Michael Faraday's message is short. Interelectro - biography of Michael Faraday

FARADAY (Faraday) Michael (1791-1867), English physicist, founder of the doctrine of the electromagnetic field, foreign honorary member of the St. Petersburg Academy of Sciences (1830). Discovered the chemical effect of electric current, the relationship between electricity and magnetism, magnetism and light. Discovered (1831) electromagnetic induction - a phenomenon that formed the basis of electrical engineering. Established (1833-34) the laws of electrolysis, named after him, discovered para- and diamagnetism, rotation of the plane of polarization of light in a magnetic field (Faraday effect). Proved identity various types electricity. He introduced the concepts of electric and magnetic fields and expressed the idea of ​​the existence of electromagnetic waves.

Faraday ( Faraday) Michael (22 September 1791, London - 25 August 1867, ibid), English physicist, founder modern concept fields in electrodynamics, the author of a number of fundamental discoveries, including the law of electromagnetic induction, the laws of electrolysis, the phenomenon of rotation of the plane of polarization of light in a magnetic field, one of the first researchers of the effect of a magnetic field on media.

Childhood and youth

Faraday was born into the family of a blacksmith. His older brother Robert was also a blacksmith, who in every possible way encouraged Michael’s thirst for knowledge and at first supported him financially. Faraday's mother, a hardworking, wise, although uneducated woman, lived to see the time when her son achieved success and recognition, and was rightfully proud of him.

The family's modest income did not allow Michael to even graduate from high school, and at the age of thirteen he became an apprentice to the owner of a bookstore and bookbinding workshop, where he was to remain for 10 years. All this time, Faraday was persistently engaged in self-education - he read all the literature on physics and chemistry available to him, repeated the experiments described in books in his home laboratory, and attended private lectures on physics and astronomy in the evenings and Sundays. He received money (a shilling to pay for each lecture) from his brother. At the lectures, Faraday made new acquaintances, to whom he wrote many letters in order to develop a clear and concise style of presentation; he also tried to master the techniques of oratory.

Getting started at the Royal Institution

One of the clients of the bookbindery, a member of the Royal Society of London Denault, noticing Faraday's interest in science, helped him get to the lectures of the outstanding physicist and chemist G. Davy at the Royal Institution. Faraday carefully wrote down and bound the four lectures and sent them along with the letter to the lecturer. This “bold and naive step,” according to Faraday himself, had a decisive influence on his fate. In 1813, Davy (not without some hesitation) invited Faraday to fill the vacant position of assistant at the Royal Institution, and in the fall of the same year he took him on a two-year trip to the scientific centers of Europe. This trip was of great importance for Faraday: he and Davy visited a number of laboratories, met such scientists as A. Ampere, M. Chevreul, J. L. Gay-Lussac, who in turn drew attention to the brilliant abilities of the young Englishman.

First independent research. Scientific publications

After returning to the Royal Institution in 1815, Faraday began intensive work, in which independent scientific research occupied an increasing place. In 1816 he began giving public lectures on physics and chemistry at the Society for Self-Education. In the same year his first printed work appeared.

In 1821, several important events occurred in Faraday's life. He received a position as overseer of the building and laboratories of the Royal Institution (i.e., technical overseer) and published two significant scientific papers (on the rotation of a current around a magnet and a magnet around a current, and on the liquefaction of chlorine). That same year he got married and, as his entire subsequent life showed, he was very happy in his marriage.

In the period until 1821, Faraday published about 40 scientific papers, mainly on chemistry. Gradually, his experimental research increasingly shifted to the field of electromagnetism. After H. Oersted's discovery of the magnetic action of electric current in 1820, Faraday became fascinated by the problem of the connection between electricity and magnetism. In 1822, an entry appeared in his laboratory diary: “Convert magnetism into electricity.” However, Faraday continued other research, including in the field of chemistry. Thus, in 1824 he was the first to obtain chlorine in a liquid state.

Election to the Royal Society. Professorship

In 1824, Faraday was elected a member of the Royal Society, despite the active opposition of Davy, with whom Faraday's relationship had become quite complicated by that time, although Davy liked to repeat that of all his discoveries, the most significant was “Faraday's discovery.” The latter also paid tribute to Davy, calling him a "great man."

A year after his election to the Royal Society, Faraday was appointed director of the laboratory of the Royal Institution, and in 1827 he received a professorship at this institute.

Law of electromagnetic induction. Electrolysis

In 1830, despite the cramped financial situation, Faraday resolutely refuses all side activities, performing any scientific and technical research and other work (except for lecturing on chemistry) in order to devote himself entirely to scientific research. He soon achieved brilliant success: on August 29, 1831 he discovered the phenomenon of electromagnetic induction - the phenomenon of the generation of an electric field by an alternating magnetic field. Ten days of intense work allowed Faraday to comprehensively and completely investigate this phenomenon, which, without exaggeration, can be called the foundation, in particular, of all modern electrical engineering. But Faraday himself was not interested in the applied possibilities of his discoveries; he strove for the main thing - the study of the laws of Nature. The discovery of electromagnetic induction brought Faraday fame. But he was still very strapped for money, so his friends were forced to work to provide him with a lifelong government pension. These efforts were crowned with success only in 1835. When Faraday got the impression that the Minister of the Treasury treated this pension as a sop to the scientist, he sent a letter to the minister in which he respectfully refused any pension. The minister had to apologize to Faraday.

In 1833-34, Faraday studied the passage of electric currents through solutions of acids, salts and alkalis, which led him to the discovery of the laws of electrolysis. These laws (Faraday's laws) subsequently played an important role in the development of ideas about discrete electric charge carriers. Until the end of the 1830s. Faraday carried out extensive research electrical phenomena in dielectrics.

Faraday's disease. Latest experimental work

Constant enormous mental stress undermined Faraday's health and forced him to take a break for five years in 1840. scientific work. Returning to it again, Faraday in 1848 discovered the phenomenon of rotation of the plane of polarization of light propagating in transparent substances along the lines of magnetic field strength (Faraday effect). Apparently, Faraday himself (who excitedly wrote that he “magnetized light and illuminated the magnetic line of force”) attached great importance to this discovery. Indeed, it was the first indication of the existence of a connection between optics and electromagnetism. Conviction in the deep interconnection of electrical, magnetic, optical and other physical and chemical phenomena became the basis of Faraday's entire scientific worldview.

