Lebedev Petr Nikolaevich. Petr Nikolaevich Lebedev

There was a professor at Moscow University, physicist Pyotr Nikolaevich Lebedev (1866-1912). Like Stoletov, Lebedev fought for a materialistic worldview. He was the mentor of many physicists. Among Lebedev's students were such prominent figures of Soviet science as academicians and P.P. Lazarev.

P. N. Lebedev saw science as a weapon in the struggle for the good of the people.

The scientist inevitably came into open conflict with the tsarist government.

In 1911, when the autocracy announced a new campaign against universities, Lebedev, along with a group of leading scientists, left the university in protest. The famous scientist was invited to work in Stockholm, at the Nobel Institute, but, despite the most flattering conditions that were offered to him, the scientist did not leave his homeland. Having created a small laboratory in the basement of one of the Moscow houses with private funds, the physicist and a group of young people continued their research.

But Lebedev’s health, undermined by all the adversities, deteriorated sharply, and in March 1912 the scientist died. He was only 46 years old.

Lebedev's discovery of light pressure brought him worldwide fame. He set this task for himself in his youth.

“I love this issue with which I have been busy for a long time with all my soul, just as I imagine parents love their children,” twenty-five-year-old Pyotr Nikolaevich Lebedev wrote to his mother in 1891.

The question that fascinated the young scientist was one of the most difficult in physics.

From the electromagnetic theory of light it followed that rays not only illuminate an object, but also put pressure on it. However, no one has yet been able to experimentally detect light pressure. How tempting it was to prove the existence of this pressure! After all, this would serve as another argument in favor of the truth of the electromagnetic theory of light, a theory that asserted that both light and the waves generated by an electric vibrator - radio waves, as we now call them - are closest relatives.

All these are electromagnetic waves, differing only in their lengths, the theory said.

And how important it was for astronomers to verify the existence of light pressure! Perhaps sunlight is the “wind” that deflects comet tails...

The failures of his predecessors did not frighten Lebedev. He set out to prove irrefutably, experimentally, the existence of light wind.

For deciding your main task Lebedev did not get started right away. At first, he investigated the nature of waves, more powerful and larger - waves on water, sound waves, waves generated by electric vibrators. Through brilliant experiments, Lebedev established the effect of waves on the obstacles they encountered. Your work " Experimental study ponderomotive action of waves on resonators", in which he combined studies of waves of various physical nature, Lebedev submitted to Moscow University for a master's degree. The academic council of the university highly appreciated this work: P. N. Lebedev was immediately awarded a doctorate.

While studying electromagnetic waves, the scientist managed to obtain very short radio waves. Mirrors made by Lebedev to study and reflect these waves and prisms made of sulfur and resin to refract them could be hidden in vest pocket- they were so miniature. Before Lebedev, experimenters had to use prisms weighing several pounds.

Miniature “light mills” designed by P. N. Lebedev.

Scheme of P. N. Lebedev’s experiment to determine light pressure on solids. The light of the electric arc located at point B, through a system of lenses and mirrors, falls on the wings of a miniature “mill” suspended in a vessel R from which air has been pumped out.

Diagram of the installation with which Lebedev discovered the pressure of light on gases.

Lebedev's research, remarkable for the subtlety of his experiments, had worldwide significance. But this was only the beginning of the work. The most difficult thing awaited the scientist ahead.

The forces of light pressure are unimaginably small. Suffice it to say that the bright rays of the sun hitting a palm placed in their path put pressure on it a thousand times less than a mosquito landing right there.

The difficulties did not stop there. Under normal conditions, light pressure is drowned out by stronger extraneous influences. Light heats the air, creating upward currents in it. Light also heats the object itself - air molecules hitting a heated surface bounce off it at a higher speed than molecules hitting the unlit side. The action of upward flows and recoil of molecules far exceeds the pressure of light on an object.

To measure light pressure, Lebedev designed tiny pinwheels, which are thin metal wings suspended on a very thin thread. The light falling on the wings was supposed to turn them. To protect his device from extraneous influences, Lebedev placed it in a glass vessel, from which he carefully pumped out the air.

Having developed an ingenious experimental technique, Lebedev completely eliminated the influence of air flows and molecular recoil. Light pressure, not yet captured by anyone, in its pure form, visibly appeared before the wizard of the physical experiment.

Lebedev's report created a sensation at the World Congress of Physicists in 1900. William Thomson, who was present at the congress, approached K. A. Timiryazev after Lebedev’s report. “Your Lebedev made me surrender to his experiments,” said Kelvin, who spent his entire life fighting against the electromagnetic theory of light, which claimed, in particular, that there is light pressure.

