covered the theory of electromagnetic phenomena, the kinetic theory of gases, optics, the theory of elasticity and much more. One of his first works was research on the physiology and physics of color vision and colorimetry, begun in 1852. In 1861, James Maxwell first obtained a color image by simultaneously projecting red, green and blue slides onto a screen. This proved the validity of the three-component theory of vision and outlined ways to create color photography. In his works 1857-59, Maxwell theoretically studied the stability of Saturn's rings and showed that Saturn's rings can be stable only if they consist of particles (bodies) that are not connected to each other.
In 1855, D. Maxwell began a series of his main works on electrodynamics. The articles “On Faraday's lines of force” (1855-56), “On physical lines of force” (1861-62), and “Dynamic theory of the electromagnetic field” (1869) were published. The research was completed with the publication of a two-volume monograph, “Treatise on Electricity and Magnetism” (1873).
Creation of the electromagnetic field theory
When James Maxwell began researching electrical and magnetic phenomena in 1855, many of them had already been well studied: in particular, the laws of interaction of stationary electric charges (Coulomb's law) and currents (Ampere's law) had been established; It has been proven that magnetic interactions are interactions of moving electric charges. Most scientists of that time believed that interaction was transmitted instantly, directly through emptiness (the theory of long-range action).
A decisive turn to the theory of short-range action was made by Michael Faraday in the 30s. 19th century According to Faraday's ideas, an electric charge creates an electric field in the surrounding space. The field of one charge acts on another, and vice versa. The interaction of currents is carried out through a magnetic field. Faraday described the distribution of electric and magnetic fields in space using lines of force, which, in his view, resemble ordinary elastic lines in a hypothetical medium - the world ether.
Maxwell fully accepted Faraday's ideas about the existence of an electromagnetic field, that is, about the reality of processes in space near charges and currents. He believed that the body cannot act where it does not exist.
The first thing D.K. did Maxwell - gave Faraday's ideas a strict mathematical form, so necessary in physics. It turned out that with the introduction of the concept of field, the laws of Coulomb and Ampere began to be expressed most fully, deeply and elegantly. In the phenomenon of electromagnetic induction, Maxwell saw a new property of fields: an alternating magnetic field generates in empty space an electric field with closed lines of force (the so-called vortex electric field).
The next and final step in the discovery of the basic properties of the electromagnetic field was taken by Maxwell without any reliance on experiment. He made a brilliant guess that an alternating electric field generates a magnetic field, just like an ordinary electric current (displacement current hypothesis). By 1869, all the basic laws of the behavior of the electromagnetic field were established and formulated in the form of a system of four equations, called Maxwell's equations.
Maxwell's equations are the basic equations of classical macroscopic electrodynamics, describing electromagnetic phenomena in arbitrary media and in vacuum. Maxwell's equations were obtained by J.C. Maxwell in the 60s. 19th century as a result of generalization of the laws of electrical and magnetic phenomena found from experience.
A fundamental conclusion followed from Maxwell's equations: the finiteness of the speed of propagation of electromagnetic interactions. This is the main thing that distinguishes the theory of short-range action from the theory of long-range action. The speed turned out to be equal to the speed of light in vacuum: 300,000 km/s. From this Maxwell concluded that light is a form of electromagnetic waves.
Works on the molecular kinetic theory of gases
The role of James Maxwell in the development and establishment of molecular kinetic theory (the modern name is statistical mechanics) is extremely important. Maxwell was the first to make a statement about the statistical nature of the laws of nature. In 1866 he discovered the first statistical law - the law of the distribution of molecules by speed (Maxwell distribution). In addition, he calculated the viscosity of gases depending on the speeds and mean free path of molecules, and derived a number of thermodynamic relations.
Maxwell's distribution is the velocity distribution of molecules of a system in a state of thermodynamic equilibrium (provided that the translational motion of molecules is described by the laws of classical mechanics). Established by J.C. Maxwell in 1859.
Maxwell was a brilliant popularizer of science. He wrote a number of articles for the Encyclopedia Britannica and popular books: “The Theory of Heat” (1870), “Matter and Motion” (1873), “Electricity in Elementary Exposition” (1881), which were translated into Russian; gave lectures and reports on physical topics for a wide audience. Maxwell also showed great interest in the history of science. In 1879 he published the works of G. Cavendish on electricity, providing them with extensive comments.
