Nobel laureates: Max Planck. The most constant of physicists
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Once, a neat young man entered the office of Philipp von Jolly, a professor at the University of Munich, timidly knocking, - Princess Dzintara began to tell another evening fairy tale to her children.
I recently entered your university,” he said, “and I want to study theoretical physics.
Theoretical physics? - the professor was surprised. - I do not advise. In this science, all the discoveries have already been made, it remains to clean up a couple of holes.
The professor is understandable. It was 1874. By this time, theoretical physics had practically reached perfection, being firmly based on Newton's mechanics, thermodynamics, and also on Maxwell's electrodynamics.
The young man answered modestly:
I am not going to make discoveries, I would just like to understand what has already been achieved in the field of theory.
Well, I will not dissuade you, you can attend my lectures. What is your name?
Max Plank.
A young man named Max Karl Ernst Ludwig Planck was from an old noble family who provided Germany with military men, lawyers and scientists. He was born in the city of Kiel in the family of civil law professor Johann Julius Wilhelm von Planck and Emma Planck. As a child, he studied piano and organ and made great strides. In 1867 the family moved to Munich, where Max entered the Royal Maximilian Gymnasium. There the young man became interested in the exact and natural sciences. From 1874, Planck studied physics and mathematics for three years at the University of Munich and for another year at Berlin.
After graduation, he did not have a permanent job, but he diligently studied theoretical physics, studied the articles of Hermann Helmholtz, Gustav Kirchhoff and other prominent physicists. He was fascinated by thermodynamics for a long time (this area of physics studies the phenomena of heat and the transformation of various types of energy into each other). In 1879, Planck defended his dissertation at the University of Munich on the second law of thermodynamics. After that, the young talented physicist began to quickly move up the career ladder and by the age of 34 he became a professor of theoretical physics at the University of Berlin and director of the Institute for Theoretical Physics.
One day, a well-known electrical company turned to Professor Planck with a proposal to conduct research and find out how to achieve the maximum luminosity of a light bulb with minimal energy consumption? Planck responded and began work that opened a new era in science.
What is the merit of Planck? It has long been known that the intensity of its glow, as well as the color of the radiation, depends on the temperature of a body (for example, a hot wire in an electric lamp).
Right! cried Galatea. - The candle burns yellow, and the flame of electric welding is blue!
For the mass production of electric lamps, it is important to know exactly under what conditions their light will be as bright as possible. Professor Planck set himself the task of determining the spectrum of the glow of hot bodies and finding out how this spectrum depends on temperature. By this time, two laws were derived that determine the glow of bodies as a function of wavelength. One of them - Wien's law - described well the brightness of the glow in the short-wave region, but did not correspond to the experimental data in the long-wavelength part of the spectrum. The other - the Rayleigh-Jeans law - on the contrary, perfectly coincided with the experiment for long waves, but in the region of short waves it hopelessly lied: according to it, the main radiation energy is contained in the shortest waves.
Getting down to business, Planck decided to derive a formula that would fit well with the observed dependence of the glow on the wavelength, without worrying about its theoretical justification. As a theoretical physicist, he took the path of obtaining an empirical formula, because the glow of lamps was a practically important issue and manufacturers needed a working formula, but they did not think about theories.
Planck succeeded in deriving a mathematical law that gave correct data for radiation in both long and short waves, which coincided with experiment. It remains to be seen whether this formula is just a mathematical trick with no deep justification, or it can be obtained on the basis of existing scientific principles.
In search of a scientific justification for the proposed law, Planck relied on the work of the Austrian physicist Ludwig Boltzmann, who, deeper than his contemporaries, understood the statistical nature of thermodynamic relationships and founded statistical mechanics. After much effort, Planck found out that his formula did not proceed from known principles. But it can be perfectly derived if we assume that an elementary oscillator (a charge that oscillates) can emit waves only in portions proportional to the frequency of the wave. Planck wrote the energy of such a portion in the form
where h- a constant, which later became known in his honor as the Planck constant; ν - wave frequency.