Having proved that light presses on solids, Lebedev began to study an even more difficult problem. He decided to prove that light also puts pressure on gases.

Rays of light passing through the gas chamber designed by Lebedev caused it to move. They created, as it were, a draft that carried away gas molecules. The flow of gas was deflected by a thin piston embedded in the chamber. In 1910, Lebedev rightfully told the scientific world: “The existence of pressure on gases has been established experimentally.”

The significance of Lebedev’s work was not limited to the fact that they helped to establish the electromagnetic theory of light and gave the key to many astronomical phenomena. Lebedev proved through his experiments that light manifests itself as something material, weighty, and having mass.

From the data found by Lebedev it followed that the pressure of light and, therefore, the mass of light, the greater the brighter the light, the greater the energy it carries. An amazing connection has been established between energy and mass of light. The discovery of the Russian physicist went far beyond the theory of light.

Modern physics has extended the principle of the connection between mass and energy to all types of energy. This principle has now become a powerful tool in the struggle to master the energy of the atomic nucleus, the basis for calculations of atomic energy processes.

Pyotr Nikolaevich Lebedev was born in 1866 into a merchant family. Higher education received at the Moscow Higher Technical School, where he perfectly studied turning and metalworking crafts and learned to design complex instruments, which later greatly helped him in the design of experimental installations.

However, interest in physics prevailed, and in 1887, without graduating from the Technical School, Lebedev went to Germany, to the laboratory of a famous German physicist.

In 1891, Lebedev wrote a dissertation on dielectrics. At the same time, the scientist wonders about the reasons for the appearance of comet tails when comets approach the Sun. It was then that he came up with an idea that later brought him worldwide fame. Lebedev raises the question of the pressure of radiant energy and the possibility of its experimental proof.

In 1891, Lebedev, at the invitation of A.G. Stoletov returned to Moscow and became an assistant in the physics laboratory of Moscow University. In a cramped, poorly equipped room, he began work on studying the influence of electromagnetic, hydrodynamic and acoustic waves on resonators. For these works, in 1899 Lebedev was awarded (without defending a master's thesis) the degree of Doctor of Physical and Mathematical Sciences, and in 1900 he became a professor at Moscow University.

By this time, he had already gained fame and experience as one of the first researchers to rely on the theory of J. C. Maxwell. Developing the work of G. Hertz, who experimentally confirmed the existence of electromagnetic waves, Lebedev created an installation for generating and receiving electromagnetic radiation with wavelengths of 6 and 4 mm, studied reflection, refraction, polarization, interference of these waves and other phenomena. The results obtained by Lebedev were another strong confirmation of Maxwell's theory.

In 1900, Lebedev carried out his famous experiments in which, with the help of masterfully made, although rather modest instruments, he confirmed Maxwell's theoretical prediction about the pressure of light.

The famous physicist W. Thomson, better known as Lord Kelvin, after whom the absolute temperature scale is named, admitted: “I spent my whole life fighting with Maxwell, did not recognize his light pressure, and now... with his experiments Lebedev made me give up.”

Studying the pressure of light on gases prompted Lebedev to become interested in the origin of comet tails.

In 1900, Lebedev published the first report on the positive results of his experiments on the pressure of light on solids, in 1901 - the classic “Experimental Study of Light Pressure”. Only in 1910, after countless experiments, after he had built and studied more than 20 final instruments alone, Lebedev proved the pressure of light on gases (“Journal of the Russian Physico-Chemical Society”, 1910).

In 1911, Lebedev, like many other professors at Moscow University, left the university in protest against the actions of the Minister of Education limiting the rights of the university. A new physics laboratory was organized with private donations, where Lebedev and his students moved. Last years Lebedev worked a lot on the question of the movement of the earth in the ether, tried to find out the causes of terrestrial magnetism and expressed extremely bold original ideas about this question.

Lebedev suffered from heart disease and once, while still relatively young, experienced clinical death, but then they managed to bring him back to life. Lebedev died on March 14, 1912 from heart disease. He lived only 46 years.

Lebedev created a whole school of physicists. In 1905, about twenty young scientists worked in his laboratory, who were destined to play a prominent role in the development of physics in Russia.

Named after P. N. Lebedev Physics Institute Russian Academy Sciences in Moscow.