Evaluation of Maxwell's work
The scientist's works were not appreciated by his contemporaries. Ideas about the existence of an electromagnetic field seemed arbitrary and unfruitful. Only after Heinrich Hertz experimentally proved the existence of electromagnetic waves predicted by Maxwell in 1886-89 did his theory gain universal acceptance. This happened ten years after Maxwell's death.
After experimental confirmation of the reality of the electromagnetic field, a fundamental scientific discovery was made: there are different types of matter, and each of them has its own laws, which are not reducible to Newton’s laws of mechanics. However, Maxwell himself was hardly clearly aware of this and at first tried to build mechanical models of electromagnetic phenomena.
The American physicist Richard Feynman said excellently about Maxwell’s role in the development of science: “In the history of mankind (if you look at it, say, ten thousand years later), the most significant event of the 19th century will undoubtedly be Maxwell’s discovery of the laws of electrodynamics. Against the backdrop of this important scientific discovery, the American Civil War in the same decade will look like a provincial incident.
James Maxwell has passed away 5 November 1879, Cambridge. He is buried not in the tomb of the great men of England - Westminster Abbey - but in a modest grave next to his beloved church in a Scottish village, not far from family estate.
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MAXWELL, James Clerk
English physicist James Clerk Maxwell was born in Edinburgh into the family of a Scottish nobleman from the noble Clerk family. He studied first at Edinburgh (1847–1850), then at Cambridge (1850–1854) universities. In 1855, Maxwell became a member of the council of Trinity College, in 1856–1860. was a professor at Marischal College, University of Aberdeen, and from 1860 headed the department of physics and astronomy at King's College, University of London. In 1865, due to a serious illness, Maxwell resigned from the department and settled on his family estate of Glenlare near Edinburgh. There he continued to study science and wrote several essays on physics and mathematics. In 1871 he took the chair of experimental physics at the University of Cambridge. Maxwell organized a research laboratory, which opened on June 16, 1874 and was named Cavendish in honor of Henry Cavendish.
Maxwell completed his first scientific work while still at school, inventing a simple way to draw oval shapes. This work was reported at a meeting of the Royal Society and even published in its Proceedings. While a member of the council of Trinity College, he was engaged in experiments on color theory, acting as a continuator of Jung's theory and Helmholtz's theory of the three primary colors. In experiments on color mixing, Maxwell used a special top, the disk of which was divided into sectors painted in different colors (Maxwell disk). When the top rotated quickly, the colors merged: if the disk was painted in the same way as the colors of the spectrum, it appeared white; if one half of it was painted red and the other half yellow, it appeared orange; mixing blue and yellow created the impression of green. In 1860, Maxwell was awarded the Rumford Medal for his work on color perception and optics.
In 1857, the University of Cambridge announced a competition for the best paper on the stability of Saturn's rings. These formations were discovered by Galileo at the beginning of the 17th century. and presented an amazing mystery of nature: the planet seemed surrounded by three continuous concentric rings, consisting of a substance of an unknown nature. Laplace proved that they cannot be solid. After conducting a mathematical analysis, Maxwell became convinced that they could not be liquid, and came to the conclusion that such a structure could only be stable if it consisted of a swarm of unrelated meteorites. The stability of the rings is ensured by their attraction to Saturn and the mutual movement of the planet and meteorites. For this work, Maxwell received the J. Adams Prize.
One of Maxwell's first works was his kinetic theory of gases. In 1859, the scientist gave a report at a meeting of the British Association in which he presented the distribution of molecules by speed (Maxwellian distribution). Maxwell developed the ideas of his predecessor in the development of the kinetic theory of gases by Rudolf Clausius, who introduced the concept of "mean free path". Maxwell proceeded from the idea of a gas as an ensemble of many ideally elastic balls moving chaotically in a closed space. Balls (molecules) can be divided into groups according to speed, while in a stationary state the number of molecules in each group remains constant, although they can leave and enter groups. From this consideration it followed that “particles are distributed by speed according to the same law as observational errors are distributed in the theory of the least squares method, i.e. according to Gaussian statistics." As part of his theory, Maxwell explained Avogadro's law, diffusion, thermal conductivity, internal friction (transfer theory). In 1867 he showed the statistical nature of the second law of thermodynamics.