Other experimental works of Faraday at this time were devoted to studies of the magnetic properties of various media. In particular, in 1845 he discovered the phenomena of diamagnetism and paramagnetism.

In 1855, illness again forced Faraday to interrupt his work. He became significantly weaker and began to lose his memory catastrophically. He had to write down everything in the laboratory notebook, down to where and what he put before leaving the laboratory, what he had already done and what he was going to do next. To continue working, he had to give up a lot, including visiting friends; the last thing he gave up was lectures for children.

The importance of scientific works

Even a far from complete list of what Faraday contributed to science gives an idea of ​​the exceptional significance of his works. This list, however, misses the main thing that constitutes Faraday’s enormous scientific merit: he was the first to create a field concept in the doctrine of electricity and magnetism. If before him the idea of ​​direct and instantaneous interaction of charges and currents through empty space prevailed, Faraday consistently developed the idea that the active material carrier of this interaction is the electromagnetic field. D. K. Maxwell, who became his follower, wrote about this beautifully, further developing his teaching and putting ideas about the electromagnetic field into a clear mathematical form: “Faraday, with his mind’s eye, saw the lines of force that lower all space. Where mathematicians saw centers of tension of forces long-range action, Faraday saw an intermediate agent. Where they saw nothing but distance, content with finding the law of distribution of forces acting on electrical fluids, Faraday sought the essence of real phenomena occurring in the medium."

The point of view on electrodynamics from the standpoint of the field concept, the founder of which was Faraday, has become an integral part modern science. Faraday's writings marked the beginning of new era in physics.

“There is no desire more natural than the desire for knowledge.” - M. Montaigne

FARADAY, Michael (1791 - 1867)- outstanding English physicist, founder of the doctrine of the electromagnetic field, foreign honorary member of the St. Petersburg Academy of Sciences (1830). Discovered the chemical effect of electric current, the relationship between electricity and magnetism, magnetism and light. Discovered (1831) the phenomenon of electromagnetic induction. Established (1833-1834) the laws of electrolysis, discovered para- and diamagnetism, rotation of the plane of polarization of light in a magnetic field (Faraday effect).

The journey he took in his youth played a great role in Faraday's life.

In 1813, the Englishman Sir Humphry Davy, together with his promising laboratory assistant and Englishman Michael Faraday, sets out to travel. In Paris, Faraday will meet Ampère, Gay-Lussac, and Humboldt.

Before Faraday's eyes, Davy makes one of his brilliant discoveries in Paris - he recognizes a new chemical element - iodine - in an unknown substance given to him by Ampère. In Genoa - experiments with an electric stingray, Faraday helps Davy find out whether the electric discharge of the stingray causes the decomposition of water. In Florence, the burning of diamond in an oxygen atmosphere and the final proof of the unified nature of diamond and graphite.

Here, with the help of a huge lens, Davy and Faraday direct the rays of the sun onto a diamond lying in a platinum cup under a glass cap filled with oxygen. Faraday recalls: “Today we performed a great experiment by making a diamond burn... When the diamond was removed from the focus of the lens, it continued to burn rapidly. The sparkling diamond glowed with a crimson light turning into purple, and, placed in the darkness, burned for about four more minutes.”

At the Chimento Academy, Faraday and Davy admire the unique exhibits - Galileo's own paper telescope and a magnetic stone that lifts 150 pounds.

In Milan, Faraday saw Volta, who came to Sir G. Davy: “He is a cheerful old man, there is a red ribbon on his chest, and he is very easy to talk.” Faraday begins to speak fluent French and German. But most importantly, during the trip Faraday feels great discoveries flying in the air in electrical engineering. This journey was great school for the future scientist Faraday.

From 1815 to 1820 Faraday was engaged in research in chemistry. A change in his scientific activity occurred in 1820 after becoming familiar with the work of Oersted.

In 1821, Faraday wrote in his diary: "Convert magnetism into electricity." His entire future life was connected with the solution of this problem.

Helmholtz once said about Faraday: " Some wire and several old pieces of wood with iron enable him to make greatest discoveries"

Election to Royal Society Faraday took place in 1824, 11 years after his appointment as a laboratory assistant.

1831 triumphant experiment - as a result of ten years of hard work, Faraday openly phenomenon of electromagnetic induction.

And a little later, Faraday, installing a rotating copper disk between the poles of a magnet, creates the first electric generator.

Punctual and hardworking Michael Faraday named three essential components of scientific work: execution, reporting and publication.

Faraday did not know much mathematics. It was "a mind that never gets bogged down in formulas" according to Einstein.

Maxwell wrote: “He was far from putting his results into mathematical formulas, either those that were approved by the mathematicians of his day, or those that could give rise to new undertakings. Thanks to this, he received the leisure necessary for work. .."

Faraday, back in 1832, left a sealed envelope with the inscription “New views currently to be kept in the archives of the Royal Society” for safekeeping at the Royal Society. In 1938, 106 years later, this envelope was opened in the presence of many English scientists. The words in the sealed envelope shocked everyone: it turns out that Faraday had a clear idea imagine that electric and magnetic fields are also waves.

After the “electromagnetic epic,” Faraday was forced to stop his scientific work for several years - he was so exhausted nervous system constant intense thoughts.

Faraday never spared himself while doing science, he set chemical experiments with harmful mercury. He had useless equipment in his laboratory. “Last Saturday I had another explosion, which again injured my eyes... 13 fragments were taken out of them...” Faraday wrote.

IN last years his strength weakened. He couldn't perform previous works and refused everything that interfered with his pursuit of science. He refuses lectures: “... The time has come to leave due to memory loss and brain fatigue.” Over time, he even gave up letters to friends: “... I tear up my letters because I write nonsense. I can’t smoothly anymore.” write and draw lines. Will I be able to overcome this mess?

Name: Michael Faraday

Age: 75 years old

Activity: experimental physicist, chemist

Family status: was married

Michael Faraday: biography

“As long as people enjoy the benefits of electricity, they will always remember the name of Faraday with gratitude,” said Hermann Helmholtz.

Michael Faraday - English experimental physicist, chemist, creator of the doctrine of the electromagnetic field. He discovered electromagnetic induction, which is the basis industrial production electricity and applications in modern conditions.