It was a very strange expression that did not follow from the usual laws of physics.
What is his weirdness? - Andrey asked.
I'll try to explain. Hertz discovered that a circuit in which a stream of electrons moves back and forth emits radio waves. If we simplify the Hertz circuit to the limit, then we get an elementary oscillator - just an electric charge oscillating under the influence of some external force. A good example of such an oscillator is an electrically charged and swinging clock pendulum. Swinging or oscillating charged bodies or particles always emit electromagnetic waves. Maxwell's theory did not impose any restrictions on such radiation, and the condition that Planck was forced to base his formula on was that the oscillator cannot emit waves as it pleases: it must release energy only in separate portions (quanta). Whatever oscillators were considered, this condition did not change, they emitted energy as if by order in this way and not otherwise.
Planck published his theory in 1900, but neither he nor other scientists were in a hurry to admit the existence of the quantum theory he put forward. It was only through the efforts of Einstein and other physicists that the theory of light quanta began to gradually win its place in physical science.
Everything changed dramatically in 1913, when a young Dane named Niels Bohr came to the English city of Manchester to work in the laboratory of the outstanding British physicist Ernest Rutherford. Bohr proved that quanta are the foundation of the structure of matter, and thus opened a new page in the history of science. And Max Planck discovered something that completely changed the building of world theoretical physics, which was so beautiful and seemed almost complete.
In 1918, Planck received the Nobel Prize for his work. Dozens of scientific institutions in Germany, which were engaged in fundamental science, united in the Max Planck Society. The country's highest award for achievements in the field of theoretical physics was the Max Planck medal. Well, the most impressive evidence of Planck's contribution to world science was that among the five world fundamental constants: the speed of light, the charge and mass of the electron, the gravitational constant and Planck's constant, only one bears the name of its discoverer.
Mom, - Galatea asked carefully, - is there any other unknown world constant?
Dzintara smiled:
I think it has. But the discoverer is the first to know about the existence of such a constant.
Empirical formulas are not derived from any theory. They are selected or constructed from mathematical functions in such a way as to best describe the experimental data.
The full name of the German scientist is Max Karl Ernst Ludwig Planck. For many years he was one of the leaders of the German scientific community. He is credited with the discovery of the quantum hypothesis. The physicist studied thermodynamics, the theory of quanta and thermal radiation. The works of the scientist make him the founder of quantum physics. One of the few who dared to speak out in defense of the Jews during the period of Nazism in Germany. Until the end of his days, he remained faithful to science and practiced it as long as his health allowed.
Childhood and youth
Max Planck was born on April 23, 1858 in Kiel. His ancestors were from an old noble family. His grandfather (Heinrich Ludwig Planck) and great-grandfather (Gottlieb Jakob Planck) taught theology at the University of Göttingen.
Embed from Getty Images Scientist Max PlanckMax's father Wilhelm Planck is a lawyer and professor of law at the University of Kiel. He was married twice. The first marriage produced two children. The second time he married Max's mother Emma Patzig, with whom five children were born. She was from a pastoral family and lived in Greifswald before meeting Wilhelm Planck.
Max lived in Kiel until the age of 10. In 1867, his father received an invitation to a professorship at the University of Munich, and the family moved to the capital of Bavaria. Here the boy is sent to the Maximilian gymnasium, where he is among the best students in the class.
A great influence on the young Planck is the mathematics teacher Hermann Müller. From him, for the first time, he learns what the law of conservation of energy is. Max shows brilliant mathematical data. Classes in the gymnasium consolidated his interest in science, in particular in the study of the laws of nature.
Archive of the Max Planck SocietyAnother childhood hobby of Planck was music. He sang in a boys' choir, played several instruments, and practiced a lot at the piano. At one time he studied music theory and even tried to compose, but came to the conclusion that he would not succeed as a composer. By the end of school, Planck had already formed his addictions.