Stories about physics scientists. 2014

Lebedev Pyotr Nikolaevich Lebedev Pyotr Nikolaevich

(1866-1912), physicist, creator of the first Russian scientific school physicists. Professor at Moscow University (1900-11), resigned in protest against the oppression of students. First received (1895) and studied millimeter electromagnetic waves. Discovered and measured the pressure of light on solids (1899) and gases (1907), quantitatively confirming the electromagnetic theory of light. The Physics Institute of the Russian Academy of Sciences bears the name of Lebedev.

LEBEDEV Petr Nikolaevich

LEBEDEV Petr Nikolaevich (1866-1912), Russian physicist, creator of the first Russian scientific school of physicists. Professor at Moscow University (1900-11), resigned in protest against the harassment of students. First received (1895) and studied millimeter electromagnetic waves. Discovered and measured the pressure of light on solids (1900) and gases (1908), quantitatively confirming the electromagnetic theory of light. The Physics Institute of the Russian Academy of Sciences bears the name of Lebedev.
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LEBEDEV Petr Nikolaevich, Russian experimental physicist, who was the first to experimentally confirm the presence of light pressure, the creator of the first Russian school of physicists.
Years of study
Lebedev was born into a merchant family. I became interested in physics back in teenage years, but since access to the university was closed for him, as a graduate of a real school, he entered the Moscow Higher technical school. Subsequently, Lebedev said that familiarity with technology turned out to be very useful to him in the design of experimental installations.
In 1887, without graduating from the Technical School, Lebedev went to Germany, to the laboratory of the famous German physicist A. Kundt (cm. KUNDT August Adolf Eduard Eberhard), for whom he worked first in Strasbourg (1887-88), and then in Berlin (1889-90). In 1891, having written a dissertation “On the measurement of dielectric constant vapors and on the Mossoti-Clausius theory of dielectrics,” he passed the exam for the first academic degree.
Return to Russia
Upon his return to Russia in 1891, Lebedev received a position at Moscow University as an assistant in the laboratory of Professor A. G. Stoletov (cm. STOLETOV Alexander Grigorievich). The series of works carried out by Kundt was included in Lebedev’s master’s thesis “On the ponderomotive action of waves on resonators” presented in 1899, which was so highly appreciated that Lebedev was immediately awarded the degree of Doctor of Physics. In 1900 he was approved as a professor at Moscow University, where he organized a laboratory. Not without some opposition from some colleagues, Lebedev began to actively conduct experimental work. By this time, he had already gained fame and experience as one of the first researchers to rely on the theory of J. C. Maxwell (cm. MAXWELL James Clerk). Back in 1895, Lebedev created the finest installation for generating and receiving electromagnetic radiation with wavelengths of 6 and 4 mm, and studied reflection, refraction, polarization, interference of these waves and other phenomena.
Light pressure
In 1900, Lebedev, with the help of masterly experiments, although performed with modest means, confirmed Maxwell’s theoretical prediction about the pressure of light on solids, and in 1908 - on gases. It appeared important milestone in the science of electromagnetic phenomena. Famous English physicist W. Thomson (cm. THOMSON William) belong to the words: “All my life I fought with Maxwell, did not recognize his light pressure, and now... Lebedev forced me to surrender to his experiments.”
Lebedev also studied the effect of electromagnetic waves on resonators and, in connection with these studies, put forward deep considerations regarding intermolecular interactions, and studied issues of acoustics, in particular hydroacoustics. Studying the pressure of light on gases prompted Lebedev to become interested in the origin of comet tails.
The first scientific physics school in Russia
Not limiting himself to research activities, Lebedev devoted a lot of effort to creating a scientific physics school, which, in essence, was the first in Russia. By 1905, his laboratory already included about twenty young scientists who were destined to play a prominent role in the development of physics in Russia. Lebedev’s assistant and closest assistant was P. P. Lazarev (cm. LAZAREV Petr Petrovich), who after the death of his teacher became the head of the laboratory, and in 1916 - the director of the first Research Institute of Physics in Moscow, from which S. I. Vavilov came (cm. VAVILOV Sergei Ivanovich), G. A. Gamburtsev (cm. GAMBURTSEV Grigory Alexandrovich), A. L. Mints (cm. MINTs Alexander Lvovich), P. A. Rebinder (cm. REBINDER Petr Alexandrovich), V.V. Shuleikin (cm. SHULEYKIN Vasily Vladimirovich), E. V. Shpolsky (cm. SHPOLSKY Eduard Vladimirovich) and others. The Physical Institute of the Russian Academy of Sciences in Moscow is named after P. N. Lebedev.
Latest experiments
Lebedev's experiments required the use of carefully thought-out, sometimes quite complex, “mechanics”. This sometimes gave rise to absurd reproaches that Lebedev “reduced science to the level of technology.” However, Lebedev himself considered the issue of the connection between science and technology to be very important.
Lebedev's last cycle of research is still underestimated. These studies were aimed at testing the hypothesis of the English physicist Sutherland regarding the redistribution of charges in conductors under the influence of gravity. In celestial bodies, planets and stars, according to Sutherland, electrons are “squeezed out” from the internal regions (where the pressure is high) to the surface, due to which the internal regions are charged positively, and the surface of the bodies is negatively charged. The rotation of bodies together with the charges redistributed in them should generate magnetic fields. Thus, a physical explanation was proposed for the origin of the magnetic fields of the Sun, Earth and other celestial bodies.
Sutherland's hypothesis did not have a reliable theoretical basis at that time, and therefore the experiment planned by Lebedev to test it acquired particular importance. Realizing that centrifugal forces, like gravitational ones, should cause a redistribution of charges, Lebedev put forward a simple but very ingenious idea: if Sutherland’s hypothesis is correct, then a magnetic field should arise with the rapid rotation of electrically neutral bodies. It is precisely this “magnetization by rotation” that experiment was supposed to reveal.
The work took place in very difficult conditions. In 1911, in protest against the reactionary actions of the Minister of Public Education L. A. Kasso (cm. CASSO Lev Aristideovich) Lebedev, together with other progressive teachers, decides to leave Moscow University. As a result, a very subtle experiment that he conducted in the basement Faculty of Physics, was crumpled. The desired effect could not be found. The reason for the failure was not the lack of effect, but the insufficient sensitivity of the installation: the estimates for magnetic fields that Lebedev was guided by and which were based on the work of Sutherland turned out to be significantly overestimated. At Shanyavsky University, using private funds, Lebedev created a new physics laboratory, but did not have time to continue his research. Lebedev suffered from heart disease and once, while still relatively young, experienced clinical death: his heart suddenly stopped while he was rowing a boat, but then they managed to bring him back to life. He lived only 48 years.