In 1831, the year Maxwell was born, Michael Faraday carried out the classic experiments that led him to the discovery of electromagnetic induction. Maxwell began to study electricity and magnetism about 20 years later, when there were two views on the nature of electric and magnetic effects. Scientists such as A. M. Ampere and F. Neumann adhered to the concept of long-range action, viewing electromagnetic forces as analogous to the gravitational attraction between two masses. Faraday was an advocate of the idea of lines of force that connect positive and negative electrical charges or the north and south poles of a magnet. Lines of force fill the entire surrounding space (field, in Faraday's terminology) and determine electrical and magnetic interactions. Following Faraday, Maxwell developed a hydrodynamic model of lines of force and expressed the then known relations of electrodynamics in a mathematical language corresponding to Faraday's mechanical models. The main results of this research are reflected in the work “Faraday's Lines of Force” (1857). In 1860–1865 Maxwell created the theory of the electromagnetic field, which he formulated in the form of a system of equations (Maxwell's equations) describing the basic laws of electromagnetic phenomena: the 1st equation expressed Faraday's electromagnetic induction; 2nd – magnetoelectric induction, discovered by Maxwell and based on ideas about displacement currents; 3rd – the law of conservation of electricity; 4th – vortex nature of the magnetic field.
Continuing to develop these ideas, Maxwell came to the conclusion that any changes in the electric and magnetic fields should cause changes in the lines of force that penetrate the surrounding space, i.e. there must be pulses (or waves) propagating in the medium. The speed of propagation of these waves (electromagnetic disturbance) depends on the dielectric and magnetic permeability of the medium and is equal to the ratio of the electromagnetic unit to the electrostatic one. According to Maxwell and other researchers, this ratio is 3·10 10 cm/s, which is close to the speed of light measured seven years earlier by the French physicist A. Fizeau. In October 1861, Maxwell informed Faraday about his discovery: light is an electromagnetic disturbance propagating in a non-conducting medium, i.e. a type of electromagnetic wave. This final stage of research is outlined in Maxwell’s work “The Dynamic Theory of the Electromagnetic Field” (1864), and the result of his work on electrodynamics was summed up in the famous “Treatise on Electricity and Magnetism” (1873).
James Maxwell is a physicist who first formulated the foundations of classical electrodynamics. They are still used today. The famous Maxwell equation is known; it was he who introduced into this science such concepts as displacement current, electromagnetic field, predicted electromagnetic waves, the nature and pressure of light, and made many other important discoveries.
Childhood physicist
Physicist Maxwell was born in the 19th century, in 1831. He was born in Edinburgh, Scotland. The hero of our article came from a family of Clerks; his father owned a family estate in South Scotland. In 1826, he found a wife named Frances Kay, they got married, and 5 years later James was born to them.
In infancy, Maxwell and his parents moved to the Middleby estate, where he spent his childhood, which was greatly overshadowed by the death of his mother from cancer. Even in the first years of his life, he was actively interested in the world around him, was fond of poetry, and was surrounded by so-called “scientific toys.” For example, the predecessor of the “magic disc” cinema.
At the age of 10 he began studying with a home teacher, but this turned out to be ineffective, so in 1841 he moved to Edinburgh to live with his aunt. Here he began attending Edinburgh Academy, which emphasized classical education.
Study at the University of Edinburgh
In 1847, the future physicist James Maxwell began studying here. He studied works on physics, magnetism and philosophy, and carried out numerous laboratory experiments. He was most interested in the mechanical properties of materials. He examined them using polarized light. Physicist Maxwell had this opportunity after his colleague William Nicol gave him two polarizing devices he had assembled himself.
At that time he was making a large number of models made of gelatin, subjected them to deformations, and observed color paintings in polarized light. Comparing his experiments with theoretical research, Maxwell derived many new laws and tested old ones. At that time, the results of this work were extremely important for structural mechanics.
Maxwell in Cambridge
In 1850, Maxwell wants to continue his education, although his father is not enthusiastic about this idea. The scientist goes to Cambridge. There he enters the inexpensive Peterhouse College. The curriculum available there did not satisfy James, and studying at Peterhouse did not provide any prospects.