In his youth, he wanted to devote himself to music, becoming a pianist. He dreamed of studying philology, showed great interest in physics and mathematics. As a result, Max chose the exact sciences and entered the University of Munich. As a student, he does not leave music. He could be seen playing music on the organ in the student church. He directed a small choir and conducted an orchestra.
His father advises Max to turn to Professor Philipp von Jolly to help him immerse himself in the study of theoretical physics. The professor persuaded the student to abandon this idea, since, in his opinion, this science is close to completion. According to him, new discoveries are no longer worth waiting for, the main studies have been done.
Wikipedia However, Planck does not give up. He does not need discoveries, he wants to understand the foundations of physical theory and would like to deepen them as much as possible. The student begins attending lectures on experimental physics by Wilhelm von Betz. Together with Professor Philipp von Jolly, he conducts research on the permeability of heated platinum to hydrogen. Max can be seen in the classrooms of professors - mathematicians Ludwig Seidel and Gustav Bauer.
After meeting the famous physicist Hermann Helmholtz, Planck leaves to get an education at the University of Berlin. He attends lectures by the mathematician Karl Weierstrass. He studies the works of professors Helmholtz and Gustav Kirhoff, which he takes as a role model for the mastery of presenting complex material. After getting acquainted with the works of Rudolf Clasius on the theory of heat, he chooses a new direction for research - thermodynamics.
The science
In 1879, Planck received his doctorate after defending his dissertation on the second law of thermodynamics. In his work, the physicist proves that in a self-sustaining process, heat is not transferred from a cold body to a warmer one. The following year, he writes another paper on thermodynamics and receives a position as a junior assistant in the physics department at the University of Munich.
Embed from Getty Images Max Planck at a meeting at the Kaiser Wilhelm SocietyIn 1885, Planck became an adjunct professor at the University of Kiel. His research has already begun to bring him dividends in the form of international recognition. After 3 years, the scientist is invited to the University of Berlin, where he is also an adjunct professor. Along with this, he receives the post of director of the Institute of Theoretical Physics. In 1892 Max Planck became a real professor.
After 4 years, the scientist begins to study the thermal radiation of bodies. According to Planck's theory, electromagnetic radiation cannot be continuous. It comes in separate quanta, the magnitude of which depends on the emitted frequency. Max Planck derives a formula for the distribution of energy in the spectrum of an absolute black body.
In December 1900, at a meeting of the Berlin Academic Council, the physicist reports on his discovery and gives rise to a new direction - quantum theory. Already next year, on the basis of Planck's formula, the value of the Boltzmann constant is calculated. Planck manages to obtain the Avogadro constant - the number of atoms in one mole, and the scientist establishes the value of the electron charge with a high degree of accuracy.
Embed from Getty Images Max Planck and Albert EinsteinSubsequently, he contributed to the strengthening of quantum theory.
In 1919, the scientist Max Planck received the 1918 Nobel Prize for the discovery of energy quanta and the development of physics.
In 1928, he retired, but continued to collaborate with the Kaiser Wilhelm Society for Fundamental Sciences. After 2 years, the Nobel laureate becomes its president.
Religion and philosophy
Max Plan was brought up in the Lutheran spirit, and for him the values of religion always came first. Every time he ate, he said a prayer. It is known that from 1920 until the end of his life he served as a presbyter.
The scientist was against the unification of science and religion. Astrology, theosophy, spiritualism and other fashion trends fell under his criticism. At the same time, he believed that science and religion are equivalent in their significance.
Embed from Getty Images Max Planck in the LibraryHis lecture "Religion and Natural Science" from 1937 was popular, which was reflected in its repeated publications subsequently. The text became a reflection of the events in the country, which was under the rule of the Nazis.
Planck never gives a name and is forced to constantly refute rumors of a change in his faith. The scientist emphasized that he did not believe in a personal god, but at the same time remained religious.