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Pyotr Nikolaevich Lebedev (1866-1912)

Pyotr Nikolaevich Lebedev went down in the history of world science as a most skillful experimental physicist who first discovered and measured the pressure of light. P. N. Lebedev, along with M. V. Lomonosov, is one of the remarkable figures in the history of Russian physics. He was the first organizer of a collective scientific work in the field of physics and large research laboratories that have become models for scientific institutes Nowadays.

Pyotr Nikolaevich Lebedev was born on March 8, 1866 in Moscow, into a cultured merchant family. After studying at a real school, P. N. Lebedev entered the Moscow Technical School. However, he was attracted to difficult fundamental questions that went far beyond the program of the courses he studied. The archives of the USSR Academy of Sciences contain large notebooks of the young man Lebedev, revealing his extraordinary inventive wit, knowledge, and at the same time special seriousness and concentration. Without graduating from the Technical School, P. N. Lebedev went abroad in 1887, to the University of Strasbourg, to study physics.

Here he worked for the famous experimental physicist August Kundt. Subsequently, P. N. Lebedev wrote a wonderful obituary in memory of Kundt, containing his detailed and touching description. “Possessing a remarkable physical instinct,” writes Lebedev, “physikalische Nase, as he himself called his talent, Kundt guessed the connection between individual, heterogeneous phenomena, and also with amazing clarity grasped the essence of a mathematically developed theory and was always able to pose the question point-blank. being the most daring consequence of the theory, it would be accessible to direct experimental research." This characteristic of Kundt can be fully applied to P. N. Lebedev himself.

Kundt did not remain in Strasbourg for long. In 1888, he received a department in Berlin, and P. N. Lebedev followed him. Here, in addition to studying with Kundt, P. N. Lebedev listened to theoretical lectures by Helmholtz.

While studying in a real school as a child, P. N. Lebedev did not study Latin language. Therefore, he was unable to pass the doctoral test in Berlin, where knowledge of ancient languages ​​was necessary. I had to return to Strasbourg - Latin was not required there. In Strasbourg, P. N. Lebedev quickly completed his experimental dissertation work, passed the exams and received the degree of Doctor of Philosophy. P. N. Lebedev's dissertation was entitled "On the measurement of dielectric constant vapors and the Mossotti-Clausius theory of dielectrics." This excellent work, presented in 1891, was at one time done to test the consequences of the phenomenological theory of dielectrics, but it has retained its interest now in connection with the more specific structural-molecular concepts of our time.