Only at the end of the first semester did he manage to convince his father and transfer to the more prestigious Trinity College. Two years later he becomes a scholarship student and gets a separate room.
At the same time, Maxwell practically does not engage in scientific activities, reads more and attends lectures by prominent scientists of his time, writes poetry, and participates in the intellectual life of the university. The hero of our article communicates a lot with new people, due to this he compensates for his natural shyness.
Maxwell's daily routine was interesting. From 7 am to 5 pm he worked, then fell asleep. I got up again at 21.30, read, and from two to half past three in the morning I went jogging right in the corridors of the hostel. After that, he went to bed again to sleep until the morning.
Electrical work
While at Cambridge, physicist Maxwell became seriously interested in problems of electricity. He explores magnetic and electrical effects.
By that time, Michael Faraday had put forward the theory of electromagnetic induction, lines of force capable of connecting negative and positive electrical charges. However, Maxwell did not like this concept of action at a distance; his intuition told him that there were contradictions somewhere. So he decided to build mathematical theory, which would combine the results obtained by proponents of long-range action and Faraday's representation. He used the method of analogy and applied the results that William Thomson had previously achieved in analyzing heat transfer processes in solids. Thus, for the first time, he gave a reasoned mathematical justification for how the transmission of electrical action occurs in a certain environment.
Color photographs
In 1856, Maxwell went to Aberdeen, where he soon married. In June 1860, at the Congress of the British Association, which takes place in Oxford, the hero of our article makes an important report on his research in the field of color theory, supporting it with specific experiments using a color box. In the same year he was awarded a medal for his work on combining optics and colors.
In 1861, at the Royal Institution, he provided irrefutable evidence of the correctness of his theory - this is a color photograph, which he had been working on since 1855. No one in the world has ever done this before. He shot the negatives through several filters - blue, green and red. By illuminating the negatives through the same filters, he manages to obtain a color image.
Maxwell's equation
In the biography of James Clerk Maxwell, Thomson also had a strong influence on him. As a result, he comes to the conclusion that magnetism has a vortex nature, and electric current has a translational nature. He creates a mechanical model to demonstrate everything clearly.
The resulting displacement current led to the famous continuity equation that is still used today for electric charge. According to contemporaries, this discovery became Maxwell's most significant contribution to modern physics.
last years of life
Maxwell spent the last years of his life in Cambridge in various administrative positions, becoming president of the Philosophical Society. Together with his students, he studied the propagation of waves in crystals.
Employees who worked with him repeatedly noted that he was as easy to communicate as possible, devoted himself entirely to research, had a unique ability to penetrate into the essence of the problem itself, was very insightful, and at the same time responded adequately to criticism, never aspired to become famous, but at the same time he was capable of very refined sarcasm.
The first symptoms of a serious illness appeared in 1877, when Maxwell was only 46 years old. He began to choke more and more often, it was difficult for him to eat and swallow food, and he experienced severe pain.
After two years, it was very difficult for him to give lectures, speak in public, he got tired very quickly. Doctors noted that his condition was constantly deteriorating. The doctors' diagnosis was disappointing - abdominal cancer. At the end of the year, completely weakened, he returned from Glenlare to Cambridge. Dr. James Paget, famous at that time, tried to ease his suffering.
In November 1879, Maxwell died. The coffin with his body was transported from Cambridge to the family estate, buried next to his parents in the small village cemetery in Parton.
Olympics in honor of Maxwell
The memory of Maxwell is preserved in the names of streets, buildings, astronomical objects, awards and charitable foundations. The Maxwell Physics Olympiad is also held annually in Moscow.
It runs for students from grades 7 to 11 inclusive. For schoolchildren in grades 7-8, the results of the Maxwell Olympiad in Physics are a substitute for the regional and All-Russian stages of the Olympiad for schoolchildren in physics.
To participate in the regional stage, you need to receive a sufficient number of points in the preliminary selection. The regional and final stages of the Maxwell Olympiad in Physics are held in two stages. One of them is theoretical, and the second is experimental.
It is interesting that the tasks of the Maxwell Olympiad in Physics at all stages coincide in level of difficulty with the tests of the final stages of the All-Russian Olympiad for schoolchildren.