Personal life
Max Planck first married his childhood friend Maria Merck in 1885. The marriage produced four children: two sons and twin daughters. He loved his family, was a caring husband and father. In 1909, his wife dies. After 2 years, the scientist tries to arrange his personal life for the second time and proposes to his niece Marge von Hesslin. A woman gives Max Planck another son.
Embed from Getty Images Portrait of Max PlanckA black streak begins in the scientist's biography. The eldest son dies in the First World War, in 1916, and daughters die in childbirth in 1917 and 1918. The second son from his first marriage was executed at the beginning of 1945 for participating in a conspiracy against, despite the request of a famous father.
The Nazis knew about the views of Max Planck. During a visit to Hitler, when the physicist headed the Kaiser Wilhelm Society for Fundamental Sciences, he asked him not to persecute Jewish scientists. Hitler angrily told him to his face everything he thought about the Jewish nation. After that, Planck remained silent and tried to be restrained in his thoughts.
In the winter of 1944, after an air raid by the Allied army, the scientist's house burned down completely. Manuscripts, diaries and books were destroyed in the fire. He moves to a friend Karl Stihl in Rogetz near Magdeburg.
Monument to Max Planck / Mutter Erde, Wikipedia In 1945, during a lecture in Kassel, a professor almost dies under bombs. In April, the Plancks' temporary home was also destroyed by airstrikes. The scientist and his wife go into the forest, then live with the milkman. Planck's health was deteriorating - arthritis of the spine worsened, and he walked with great difficulty.
At the request of Professor Robert Pohl, the American military sent for the Nobel laureate and took him to the safety of Göttingen. Five weeks he is in a hospital bed, and then, after recovery, he gets to work: he lectures.
Death
In July 1946, the man traveled to England for a 300th anniversary celebration. An interesting fact: the scientist was the only representative from Germany at the event. Shortly before the death of the physicist, the Kaiser Wilhelm Society was renamed the Max Planck Society, thus marking once again his contribution to science.
Instagram He continues to give lectures. In Bonn, the scientist fell ill with bilateral pneumonia, but managed to defeat the disease. In March 1947, he spoke to students for the last time. In October of the same year, Max Planck's condition deteriorated sharply, and he died. The cause of death is a stroke. He did not live up to his 90th birthday for six months. The grave of the Nobel laureate is located in the cemetery of Göttingen.
After himself, the scientist left manuscripts, books, photographs - a legacy that is priceless and continues to carry selfless service to science.
Awards and prizes
- 1914 - Helmholtz Medal
- 1915 - Order of Merit in Science and Art
- 1918 - Nobel Prize in Physics
- 1927 - Lorenz Medal
- 1927 - Franklin Medal
- 1928 - Adlerschild des Deutschen Reiches
- 1929 - Max Planck Medal
- 1929 - Copley Medal
- 1932 - Guthrie Medal and Prize
- 1933 - Harnack Medal
- 1945 - Goethe Prize
General mechanics.
The reader is offered a book by the outstanding German scientist, Nobel laureate in physics Max Planck (1858-1947), which is a textbook on general mechanics.
The author considers a separate material point, dividing the whole mechanics into two parts: the mechanics of a material point and the mechanics of a system of material points. The work is distinguished by the depth and clarity of presentation of the material and occupies an important place in the scientific heritage of the scientist.
Introduction to theoretical physics. Volume 2
Mechanics of deformable bodies.
This book, which deals with the mechanics of an elastic deformable body, is a continuation of the course "General Mechanics" by the outstanding German physicist Max Planck.
The author, with the usual skill, concisely and clearly introduces the reader to the circle of research on the theory of elasticity, hydrodynamics and aerodynamics and the theory of vortex motions. In the view of the reader of this book, the mechanics of deformable bodies should arise as a natural continuation of general mechanics, conditioned by internal necessity, and, above all, as a series of closely related, logically substantiated concepts. This will make it possible not only to study more detailed courses and specialized literature with full understanding, but also to carry out independent, deeper research.