Childhood and youth

Michael Faraday was born on September 22, 1791 in Newington Buttes, near London. Father - James Faraday (1761-1810), blacksmith. Mother - Margaret (1764-1838). In addition to Michael, the family included brother Robert and sisters Elizabeth and Margaret. They lived poorly, so Michael did not finish school and at the age of 13 went to work in a bookstore as a delivery boy.

I failed to complete my education. The thirst for knowledge was satisfied by reading books on physics and chemistry - there were plenty of these in the bookstore. The young man mastered his first experiments. He built a current source - a “Leyden jar”. Michael's father and brother encouraged him to experiment.

In 1810, a 19-year-old boy became a member of the philosophical club, where lectures were given on physics and astronomy. Michael was involved in scientific controversy. The gifted young man attracted the attention of the scientific community. Bookstore buyer William Dens gave Michael a gift - a ticket to attend a series of lectures on chemistry and physics by Humphry Davy (founder of electrochemistry, discoverer chemical elements Potassium, Calcium, Sodium, Barium, Boron).

The future scientist, having transcribed Humphry Davy's lectures, bound it and sent it to the professor, accompanied by a letter asking him to find some work at the Royal Institution. Davy took part in the fate of the young man, and after some time, 22-year-old Faraday got a job as a laboratory assistant in a chemical laboratory.

The science

While performing his duties as a laboratory assistant, Faraday did not miss the opportunity to listen to lectures in the preparation of which he participated. Also, with the blessing of Professor Davy, the young man carried out his chemical experiments. His conscientiousness and skill in performing his work as a laboratory assistant made him Davy's constant assistant.

In 1813, Davy took Faraday as his secretary on a two-year European trip. During the trip, the young scientist met the luminaries of world science: Andre-Marie Ampère, Joseph Louis Gay-Lussac, Alessandro Volta.

On his return to London in 1815, Faraday was given the position of assistant. At the same time, he continued what he loved - he conducted his own experiments. During his life, Faraday conducted 30,000 experiments. In scientific circles, for his pedantry and hard work, he received the title of “king of experimenters.” The description of each experience was carefully recorded in diaries. Later, in 1931, these diaries were published.

Faraday's first printed edition was published in 1816. By 1819, 40 works were published. The works are devoted to chemistry. In 1820, from a series of experiments with alloys, a young scientist discovered that alloying steel with the addition of nickel did not oxidize. But the results of the experiments passed by the metallurgists. Opening of stainless steel was patented much later.

In 1820 Faraday became technical superintendent of the Royal Institution. By 1821, he moved from chemistry to physics. Faraday acted as an established scientist and gained weight in the scientific community. An article was published about the principle of operation of an electric motor, which marked the beginning of industrial electrical engineering.

Electromagnetic field

In 1820, Faraday became interested in experiments on the interaction of electricity and magnetic fields. At this point, the concept of “source” was discovered direct current"(A. Volt), "electrolysis", " electric arc", "electromagnet". During this period, electrostatics and electrodynamics developed, and the experiments of Biot, Savart, and Laplace on working with electricity and magnetism were published. A. Ampere's work on electromagnetism was published.

In 1821, Faraday’s work “On Some New Electromagnetic Motions and the Theory of Magnetism” was published. In it, the scientist presented experiments with a magnetic needle rotating around one pole, i.e., he carried out the transformation electrical energy to mechanical. In fact, he introduced the world's first, albeit primitive, Electrical engine.

The joy of discovery was spoiled by the complaint of William Wollaston (discovered Palladium, Rhodium, designed a refractometer and goniometer). In a complaint to Professor Davy, the scientist accused Faraday of stealing the idea of ​​a rotating magnetic needle. The story took on a scandalous character. Davy accepted Wollaston's position. Only a personal meeting between the two scientists and Faraday explaining his position was able to resolve the conflict. Wollaston abandoned the claim. The relationship between Davy and Faraday lost its former trust. Although the first one is up last days He never tired of repeating that Faraday was the main discovery he made.

In January 1824, Faraday was elected a member of the Royal Society of London. Professor Davy voted against.

In 1823 he became a corresponding member of the Paris Academy of Sciences.

In 1825, Michael Faraday took Davy's place as director of the Royal Institution's Laboratory of Physics and Chemistry.

After the discovery of 1821, the scientist did not publish works for ten years. In 1831 he became professor of Woolwich (military academy), and in 1833 - professor of chemistry at the Royal Institution. He conducted scientific debates and gave lectures at scientific meetings.

Back in 1820, Faraday became interested in the experiment of Hans Oersted: movement along an electric current circuit caused the movement of a magnetic needle. Electric current caused the emergence of magnetism. Faraday suggested that, accordingly, magnetism could be the cause of electric current. The first mention of the theory appeared in the scientist’s diary in 1822. It took ten years of experiments to unravel the mystery of electromagnetic induction.

Victory came on August 29, 1831. The device that allowed Faraday to make his ingenious discovery consisted of an iron ring and many turns of copper wire wound around its two halves. In the circuit of one half of the ring, closed by a wire, there was a magnetic needle. The second winding was connected to the battery. When the current was turned on, the magnetic needle oscillated in one direction, and when turned off, in the other. Faraday concluded that a magnet was capable of converting magnetism into electrical energy.

The phenomenon of “the appearance of an electric current in a closed circuit when the magnetic flux passing through it changes” was called electromagnetic induction. The discovery of electromagnetic induction paved the way for the creation of a current source - an electric generator.

The discovery marked the beginning of a new fruitful round of the scientist’s experiments, which gave the world “Experimental Research on Electricity.” Faraday empirically proved the uniform nature of the generation of electrical energy, independent of the method by which the electric current is generated.

In 1832, the physicist was awarded the Copley Medal.

Faraday became the author of the first transformer. He owns the concept of “dielectric constant”. In 1836, through a series of experiments, he proved that the charge of the current affects only the shell of the conductor, leaving the objects inside it untouched. In applied science, a device made on the principle of this phenomenon is called a “Faraday cage”.

Discoveries and works

Michael Faraday's discoveries are not only about physics. In 1824 he discovered benzene and isobutylene. The scientist developed a liquid form of chlorine, hydrogen sulfide, carbon dioxide, ammonia, ethylene, nitrogen dioxide, and obtained the synthesis of hexachlorane.

In 1835, Faraday was forced to take a two-year break from work due to illness. The cause of the disease was suspected to be the scientist’s contact during experiments with mercury vapor. Having worked for a short time after recovery, in 1840 the professor again felt unwell. I was plagued by weakness and temporary memory loss. The recovery period dragged on for 4 years. In 1841, at the insistence of doctors, the scientist went on a trip to Europe.