From the surviving letters of P. N. Lebedev dating back to this period of his life, it is clear that he wrote a lot then and thought about even more, in addition to his doctoral work. His studies on the theory of comet tails date back to 1890. These studies became the beginning of the main work of his life - research on light pressure.

Seneca also knew that comet tails deviate from the Sun. Kepler, Newton and others suggested that the mechanical pressure of light could be the cause of this deviation. In the 18th century they tried to discover it experimentally and, indeed, found it. In fact, it turned out, however, that the observed phenomena are caused by secondary thermal processes and have nothing to do with light pressure.

There were too many reasons competing with light pressure in any experiment; on the other hand, there was no idea about the theoretical value of the possible light pressure. IN late XVIII V. the physicist and astronomer Haratsaker pointed out, for example, that, according to travelers, the sun's rays, with their pressure, slow down the movement of the Danube. For the first time, Maxwell, on the basis of his electromagnetic theory of light, calculated the theoretical value of light pressure, equal, for the case of light falling on a completely absorbing surface, to the quotient of dividing the light energy arriving per second by the speed of light. For sunlight falling on earth's surface, this pressure is approximately equal to five hundred millionths of a gram per square centimeter. Later it turned out that any wave theory of light leads to the same value for light pressure as Maxwell’s theory, while the corpuscular concept gives a value twice as large. Thus, the problem of light pressure dates back at least three centuries; it was studied by such physicists and astronomers as Kepler, Newton, Euler, Fresnel, Maxwell, Boltzmann. It was of fundamental importance for science and yet until the end of the 19th century. remained unresolved.

P. N. Lebedev took on this most difficult task. In 1891, his note “On the repulsive force of ray-emitting bodies” appeared. In it, based on known data on solar radiation, P. N. Lebedev proves that in the case of very small particles the repulsive force of light pressure must exceed Newtonian attraction, and thus the deflection of cometary tails can indeed be explained by light pressure. At the end of his note, P. N. Lebedev notes that his calculations are not quantitatively applicable to molecules, but do not lose their validity qualitatively.

P. N. Lebedev was right when, excited by his thoughts, he wrote in a private letter: “I seem to have made a very important discovery in the theory of the movement of luminaries, especially comets.” In modern astrophysics, the enormous role of light pressure as a cosmic factor, along with Newtonian attraction, becomes obvious. The first physically substantiated indication of this was made by P. N. Lebedev.

Having set himself the task of clarifying the question of the mechanical forces arising between the emitting and absorbing molecules, P. N. Lebedev returned, full of plans, to Moscow in 1891.

He gets a position as an assistant at Moscow University at the department of Professor A.G. Stoletov and, in very difficult conditions, sets up his laboratory, remaining cheerful and full of creative energy.

Three years later, in 1894, the first part of it appeared great job, which later served as a doctoral dissertation “Experimental study of the ponderomotive effect of waves on resonators.” Due to the exceptional quality of his work, P. N. Lebedev was awarded a doctorate without first defending a master's thesis and corresponding exams - a very rare case in university practice. The first part of this work is devoted to the experimental study of the interactions of electromagnetic resonators, the second - to hydrodynamic resonators (oscillating balls in a liquid), the third - to acoustic ones. Experimentally (in accordance with theory), the identity of these different cases was discovered. From the experimental side, the work was an example of P. N. Lebedev’s thoroughness, wit and, so to speak, jewelry skill. “The main interest of studying the ponderomotive action of wave-like motion,” the author wrote, “lies in the fundamental possibility of extending the found laws to the region of light and thermal emission of individual molecules of bodies and pre-calculating the resulting intermolecular forces and their magnitude.”

The work was completed in 1897. Wave pressure was studied using models. This was the second stage of the main case of P. N. Lebedev. The third, most important stage lay ahead - an attempt to overcome the difficulties encountered over the centuries by many unsuccessful predecessors of P. N. Lebedev, and to discover and measure the pressure of light in the laboratory.