Introduction to theoretical physics. Volume 3
Theory of electricity and magnetism.
This book, written by the outstanding German scientist, the founder of quantum mechanics, Max Planck, contains a presentation of electrical and magnetic phenomena. The work is one of the monographs on the main areas of theoretical physics, which occupy an important place in the scientific heritage of Planck.
The material of the book is distinguished by the depth and clarity of description, thanks to which it has not lost its significance even today.
Introduction to theoretical physics. Volume 4
Optics.
In the book of the outstanding German physicist Max Planck, much attention is paid to the systematic presentation and development of the main provisions of theoretical optics, and their connections with other departments of physics are presented.
In the first two parts of the work, the author considers matter as a continuous medium with continuously changing properties. In the third part, when describing the dispersion, the atomistic method of consideration is introduced. The author also outlines a natural transition to quantum mechanics based on classical theory with the help of an appropriate generalization.
Introduction to theoretical physics. Volume 5
Theory of heat.
This book is the fifth and final volume of Max Planck's Introduction to Theoretical Physics.
In the first two parts of the work of the outstanding German physicist, classical thermodynamics and the foundations of the theory of heat conduction are presented. Moreover, thermal conductivity is considered by the author as the simplest example of irreversible processes. Thanks to this point of view, the transition from thermodynamics to the theory of heat conduction turns out to be clear and natural in Planck's presentation.
The third part of the book is entirely devoted to the phenomena of thermal radiation. In subsequent chapters, the author sets out the foundations of atomistics and quantum theory, classical and quantum statistics.
Selected writings
This edition of selected works by Max Planck, one of the founders of modern physics, includes articles on thermodynamics, statistical physics, quantum theory, special relativity, and general questions of physics and chemistry.
The book is of interest to physicists, chemists, historians of physics and chemistry.
Quantum theory. Revolution in the microcosm
Max Planck was often called a revolutionary, although he was against it.
In 1900, the scientist put forward the idea that energy is not emitted continuously, but in the form of portions, or quanta. The echo of this hypothesis, which overturned the prevailing ideas, was the development of quantum mechanics, a discipline that, together with the theory of relativity, underlies the modern view of the Universe.
Quantum mechanics considers the microscopic world, and some of its postulates are so amazing that Planck himself more than once admitted that he did not keep up with the consequences of his discoveries. Teacher of teachers, for decades he stood at the helm of German science, managing to keep a spark of reason in the gloomy period of Nazism.
The principle of conservation of energy
M. Planck's book "The Principle of Conservation of Energy" is devoted to the history and justification of the law of conservation and transformation of energy, this most important law of nature for the justification of materialism.
The book has been published four times in German; from the last edition (1921) and the present translation has been made. The first part was translated by R.Ya. Steinman, the other two - S.G. Suvorov.
Translators did not want to deviate from the original style of the author when translating, but in some cases, when individual phrases of the original were extended to a whole page, they were still forced to “facilitate” this style.
Some of Planck's references to specific physical research are out of date. Therefore, in the 1908 edition, Planck made a number of additional remarks. Such remarks, though not of a principled nature, could be multiplied somewhat. Planck left the third and fourth editions unchanged from the second. The translators also considered it possible to confine themselves to the additions of the author himself to the second edition.
More significant is the absence in the reprints of the history of the law of conservation and transformation of energy over the past fifty years, which are very important for its development. The translators, of course, could not exhaust this story with separate remarks; it requires independent research, which is beyond the scope of this work. However, some very significant moments of the subsequent development of the law, namely, the struggle of various trends in physics around the assessment of the meaning of the law and its interpretation, are highlighted in the article by S.G. Suvorov. In it, the reader will also find an assessment of the book by M. Planck.
Why Max Planck, choosing between physics and music, preferred science, what do his studies and films about kung fu have in common, why did he quarrel with Einstein and how did he suffer from the First and Second World Wars, tells the column "How to get a Nobel Prize".