The family lived almost in poverty. According to Faraday's biographer John Tyndall, the scientist received a pension of 22 pounds a year. In 1841, Prime Minister William Lamb, Lord Melbourne, under public pressure, signed a decree granting Faraday a state pension of £300 per year.

In 1845, the great scientist managed to attract the attention of the world community with some more discoveries: the discovery of a change in the plane of polarized light in a magnetic field (“Faraday effect”) and diamagnetism (magnetization of a substance to an external magnetic field acting on it).

The government of England more than once asked Michael Faraday for help in solving problems related to technical issues. The scientist developed a program for equipping lighthouses, methods to combat ship corrosion, and acted as a forensic expert. Being a good-natured and peace-loving person by nature, he flatly refused to participate in the creation of chemical weapons for the war with Russia in Crimean War.

In 1848 she gave Faraday a house on the left bank of the Thames, Hampton Court. The British Queen paid expenses and taxes for the household. The scientist and his family moved into it, leaving business in 1858.

Personal life

Michael Faraday was married to Sarah Barnard (1800-1879). Sarah is the sister of Faraday's friend. The 20-year-old girl did not immediately accept the marriage proposal - the young scientist had to worry. The quiet wedding took place on June 12, 1821. Many years later Faraday wrote:

“I got married - an event that, more than any other, contributed to my happiness on earth and my healthy state of mind.”

Faraday's family, like his wife's family, are members of the Sandemanian Protestant community. Faraday performed the work of deacon of the London community and was repeatedly elected as an elder.

Death

Michael Faraday was ill. In brief moments, when the illness subsided, he worked. In 1862 he put forward a hypothesis about the movement of spectral lines in a magnetic field. Peter Zeeman was able to confirm the theory in 1897, for which he received the Nobel Prize in 1902. Zeeman named Faraday as the author of the idea.

Michael Faraday died at his desk on August 25, 1867, aged 75. He was buried next to his wife in Highgate Cemetery in London. Before his death, the scientist asked for a modest funeral, so only relatives came. The name of the scientist and the years of his life are carved on the gravestone.

• In his work, the physicist did not forget about children. Lectures for children “The History of a Candle” (1961) are republished to this day.
• Faraday's portrait appears on the British £20 note issued in 1991-1999.
• There were rumors that Davy did not respond to Faraday's request for work. One day, having temporarily lost his sight during a chemical experiment, the professor remembered the persistent young man. After working as a scientist's secretary, the young man so impressed Davy with his erudition that he offered Michael a job in the laboratory.
• After returning from a European tour with Davy's family, Faraday worked as a dishwasher while waiting for an assistantship at the Royal Institution.

September 22, 2011 marked the 220th anniversary of the birth of Michael Faraday (1791–1867), an English experimental physicist who introduced the concept of “field” into science and laid the foundations for the concept of the physical reality of electric and magnetic fields. These days, the concept of a field is familiar to any high school student. Basic information about electric and magnetic fields and methods of describing them using lines of force, tensions, potentials, etc. have long been included in school textbooks on physics. In the same textbooks you can read that a field is a special form of matter, fundamentally different from matter. But with an explanation of what exactly this “specialness” consists of, serious difficulties arise. Naturally, textbook authors cannot be blamed for this. After all, if the field is not reducible to some other, simpler entities, then there is nothing to explain. You just need to accept the physical reality of the field as an experimentally established fact and learn to work with the equations that describe the behavior of this object. For example, Richard Feynman calls for this in his Lectures, noting that scientists for a long time tried to explain the electromagnetic field using various mechanical models, but then abandoned this idea and considered that only the system of famous Maxwell’s equations describing the field had a physical meaning.

Does this mean that we should completely give up trying to understand what a field is? It seems that significant assistance in answering this question can be provided by acquaintance with “Experimental Studies in Electricity” by Michael Faraday - a grandiose three-volume work that the brilliant experimenter created for more than 20 years. It is here that Faraday introduces the concept of a field and, step by step, develops the idea of ​​the physical reality of this object. It is important to note that Faraday’s “Experimental Investigations” - one of the greatest books in the history of physics - is written in excellent language, does not contain a single formula and is quite accessible to schoolchildren.

Field introduction. Faraday, Thomson and Maxwell

The term “field” (more precisely: “magnetic field”, “field of magnetic forces”) was introduced by Faraday in 1845 during research into the phenomenon of diamagnetism (the terms “diamagnetism” and “paramagnetism” were also introduced by Faraday) - the effect of weak repulsion by a magnet discovered by the scientist a number of substances. Initially, the field was considered by Faraday as a purely auxiliary concept, essentially a coordinate grid formed by magnetic power lines and used to describe the nature of the movement of bodies near magnets. Thus, pieces of diamagnetic substances, for example bismuth, moved from areas of condensation of field lines to areas of their rarefaction and were located perpendicular to the direction of the lines.

Somewhat later, in 1851–1852, when mathematically describing the results of some of Faraday’s experiments, the term “field” was occasionally used by the English physicist William Thomson (1824–1907). As for the creator of the theory electromagnetic field James Clerk Maxwell (1831–1879), then in his works the term “field” also practically does not appear at first and is used only to designate that part of space in which one can detect magnetic forces. Only in the work “Dynamic Theory of the Electromagnetic Field” published in 1864–1865, in which the system of “Maxwell’s equations” first appears and predicts the possibility of the existence of electromagnetic waves propagating at the speed of light, is the field spoken of as a physical reality.

This is the brief history of the introduction of the concept of “field” into physics. It is clear from it that initially this concept was considered as a purely auxiliary one, denoting simply that part of space (it can be unlimited) in which magnetic forces can be detected and their distribution can be depicted using lines of force. (Term " electric field"became used only after Maxwell created the theory of the electromagnetic field.)

It is important to emphasize that neither the lines of force known to physicists before Faraday, nor the field “consisting” of them were considered (and could not be considered!) by the scientific community of the 19th century as a physical reality. Attempts by Faraday to talk about the materiality of lines of force (or Maxwell - about the materiality of the field) were perceived by scientists as completely unscientific. Even Thomson, an old friend of Maxwell, who himself did a lot to develop the mathematical foundations of field physics (it was Thomson, and not Maxwell, who was the first to show the possibility of “translating” the language of Faraday’s force lines into the language of partial differential equations), called the theory of the electromagnetic field “mathematical nihilism” "and for a long time refused to recognize it. It is clear that Thomson could only do this if he had very serious reasons for doing so. And he had such reasons.