In 1900, this stage also ended with complete success. The light pressure was found. P. N. Lebedev managed to isolate the interfering, so-called radiometric, forces and convection currents from it and measure it. In appearance, P. N. Lebedev’s device was simple. The light from the voltaic arc fell on a light wing suspended on a thin thread in a glass balloon from which air had been pumped out, and the light pressure could be judged by the twisting of the thread. In reality, behind this simplicity were hidden countless difficulties overcome. The wing actually consisted of two pairs of thin platinum circles. One of the circles of each pair was shiny on both sides, the other two had one side covered with platinum niello. Moreover, both pairs of circles differed in thickness. In order to eliminate the convection (movement) of gas that occurs when the temperatures of the wing and the glass balloon differ (the temperature difference arises when light is absorbed by the wing), the light is directed first to one side or the other of the wing. Since in both cases the convection is the same, the difference in the resulting deviations does not depend on the convection. The radiometric forces were first of all weakened as far as possible (by increasing the volume of the balloon and decreasing the pressure). In addition, the radiometric effect could be taken into account by comparing the result when light falls on a thick and thin blackened circle. P. N. Lebedev could rightfully and proudly finish his message in a short phrase: “Thus, the existence of Maxwellian-Bartholi pressure forces has been experimentally established for light rays.”

The experiments of P. N. Lebedev brought him worldwide fame and forever inscribed his name in the history of experimental physics. In Russia, he received a prize from the Academy of Sciences for these experiments and was then elected to a corresponding member of the Academy. The impression that P. N. Lebedev’s experiments made on the scientific world is evidenced, for example, by the words of the famous English physicist Lord Kelvin, said to the famous Russian scientist K. A. Timiryazev: “You, perhaps, know that I have fought all my life with Maxwell, not recognizing his light pressure, and now your Lebedev made me surrender to his experiments."

However, P. N. Lebedev did not consider the task completed. For cosmic phenomena, the main importance is not the pressure on solid bodies, but the pressure on rarefied gases consisting of isolated molecules. Meanwhile, in the first decade of our century, there were still many uncertainties regarding the structure of molecules and their optical properties. It was unclear how one could move from pressure on individual molecules to pressure on the body as a whole. The theoretical state of the matter at that time, in short, was such that experimental intervention was required.

The experimental task facing P.N. Lebedev was this time even more difficult than the previous one, and attempts to solve it lasted ten years. But this time too, the experimental art of P. N. Lebedev overcame all difficulties. In P. N. Lebedev’s miniature device, gas under the pressure of absorbed light received a rotational motion, transmitted to a small piston, the deflection of which could be measured by the displacement of the mirror “bunny”. The most important difficulty of the experiment - eliminating the inevitable convection of gas in the device - was overcome by P. N. Lebedev with the ingenious technique of mixing hydrogen into the gas under study. Unlike other gases, hydrogen is a good conductor of heat, quickly equalizing temperature inhomogeneities in the vessel. This technique was decisive. P. N. Lebedev’s new experiments, published in 1910, were greeted with delight by the world physics community. The British Royal Institution chose P. N. Lebedev as its honorary member. The brilliant experimental physicist V. Vin wrote in a letter to the Russian physicist V. A. Mikhelson that P. N. Lebedev mastered “the art of experimentation to an extent like hardly anyone else in our time.”

This ended the amazing series of works by P. N. Lebedev on light pressure. It was interrupted by his premature death. The solution to the question of light pressure, however, has not yet been completed. Remained experimentally unexamined special cases pressure of elliptically polarized light, and most importantly, it has not yet been possible to experimentally detect the nature of light pressure on an individual particle of matter. This was done much later by A. Compton, who observed the elementary effect of light pressure and scattering of X-rays and gamma rays by electrons in a cloud chamber. Elementary light pressure turned out to be quantum, having a discontinuous nature. Light pressure, measured by P. N. Lebedev, was the average statistical value of pressures in a variety of elementary processes. P. N. Lebedev did not have to take part in revealing the statistical nature of the phenomenon, to the masterful study of which he devoted his life.

The number of other works by P. N. Lebedev is small. But each of them is important and has retained its significance even now. In the first years in Moscow, he again carried out a study “On the double refraction of rays of electric force”, astonishing in its skill of experiment, experimenting with electromagnetic waves 6 millimeters long, a miniature “Nicol” and a “quarter-wave plate” of crystalline sulfur. In 1902 he published a short but very important physical measurements and technology article “Thermoelements in a vacuum as a device for measuring radiant energy.” The principle of a thermoelement in a vacuum, put forward by P. N. Lebedev, is currently widespread, in particular in military equipment. In connection with one of the hypotheses about the nature of terrestrial magnetism, P. N. Lebedev modified Hilbert’s experiment, which aimed to attempt to excite an electric current in a conductor as it moved through the ether. Based on the assumption of the movement of the Earth in a stationary ether, P. N. Lebedev decided to take advantage of this movement; He carried out the experiment, as usual, with the utmost care, but received a negative result. True, this experiment did not so much refute the Rowland-Hilbert hypothesis as the assumption of a stationary ether.