Nobel Prize in Physics 1918. The wording of the Nobel Committee: "In recognition of his merits in the development of physics through the discovery of energy quanta."
When you write the biographies of Nobel laureates in chronological order, it is surprising how varied the amount of information is available about the great scientists. In one case, one has to “dig into” journal articles, trying to understand texts in languages other than English and Russian, while in the other, on the contrary, there are so many important facts that one has to arrange a strict competition for them.
The case of the 1918 Nobel laureate in physics clearly falls into the second category. Max Planck had been nominated for the prize every year since 1910 and received the award relatively quickly, despite the fact that much of the physics community, including many of the original prize winners, was far from ready to acknowledge the advent of new physics. Even under the weight of accumulated facts.
Max Planck is a man whose name has now become a household name for German science (remember the Max Planck Society, an analogue of our Academy of Sciences). He was practically deified by German science during his lifetime (the Max Planck medal - the first was received by Planck himself and Einstein - and the Max Planck Institute of Physics appeared during the scientist's lifetime). Our hero was a "man of origin". His father, Wilhelm Planck, represented an ancient noble family, many of whose members were famous figures in science and culture. For example, Max's grandfather Heinrich Ludwig, like his great-grandfather Gottlieb Jakob, taught theology in Göttingen. Mom, Emma Patzig, came from a church family.
Entrance to the building of the Max Planck Society (Munich)
Wikimedia Commons
He was born on April 23, 1858 in Kiel, the capital of Holstein (this is where Emperor Peter III, husband of Catherine II, came from). Germany and Denmark constantly argued for Kiel, even fought for it. The Planck family spent the first nine years of the life of the future great scientist in this city, and Max remembered for the rest of his life the entry of Prussian and Austrian troops into the city in 1864. In general, the wars constantly hit next to Planck - at the closest. In World War I, in 1916, his eldest son Karl died near Verdun, in January 1945 the Nazis hanged his second son Erwin (he was suspected of being involved in the conspiracy of Colonel Stauffenberg). Allied bombings almost killed him during a lecture, filling him up for several hours in a bomb shelter, at the end of the war they ruined his estate, his huge library disappeared somewhere ...
But for now, the year is 1867, and the father of the young Planck receives an invitation from Munich. The position of professor of law at the famous University of Munich turned out to be very tempting, and the family moved to Bavaria. Here Max Planck went to study at the very prestigious Maximilian Gymnasium, where he became the first student.
Maximilian Gymnasium
Wikimedia Commons
And right in the structure of Propp's fairy tale or a film about a kung fu master, it was here that a more experienced and wise adviser appeared, sharing some of his wisdom. Mathematics teacher Hermann Müller became such a fabulous mentor. He discovered a talent for mathematics in a young man and gave him the first lessons in the amazing beauty of the laws of nature: it was from Müller that Planck learned about the law of conservation of energy, which amazed him forever. It must be said that by the time he graduated from school, the outline of the fairy tale continued: he found himself at a crossroads. Of course, there was no stone with inscriptions, but, in addition to obvious abilities in physics and mathematics, Planck showed remarkable musical talent. Perhaps his choice was influenced by the fact that Max Planck, with an excellent voice and a wonderful technique of playing the piano, realized that he was not the best composer.
Planck chose physics and in 1874 entered the University of Munich. True, he did not quit playing, singing and conducting. Physics is physics. It also had to make a choice: in which of the areas of science to go.
Wilhelm Planck sent his son to Professor Philip Jolly. The young man gravitated towards theoretical physics and asked the famous scientist how he likes such a choice. Jolly, trying to dissuade him, told Planck the same phrase, which is now worn out to holes: they say, boy, don’t go into theoretical physics: all the discoveries have already been made here, all the formulas have been derived, there are a few particulars left to cover, and that’s it. True, this is usually quoted with intonation, they say, the young man heroically rushed to fight against the inertia of physics of that time. But no.