Force field and Newton's force

The reason why Thomson could not accept the reality of force lines and fields is simple. The lines of force of the electric and magnetic fields are defined as continuous lines drawn in space so that the tangents to them at each point indicate the directions of the electric and magnetic forces acting at that point. The magnitudes and directions of these forces are calculated using the laws of Coulomb, Ampere and Biot-Savart-Laplace. However, these laws are based on the principle of long-range action, which allows for the possibility of instantaneous transmission of the action of one body to another over any distance and, thereby, excluding the existence of any material intermediaries between interacting charges, magnets and currents.

It should be noted that many scientists were skeptical about the principle that bodies could somehow mysteriously act where they do not exist. Even Newton, who was the first to use this principle when deriving the law universal gravity, believed that some kind of substance could exist between interacting bodies. But the scientist did not want to build a hypothesis about it, preferring to develop mathematical theories of laws based on firmly established facts. Newton's followers did the same. According to Maxwell, they literally “swept out of physics” all sorts of invisible atmospheres and outflows with which proponents of the concept of short-range action surrounded magnets and charges in the 18th century. Nevertheless, in physics of the 19th century, interest in seemingly forever forgotten ideas is gradually beginning to revive.

One of essential preconditions This revival began with problems that arose when trying to explain new phenomena - primarily the phenomena of electromagnetism - on the basis of the principle of long-range action. These explanations became increasingly artificial. Thus, in 1845, the German physicist Wilhelm Weber (1804–1890) generalized Coulomb’s law, introducing into it terms that determine the dependence of the interaction force electric charges on their relative speeds and accelerations. The physical meaning of such a dependence was not clear, and Weber’s additions to Coulomb’s law were clearly in the nature of a hypothesis introduced to explain the phenomena of electromagnetic induction.

In the mid-19th century, physicists increasingly realized that in studying the phenomena of electricity and magnetism, experiment and theory began to speak different languages. In principle, scientists were ready to agree with the idea of ​​the existence of a substance that transmits the interaction between charges and currents at a finite speed, but they could not accept the idea of ​​​​the physical reality of the field. First of all, because of the internal contradiction of this idea. The fact is that in Newtonian physics force is introduced as the cause of the acceleration of a material point. Its (force) magnitude is equal, as is known, to the product of the mass of this point and the acceleration. Thus, force as a physical quantity is determined at the point and at the moment of its action. “Newton himself reminds us,” wrote Maxwell, “that a force exists only as long as it acts; its effect may persist, but the force itself as such is essentially a transitory phenomenon.”

By trying to consider the field not as a convenient illustration of the nature of the distribution of forces in space, but as a physical object, scientists came into conflict with the original understanding of force on the basis of which this object was built. At each point, the field is determined by the magnitude and direction of the force acting on the test body (charge, magnetic pole, coil with current). In essence, the field “consists” only of forces, but the force at each point is calculated on the basis of laws according to which it is meaningless to talk about the field as a physical state or process. The field, considered as a reality, would mean the reality of forces existing outside of any action, which is completely contrary to the original definition of force. Maxwell wrote that in cases where we talk about “conservation of force”, etc., it would be better to use the term “energy”. This is certainly correct, but what is the energy of the field? By the time Maxwell wrote the above lines, he already knew that the energy density of, for example, an electric field is proportional to the square of the intensity of this field, i.e., again, the force distributed in space.

The concept of instantaneous action at a distance is inextricably linked with Newton’s understanding of force. After all, if one body acts on another, distant one, not instantly (essentially destroying the distance between them), then we will have to consider the force moving in space and decide what “part” of the force causes the observed acceleration and what meaning then has the concept "force". Or we must assume that the movement of force (or field) occurs in some special way that does not fit into the framework of Newtonian mechanics.

In 1920, in the article “Ether and the Theory of Relativity,” Albert Einstein (1879–1955) wrote that, speaking about the electromagnetic field as a reality, we must assume the existence of a special physical object, which in principle cannot be imagined as consisting of particles, the behavior of each of which is subject to study over time. Einstein later described the creation of the theory of the electromagnetic field as the greatest revolution in our views on the structure of physical reality since Newton. Thanks to this revolution, physics, along with ideas about the interaction of material points, included ideas about fields as irreducible entities to anything else.

But how was this change in views on reality possible? How did physics manage to go beyond its boundaries and “see” something that simply did not exist for it as a reality before?

Faraday's many years of experiments with power lines played an extremely important role in preparing this revolution. Thanks to Faraday, these lines, well known to physicists, turned from a way of depicting the distribution of electric and magnetic forces in space into a kind of “bridge”, moving along which it was possible to penetrate into the world that was, as it were, “behind the force”, into a world in which forces became manifestations of properties fields. It is clear that such a transformation required a very special kind of talent, the talent that Michael Faraday possessed.

Great Experimenter

Michael Faraday was born on September 22, 1791 into the family of a London blacksmith, who, due to lack of funds, were unable to provide their children with an education. Michael - the third child in the family - did not finish and primary school and at the age of 12 he was apprenticed to a bookbinding workshop. There he had the opportunity to read many books, including popular science, filling in the gaps in his education. Soon Faraday began to visit public lectures, which were regularly held in London to disseminate knowledge among the general public.

In 1812, one of the members of the Royal Society of London, who regularly used the services of a bookbindery, invited Faraday to listen to lectures by the famous physicist and chemist Humphry Davy (1778–1829). This moment became a turning point in Faraday's life. The young man became completely interested in science, and since his time in the workshop was ending, Faraday took the risk of writing to Davy about his desire to engage in research, enclosing carefully bound lecture notes from the scientist to the letter. Davy, who was himself the son of a poor woodcarver, not only responded to Faraday's letter, but also offered him a position as an assistant at the Royal Institution of London. So it began scientific activity Faraday, which continued almost until his death, which occurred on August 25, 1867.