The last, dying, experimental work of P. N. Lebedev also concerned the nature of terrestrial magnetism. He wanted to experiment with a rotating model of the Earth to test Sutherland's hypothesis, in which the magnetic effect of the rotating Earth was explained by the displacement of unlike charges in a neutral atom. This difficult experience also produced a negative result.

While working at Moscow University, P. N. Lebedev paid main attention to the research work of his students and employees. True, he, like other professors, gave lectures, even published short summary these lectures, but essentially had little interest in teaching. His first lecture to beginning students always contained mainly an appeal to them to become researchers without fear of difficulties. For the first time in Russia, he dared to organize a physics laboratory with a relatively very a large number working persons. In 1901, only three people worked for him, in 1910 the number of workers reached 28. If we take into account that all the topics of work were given and carefully thought out (down to the drawings of instruments) by P. N. Lebedev himself, that there were no laboratory assistants , the mechanics and glassblowers were the workers themselves, that the laboratory's funds and equipment were extremely limited, that it was located in a poorly comfortable basement, then the enormous stress and energy required from P. N. Lebedev to manage this laboratory will become clear. Meanwhile, year after year, more and more often a number of good and excellent work, on many of which one could feel the masterful hand of the teacher. P. N. Lebedev became the pioneer of a remarkable and completely new business for Russia - a large collective research work. Subsequently, in 1911, in a newspaper article " Russian society and Russian national laboratories”, published in “Russian Vedomosti”, P. N. Lebedev outlined in some detail his point of view and arguments about the benefits and necessity of creating large research laboratories. This was the first declaration of a system of organizing science, which was fully realized only in USSR.

In 1911, during the era of the maximum flourishing of P. N. Lebedev’s activity and glory at Moscow University, as a result of the reactionary actions of the tsarist government, and especially the then Ministry of Public Education, the most talented and liberal part of the professors had to leave the university and seek shelter for themselves in others educational institutions or simply rely on the help of private individuals. In protest against the actions of the Minister of Education L. Casso, P. N. Lebedev also resigned, and along with him his employees who worked in his laboratory left the university. A huge business was destroyed. P. N. Lebedev immediately received invitations from foreign scientific institutions. In particular, the director of the physicochemical laboratory of the Nobel Institute in Stockholm, prof. Arrhenius wrote to him: “Naturally, it would be a great honor for the Nobel Institute if you wished to settle and work there, and we, without a doubt, would provide you with all the necessary funds so that you have the opportunity to continue working... You, of course , would receive a completely free position, as it corresponds to your rank in science." But P. N. Lebedev refused all these proposals. He remained in his homeland and, in extremely difficult conditions, using private funds and public assistance, he organized a new physics laboratory. A basement was rented in Dead Lane (house no. 20) in Moscow, where in 1911 his laboratory was located in several rooms. Here he completed his last experimental work on the magnetometric study of rotating bodies. Private donors raised funds for the construction of a new physics institute for P. N. Lebedev according to a plan drawn up by himself. This institute, however, was completed only in 1916, four years after Lebedev’s death. This building currently belongs to the USSR Academy of Sciences; it houses the P. N. Lebedev Physics Institute for experimental work on the magnetometric study of rotating bodies. Private donors raised funds for the construction of a new physics institute for P. N. Lebedev according to a plan drawn up by himself. This institute, however, was completed only in 1916, four years after Lebedev’s death. This building currently belongs to the USSR Academy of Sciences; it houses the P. N. Lebedev Physics Institute.

On March 14, 1912, P. N. Lebedev passed away. He died at the age of 46 and was buried at the Alekseevsky cemetery. In 1935, due to the liquidation of the cemetery, the ashes of P. N. Lebedev were transferred to the cemetery of the Novodevichy Convent.

Everyone responded to the death of P. N. Lebedev scientific world. Many telegrams and letters were sent from prominent scientists, among whom were Roentgen, Nernst, Arrhenius, Thomson, Warburg, Rubens, Crookes, Curie, Righi and others.

In the person of P. N. Lebedev, Russia lost not only a great scientist, but also a wonderful organizer of science, whose thoughts and undertakings could only be fully realized in Soviet Russia.