Max Planck in 1878
public domain
The young man was delighted: he was not at all going to make new discoveries. As Planck later explained his decision, he was only going to understand the knowledge already accumulated by physics and clarify inaccuracies. Who knew that in the course of the refinement, the entire building of physics of 1874 would collapse.
Here is how Planck himself wrote about himself as a young man in his Scientific Autobiography: “From my youth, I was inspired to engage in science by the realization of the far from self-evident fact that the laws of our thinking coincide with the laws that take place in the process of receiving impressions from the outside world, and that, therefore, a person can judge these regularities with the help of pure thinking. The essential thing here is that the external world is something independent of us, absolute, which we oppose, and the search for laws relating to this absolute seems to me the most beautiful task in the life of a scientist.
Theoretical physics brought him to Berlin, where he studied under the greats Helmholtz and Kirchhoff. True, Planck was disappointed with lectures on physics at the University of Berlin and sat down to the original work of his teachers. Works on the theory of heat by Rudolf Clausius were soon added to Helmholtz and Kirchhoff. This is how the field of scientific work of the young theorist Max Planck was determined - thermodynamics. He enthusiastically undertakes to "clarify" the details: he reformulates the second law of thermodynamics, writes new definitions of entropy ...
Portrait of Hermann Helmholtz
Hans Schadow/Wikimedia Commons
Here we take the liberty of quoting Max von Laue from 1947: “Today's physics bears a very different imprint than the physics of 1875, when Planck devoted himself to it; and in the greatest of these upheavals, Planck played the first decisive role. It was an amazing set of circumstances. To think, an eighteen-year-old applicant decided to devote himself to a science about which the most competent person he could ask would say that it had little promise. In the process of studying, he chooses a branch of this science, which is not at all respected by related sciences, but within this branch - a special area in which no one is interested. Neither Helmholtz, nor Kirchhoff, nor Clausius, who were closest to this, even read his first works, and yet he continues on his way, following an inner call, until he encounters a problem that many others already tried in vain to decide and for which - as it turns out - it was the path he had chosen that was the best preparation. As a result, he was able, based on measurements of radiation, to discover the law of radiation, which bears his name for all time. He communicated it on 19 October 1900 to the Physical Society in Berlin."
What did Planck discover and what problem did he solve?
Back in the 1860s, one of Planck's teachers, Gustav Kirchhoff, came up with a model object for thought experiments in thermodynamics - an absolutely black body. By definition, a blackbody is a body that absorbs absolutely all the radiation that falls on it. Kirchhoff showed that an absolute body is also the best possible radiator. But it radiates heat energy.
Rudolf Clausius
Wikimedia Commons
In 1896, the 1911 Nobel laureate, Wilhelm Wien, formulated his second law, which explained the shape of the black body radiation energy distribution curve based on Maxwell's equations. And this is where the controversy began. Wien's second law turned out to be valid for shortwave radiation. Regardless of Veen, William Strutt, Lord Rayleigh, got his formula, but it "worked" on long wavelengths.
Type of spectral curves given by Planck's and Wien's laws of radiation at various temperatures. It can be seen that the difference between the curves increases in the long-wavelength region
Planck was able, using the model of the simplest linear harmonic resonator, to derive a formula that combined the Wien formula and the Rayleigh formula. On this formula, which later became Planck's formula, he made a report on October 19. However, if Max Planck had done just that, he would hardly have been revered so highly. Yes, after the report in October, several physicists found him and told him: theory is ideally combined with practice. But this only meant that he had successfully chosen a formula that explained a highly specialized problem. This was not enough for Planck, and he took up the theoretical justification of the empirically found formula. On December 14 of the same year, he again spoke at the Physical Society and made a report from which it follows: the energy of a completely black body should be emitted in portions. Quantum.