The history of physics knows many outstanding experimenters, but, perhaps, only Faraday was called an Experimenter with a capital letter. And it’s not just his colossal achievements, including the discoveries of the laws of electrolysis and the phenomena of electromagnetic induction, studies of the properties of dielectrics and magnets, and much more. Often important discoveries were made more or less by accident. The same cannot be said about Faraday. His research has always been strikingly systematic and purposeful. So, in 1821, Faraday wrote in his work diary that he was beginning a search for the connection between magnetism and electricity and optics. He discovered the first connection 10 years later (the discovery of electromagnetic induction), and the second - 23 years later (the discovery of the rotation of the plane of polarization of light in a magnetic field).

Faraday's Experimental Studies in Electricity contains about 3,500 paragraphs, many of which contain descriptions of experiments he performed. And this is only what Faraday saw fit to publish. In Faraday's multi-volume Diaries, which he kept since 1821, about 10 thousand experiments are described, and the scientist carried out many of them without anyone's help. Interestingly, in 1991, when the scientific world celebrated the 200th anniversary of Faraday's birth, English historians of physics decided to repeat some of his most famous experiments. But even simply reproducing each of these experiments required a team of modern specialists at least a day of work.

Speaking about Faraday's merits, we can say that his main achievement was the transformation of experimental physics into an independent field of research, the results of which can often be many years ahead of the development of theory. Faraday considered the desire of many scientists to move as quickly as possible from the data obtained in experiments to their theoretical generalization as extremely unproductive. It seemed more fruitful to Faraday to maintain a long-term connection with the phenomena being studied in order to be able to analyze in detail all their features, regardless of whether these features correspond to accepted theories or not.

Faraday extended this approach to the analysis of experimental data to the well-known experiments on aligning iron filings along magnetic field lines. Of course, the scientist knew very well that the patterns that form iron filings can easily be explained on the basis of the principle of long-range action. However, Faraday believed that in this case experimenters should proceed not from concepts invented by theorists, but from phenomena that, in his opinion, indicate the existence in the space surrounding magnets and currents of certain states that are ready for action. In other words, lines of force, according to Faraday, indicated that force should be thought of not only as an action (on a material point), but also as the ability to act.

It is important to emphasize that, following his methodology, Faraday did not try to put forward any hypotheses about the nature of this ability to act, preferring to gradually accumulate experience while working with lines of force. This work began in his studies of the phenomena of electromagnetic induction.

Delayed opening

In many textbooks and reference books you can read that on August 29, 1831, Faraday discovered the phenomenon of electromagnetic induction. Historians of science are well aware that dating discoveries is complex and often quite confusing. The discovery of electromagnetic induction is no exception. From Faraday's Diaries it is known that he observed this phenomenon back in 1822 during experiments with two conducting circuits placed on a soft iron core. The first circuit was connected to a current source, and the second to a galvanometer, which recorded the occurrence of short-term currents when the current in the first circuit was turned on or off. Later it turned out that similar phenomena were observed by other scientists, but, like Faraday at first, they considered them an experimental error.

The fact is that in searching for the phenomena of the generation of electricity by magnetism, scientists were aimed at discovering stable effects, similar, for example, to the phenomenon of the magnetic action of current discovered by Oersted in 1818. Faraday was saved from this general “blindness” by two circumstances. Firstly, close attention to any natural phenomena. In his articles, Faraday reported on both successful and unsuccessful experiments, believing that an unsuccessful experiment (which did not detect the desired effect), but a meaningful experiment also contained some information about the laws of nature. Secondly, shortly before the discovery, Faraday experimented a lot with capacitor discharges, which undoubtedly sharpened his attention to short-term effects. Regularly reviewing his diaries (for Faraday this was a constant part of his research), the scientist, apparently, took a fresh look at the experiments of 1822 and, having reproduced them, realized that he was dealing not with interference, but with the phenomenon he was looking for. The date of this realization was August 29, 1831.

Next, intensive research began, during which Faraday discovered and described the basic phenomena of electromagnetic induction, including the occurrence of induced currents during the relative motion of conductors and magnets. Based on these studies, Faraday came to the conclusion that the decisive condition for the occurrence of induced currents is precisely intersection a conductor of lines of magnetic force, and not a transition to areas of greater or lesser forces. In this case, for example, the occurrence of a current in one conductor when the current is turned on in another, located nearby, Faraday also explained as a result of the conductor crossing power lines: “magnetic curves seem to move (so to speak) across the induced wire, starting from the moment when they begin to develop, and up to the moment when the magnetic current reaches highest value; they seem to spread to the sides of the wire and, therefore, find themselves in relation to the stationary wire in the same position as if it were moving in the opposite direction across them.”

Let us pay attention to how many times in the above passage Faraday uses the words “as if”, and also to the fact that he does not yet have the usual quantitative formulation of the law of electromagnetic induction: the current strength in a conducting circuit is proportional to the rate of change in the number of magnetic lines of force passing through this circuit. A formulation close to this appears in Faraday only in 1851, and it applies only to the case of the movement of a conductor in a static magnetic field. According to Faraday, if a conductor moves in such a field at a constant speed, then the strength of the electric current arising in it is proportional to this speed, and the amount of electricity set in motion is proportional to the number of magnetic field lines crossed by the conductor.

Faraday's caution in formulating the law of electromagnetic induction is due, first of all, to the fact that he could correctly use the concept of a line of force only in relation to static fields. In the case of variable fields, this concept acquired a metaphorical character, and continuous clauses “as if” when we're talking about about moving lines of force show that Faraday understood this very well. He also could not help but take into account the criticism of those scientists who pointed out to him that a line of force is, strictly speaking, a geometric object, the movement of which is simply pointless to talk about. In addition, in experiments we deal with charged bodies, current-carrying conductors, etc., and not with abstractions like lines of force. Therefore, Faraday had to show that when studying at least some classes of phenomena, one cannot limit oneself to considering current-carrying conductors and not take into account the space surrounding them. Thus, in a work devoted to the study of self-induction phenomena, without ever mentioning lines of force, Faraday builds a story about his experiments in such a way that the reader gradually comes to the conclusion that the real cause of the observed phenomena is not current-carrying conductors, but something located in the space surrounding them.

The field is like a premonition. Research into self-induction phenomena

In 1834, Faraday published the ninth part of his Experimental Investigations, which was entitled “On the inductive influence of an electric current on itself and on the inductive action of currents in general.” In this work, Faraday examined the phenomena of self-induction, discovered in 1832 by the American physicist Joseph Henry (1797–1878), and showed that they represent a special case of the phenomena of electromagnetic induction he had previously studied.