The main works of P. N. Lebedev: Collected Works, ed. Phys. society named after P. N. Lebedeva, M., 1913 [I. Science articles: On the measurement of dielectric constants of vapors and the Mossotti-Clausius theory of dielectrics (Strasbourg thesis), 1891; On the repulsive force of ray-emitting bodies, 1891; On the double refraction of rays of electric force, 1895; Experimental study of the ponderomotive action of waves on resonators (doctoral dissertation), 1894-1897; Experimental study of light pressure, 1901; Thermoelements in a vacuum as a device for measuring radiant energy, 1902; Experimental study of light on gases, 1910; Magnetometric study of rotating bodies, 1911, etc. II. Popular articles and speeches: On the motion of stars according to spectroscopic studies, 1892; August Kundt, 1894; About x-rays discovered by X-rays, 1896; Experimental work of A. G. Stoletov, 1898; Methods of obtaining high temperatures, 1899; Rock of Electromagnetic Waves in the Ether, 1901; Advances in acoustics over the past 10 years; 1905; Russian Society and Russian National Laboratories, 1911; In memory of the first Russian scientist (M. V. Lomonosov), 1911; Pressure of light, 1912, etc.].

About P. N. Lebedev:Lazarev P. P., P. N. Lebedev ( biographical sketch) in "Collected Op." P. N. Lebedeva, M., 1913; His, P. N. Lebedev and Russian physics, "Vremennik of the Society for Promoting the Success of Experimental Sciences named after Kh. S. Ledentsov", v. 2; Charnovsky N. F., Characteristic features of the activities of P. N. Lebedev in the Council of the Society named after. Kh. S. Ledentsova, ibid.; Lazarev P. P., Lebedev Laboratory at Shanyavsky University, in the same place, 1913, c. 1; Kravets T. P., P. N. Lebedev and the physical school he created, “Nature”, 1913, No. 3 (there is a separate reprint); 3ernov V.D., Pyotr Nikolaevich Lebedev, "Scientific Notes of Moscow University", c. LII, Physics, M., 1940; Kaptsov N. A., School of Pyotr Nikolaevich Lebedev, in the same place.

February 24, 1866 - March 01, 1912

outstanding Russian experimental physicist, the first to experimentally confirm Maxwell's conclusion about the presence of light pressure, founder of Russia's first scientific physics school, professor at Moscow University

Founder of Russia's first scientific physics school, professor at Moscow University (1900-1911). He was dismissed as a result of the actions of the Minister of Education, known as the “Casso affair”.

Biography

Born in Moscow on March 8, 1866. In his youth, he became interested in physics, but access to the university was closed for him, a graduate of a real school, so he entered the Imperial Moscow Technical School. Subsequently, P. N. Lebedev said that familiarity with technology turned out to be very useful to him in the design of experimental installations.

Education

In 1887, without graduating from IMTU, Lebedev went to Germany, to the laboratory of the famous physicist August Kundt, for whom he worked first in Strasbourg and then in Berlin. In 1891, he wrote a dissertation “On the measurement of dielectric constant vapors and the Mossotti-Clausius theory of dielectrics” and passed the exam for the first academic degree. Upon returning to Russia in 1892, he received a position at Moscow University as an assistant in the laboratory of Professor A. G. Stoletov.

The series of works carried out by Kundt was included in Lebedev’s master’s thesis “On the ponderomotive action of waves on resonators” presented in 1900, for which he was immediately (an exceptional case!) awarded the degree of Doctor of Physics. Soon he was approved as a professor at Moscow University.

Scientific activity

Not without some opposition from some of his colleagues, Lebedev began to actively conduct experimental work. By that time, he had already gained fame and experience as one of the first researchers to rely on Maxwell's theory. Back in 1895, he created an installation for generating and receiving electromagnetic radiation with wavelengths of 6 mm and 4 mm, and studied reflection, refraction, polarization, interference, etc.

In 1899, P. N. Lebedev, with the help of masterly experiments, although performed with modest means, confirmed Maxwell’s theoretical prediction about the pressure of light on solids, and in 1907 - on gases (the discovery of the effect of light pressure). This research was an important milestone in the science of electromagnetic phenomena. One of the prominent physicists of that time, William Thomson, said: “All my life I fought with Maxwell, not recognizing his light pressure, and now< … >Lebedev made me surrender to his experiments.”

P. N. Lebedev also dealt with issues of the action of electromagnetic waves on resonators and, in connection with these studies, put forward deep considerations regarding intermolecular interactions, and paid attention to issues of acoustics, in particular hydroacoustics.

Studying the pressure of light on gases prompted Lebedev to become interested in the origin of comet tails.

Not limiting himself to research activities, P. N. Lebedev devotes a lot of effort to creating a scientific school, which was essentially the first in Russia and the emergence of which continues to be felt to this day. By 1905, about twenty of his young students were already working in the laboratory, who were later destined to play a prominent role in the development of physics in Russia. Of these, it is appropriate to name first of all