Faraday begins his work by describing a series of phenomena, consisting in the fact that when an electrical circuit containing long conductors or an electromagnet winding is opened, a spark appears at the point where the contact is broken, or an electric shock is felt if the contact is separated by hand. At the same time, Faraday points out, if the conductor is short, then no tricks can be used to get a spark or electric shock fails. Thus, it became clear that the occurrence of a spark (or impact) depends not so much on the strength of the current flowing through the conductor before the contact was broken, but on the length and configuration of this conductor. Therefore, Faraday first of all seeks to show that, although the initial cause of the spark is current (if there was no current in the circuit at all, then, naturally, there will be no spark), the strength of the current is not decisive. To do this, Faraday describes a sequence of experiments in which the length of the conductor is first increased, resulting in a stronger spark despite the weakening of the current in the circuit due to the increased resistance. This conductor is then twisted so that current flows only through a small part of it. The current strength increases sharply, but the spark disappears when the circuit is opened. Thus, neither the conductor itself nor the strength of the current in it can be considered as the cause of the spark, the magnitude of which, as it turns out, depends not only on the length of the conductor, but also on its configuration. So, when the conductor is rolled into a spiral, as well as when an iron core is introduced into this spiral, the spark size also increases.

In continuation of the study of these phenomena, Faraday connected an auxiliary short conductor parallel to the place where the contact was opened, the resistance of which was significantly greater than that of the main conductor, but less than that of the spark gap or the body of the person opening the contact. As a result, the spark disappeared when the contact was opened, and a strong short-term current arose in the auxiliary conductor (Faraday calls it an extra current), the direction of which turned out to be opposite to the direction of the current that would flow through it from the source. “These experiments,” writes Faraday, “establish a significant difference between the primary or exciting current and the extra current in relation to quantity, intensity and even direction; they led me to the conclusion that the extracurrent is identical with the induced current I described earlier.”

Having put forward the idea of ​​a connection between the phenomena being studied and the phenomena of electromagnetic induction, Faraday then carried out a series of ingenious experiments confirming this idea. In one of these experiments, next to a spiral connected to a current source, another open spiral was placed. When disconnected from the current source, the first spiral gave a strong spark. However, if the ends of the other spiral were closed, the spark practically disappeared, and a short-term current arose in the second spiral, the direction of which coincided with the direction of the current in the first spiral if the circuit was opened, and was opposite to it if the circuit was closed.

Having established the connection between the two classes of phenomena, Faraday was able to easily explain the experiments performed earlier, namely, the intensification of the spark when the conductor is lengthened, folded into a spiral, an iron core is introduced into it, etc.: “If you observe the inductive effect of a wire one foot long on a located there is a wire nearby that is also one foot long, then it turns out to be very weak; but if the same current be passed through a wire fifty feet long, it will induce in the next fifty feet of wire, at the moment of making or breaking a contact, a much stronger current, as if every extra foot of wire contributed something to the total effect; By analogy, we conclude that the same phenomenon must also occur when the connecting conductor simultaneously serves as a conductor in which an induced current is formed.” Therefore, Faraday concludes, increasing the length of the conductor, rolling it into a spiral and introducing a core into it strengthens the spark. The action of the demagnetizing core is added to the action of one turn of the spiral on another. Moreover, the totality of such actions can compensate for each other. For example, if you fold a long insulated wire, then due to the opposite inductive actions of its two halves, the spark will disappear, although in a straightened state this wire gives a strong spark. The replacement of an iron core with a steel core, which demagnetizes very slowly, also led to a significant weakening of the spark.

So, taking the reader through detailed descriptions sets of experiments performed, Faraday, without saying a word about the field, formed in him, the reader, the idea that the decisive role in the phenomena being studied does not belong to current-carrying conductors, but to some state of magnetization created by them in the surrounding space, or more precisely, speed changes in this state. However, the question of whether this state really exists and whether it can be the subject of experimental research remained open.

The problem of the physical reality of force lines

Faraday managed to take a significant step in proving the reality of field lines in 1851, when he came up with the idea of ​​​​generalizing the concept of a field line. “A magnetic line of force,” Faraday wrote, “may be defined as the line which a small magnetic needle describes when it is moved in one direction or another along the direction of its length, so that the needle remains tangent to the motion all the time; or, in other words, this is the line along which a transverse wire can be moved in any direction and no tendency to generate any current will appear in the latter, whereas when moving it in any other direction such a tendency exists.”

The field line was thus determined by Faraday based on two various laws(and understanding) of the action of magnetic force: its mechanical action on the magnetic needle and its ability (in accordance with the law of electromagnetic induction) to generate electric force. This double definition of the line of force seemed to “materialize” it, giving it the meaning of special, experimentally detectable directions in space. Therefore, Faraday called such lines of force “physical,” believing that he could now definitively prove their reality. A conductor in such a double definition could be imagined as closed and sliding along the lines of force so that, while constantly deforming, it does not intersect the lines. This conductor would highlight a certain conditional “number” of lines that are preserved when they are “condensed” or “rarefied.” Such a sliding of a conductor in a field of magnetic forces without the emergence of an electric current in it could be considered as experimental proof of the conservation of the number of lines of force as they “spread,” for example, from the pole of a magnet, and, thus, as proof of the reality of these lines.

Of course, it is almost impossible to move a real conductor so that it does not cross the power lines. Therefore, Faraday justified the hypothesis about the conservation of their number differently. Let a magnet with pole N and a conductor abcd arranged so that they can rotate relative to each other around an axis ad(Fig. 1; drawing made by the author of the article based on Faraday’s drawings). In this case, part of the conductor ad passes through a hole in the magnet and has free contact at the point d. Loose contact made and on point c, so the plot bc can rotate around a magnet without breaking the electrical circuit connected at the points a And b(also through sliding contacts) to the galvanometer. Conductor bc at full rotation around an axis ad intersects all lines of force emanating from the pole of the magnet N. Now let the conductor rotate at a constant speed. Then, comparing the readings of the galvanometer at different positions of the rotating conductor, for example in the position abcd And pregnant ab"c"d, when the conductor once again crosses all lines of force in a full turn, but in places where they are more rarefied, you can find that the galvanometer readings are the same. According to Faraday, this indicates the preservation of a certain conditional number of lines of force that can characterize the north pole of a magnet (the larger this “quantity,” the stronger the magnet).

Rotating in his installation (Fig. 2; Faraday's drawing) not a conductor, but a magnet, Faraday comes to the conclusion that the number of lines of force in the internal region of the magnet is conserved. Moreover, his reasoning is based on the assumption that the lines of force are not carried away by a rotating magnet. These lines remain “in place” and the magnet rotates among them. In this case, the current is the same in magnitude as when the external conductor rotates. Faraday explains this result by saying that although the outer part of the conductor does not intersect the lines, its inner part (CD), rotating with the magnet, intersects all the lines passing inside the magnet. If the outer part of the conductor is fixed and rotated together with the magnet, then no current arises. This can also be explained. Indeed, the inner and outer parts of the conductor cross the same number of lines of force directed in the same direction, so the currents induced in both parts of the conductor cancel each other out.

From the experiments it followed that inside the magnet the lines of force do not go from the north pole to the south, but on the contrary, forming closed curves with the external lines of force, which allowed Faraday to formulate the law of conservation of the number of magnetic lines of force in the external and internal spaces permanent magnet: “By this astonishing distribution of forces, which is revealed by the moving conductor, the magnet exactly resembles an electromagnetic coil, both in that the lines of force flow in the form of closed circles, and in the equality of their sum inside and outside.” Thus, the concept of “number of power lines” received citizenship rights, due to which the formulation of the law of proportionality of the electromotive force of induction to the number of power lines crossed by a conductor per unit time acquired physical meaning.

However, Faraday admitted that his results were not conclusive proof of the reality of field lines. For such a proof, he wrote, it is necessary to “establish the relationship of the lines of force to time,” that is, to show that these lines can move in space with a finite speed and, therefore, can be detected by some physical methods.

It is important to emphasize that for Faraday the problem of “physical lines of force” had nothing in common with attempts to directly detect ordinary lines of force. Since the discovery of electromagnetic induction, Faraday believed that both ordinary lines of force and the laws of electromagnetism are manifestations of some special properties of matter, its special state, which the scientist called electrotonic. At the same time, the question of the essence of this state and its connection with known forms of matter was, Faraday believed, open: “What this state is and what it depends on, we cannot say now. Perhaps it is conditioned by the ether, like a light ray... Perhaps this is a state of tension, or a state of vibration, or some other state similar electric current, with which magnetic forces are so closely related. Whether the presence of matter is necessary to maintain this state depends on what is meant by the word “matter.” If the concept of matter is limited to weighty or gravitating substances, then the presence of matter is as little significant for the physical lines of magnetic force as for the rays of light and heat. But if, admitting the ether, we accept that this is a kind of matter, then the lines of force can depend on any of its actions.”

Such close attention that Faraday paid to the lines of force was due primarily to the fact that he saw in them a bridge leading to some completely new world. However, it was difficult for even such a brilliant experimenter as Faraday to cross this bridge. Actually, this problem did not allow for a purely experimental solution at all. However, one could try to penetrate mathematically into the space between the lines of force. This is exactly what Maxwell did. His famous equations became the tool that made it possible to penetrate into the non-existent gaps between Faraday's field lines and, as a result, discover a new physical reality there. But this is another story - the story of the Great Theorist.

This refers to the book by R. Feynman, R. Leighton and M. Sands “Feynman Lectures on Physics” (M.: Mir, 1967) ( Note ed.)
In Russian translation, the first volume of this book was published in 1947, the second in 1951, and the third in 1959 in the series “Classics of Science” (M.: Publishing House of the USSR Academy of Sciences). ( Note ed.)
In 1892, William Thomson was awarded the title of nobility "Lord Kelvin" for his fundamental work in various fields of physics, in particular the laying of the transatlantic cable connecting England and the United States.

- a great English physicist, whose outstanding discoveries were widely recognized in the scientific world, whose name is given to laws, physical phenomena, and units physical quantities, founder of the doctrine of the electromagnetic field. Faraday was born in 1791 in London. His father and older brother were blacksmiths, his mother, the daughter of a farmer, was a wise and hardworking woman. The family lived poorly, so after graduating from primary school, Faraday was forced to work as a newspaper delivery boy, and at the age of 13 he became an apprentice in the bookshop of the bookbinder Ribot. Here he had the opportunity to supplement his meager knowledge through self-education; he was most interested in books on chemistry and physics. Already at this age, he developed a desire to rely only on facts and confirm messages by conducting own experiences. He tried to conduct physical and chemical experiments in the home laboratory he created.

Among the customers who visited the bookbinding workshop were those who belonged to the world of science. They helped the young man, devoted to his favorite sciences, get to the lectures of some scientists, which were intended for the public. One day he was lucky enough to attend lectures by the great physicist Humphry Davy, who invented a safety lamp for miners. Faraday wrote to the scientist and soon received an invitation from Davy to work as an assistant in the laboratory of the Royal Institution. In the fall of 1813, Davy takes Faraday with him on a long trip to European scientific centers, where Faraday met such world-famous scientists as M. Chevrel, A. Ampere and others, who also paid attention to a young assistant with brilliant abilities.
After returning to England in 1815, Faraday began scientific research at the Royal Institution. At first he helps Davy conduct chemical experiments, and later begins to conduct independent research. In 1816, he gave lectures on physics and chemistry at the Society for Self-Education; in 1818, he published his first work on physics. During the period before 1821, he published about 40 more works on chemistry. He was the first to obtain chlorine in liquid form.

The year 1821 was marked for Faraday by a number of significant events. So, in June 1821 he married Miss Bernard, this marriage was long and happy. In the same year, he took the place of overseer of the building, as well as the laboratories of the Royal Institution, and published a scientific work on the rotation of a current-carrying conductor around a magnet and a magnet around a current-carrying conductor. In 1823, he made a discovery in the field of physics - he established a method for converting gases into liquids. In 1824, Faraday was elected a member of the Royal Society, a year later he became director of the laboratory of the Royal Institution, and in 1827 he received a professorship here. For 10 years, Faraday explored the connection between electrical and magnetic phenomena, and in 1831 he made the discovery of electromagnetic induction, which brought him fame. In 1833-34, while studying the passage of current through solutions of acids, salts and alkalis, Faraday discovered the laws of electrolysis, called “Faraday’s laws”. In 1845, he discovered the phenomenon of rotation of the plane of polarization in a magnetic field and diamagnetism.