The German physicist Max Karl Ernst Ludwig Planck was born in Kiel (then belonging to Prussia), in the family of civil law professor Johann Julius Wilhelm von Planck, professor of civil law, and Emma (nee Patzig) Planck. As a child, the boy learned to play the piano and organ, revealing extraordinary musical abilities. In 1867, the family moved to Munich, and there P. entered the Royal Maximilian Classical Gymnasium, where an excellent teacher of mathematics first aroused in him an interest in the natural and exact sciences. At the end of the gymnasium in 1874, he was going to study classical philology, tried his hand at musical composition, but then gave preference to physics.
For three years, P. studied mathematics and physics at Munich and a year - at the University of Berlin. One of his professors in Munich, experimental physicist Philipp von Jolly, turned out to be a bad prophet when he advised the young P. to choose another profession, since, according to him, there was nothing fundamentally new in physics that could be discovered. This point of view, widely held at that time, arose under the influence of the extraordinary successes that scientists in the XIX century. achieved in increasing our knowledge of physical and chemical processes.
When he was in Berlin, P. acquired a broader view of physics through the publications of prominent physicists Hermann von Helmholtz and Gustav Kirchhoff, as well as articles by Rudolf Clausius. Acquaintance with their works contributed to the fact that the scientific interests of P. for a long time focused on thermodynamics - a field of physics in which, on the basis of a small number of fundamental laws, the phenomena of heat, mechanical energy and energy conversion are studied. Dr. P. received in 1879, having defended at the University of Munich a dissertation on the second law of thermodynamics, stating that no continuous self-sustaining process can transfer heat from a colder body to a warmer one.
The following year, P. wrote another work on thermodynamics, which earned him the position of junior assistant at the Faculty of Physics, University of Munich. In 1885 he became an adjunct professor at the University of Kiel, which strengthened his independence, strengthened his financial position and provided more time for scientific research. Work P. on thermodynamics and its applications to physical chemistry and electrochemistry won him international recognition. In 1888 he became associate professor at the University of Berlin and director of the Institute for Theoretical Physics (the post of director was created especially for him). He became a full (real) professor in 1892.
Since 1896, Mr.. P. became interested in the measurements made at the State Institute of Physics and Technology in Berlin, as well as the problems of thermal radiation of bodies. Any body containing heat emits electromagnetic radiation. If the body is hot enough, then this radiation becomes visible. When the temperature rises, the body first becomes red-hot, then becomes orange-yellow, and finally white. The radiation emits a mixture of frequencies (in the visible range, the frequency of the radiation corresponds to the color). However, the radiation of a body depends not only on temperature, but also to some extent on surface characteristics such as color and structure.
As an ideal standard for measurement and theoretical studies, physicists have adopted an imaginary absolute black body. By definition, a body is called absolutely black if it absorbs all radiation falling on it and reflects nothing. The radiation emitted by a completely black body depends only on its temperature. Although such an ideal body does not exist, a closed shell with a small hole (for example, a properly designed furnace, the walls and contents of which are in equilibrium at the same temperature) can serve as an approximation to it.
One of the proofs of the blackbody characteristics of such a shell is as follows. The radiation incident on the hole enters the cavity and, reflected from the walls, is partially reflected and partially absorbed. Since the probability that the radiation as a result of numerous reflections will go out through the hole is very small, it is almost completely absorbed. The radiation originating in the cavity and emerging from the hole is considered to be equivalent to the radiation emitted by a hole-sized area on the surface of a black body at the temperature of the cavity and shell. Preparing their own research, P. read the work of Kirchhoff on the properties of such a shell with a hole. An exact quantitative description of the observed distribution of radiation energy in this case is called the blackbody problem.
As experiments with a black body have shown, a plot of energy (brightness) versus frequency or wavelength is a characteristic curve. At low frequencies (large wavelengths), it is pressed against the frequency axis, then at some intermediate frequency it reaches a maximum (a peak with a rounded top), and then at higher frequencies (short wavelengths) it decreases. As the temperature rises, the curve retains its shape, but shifts towards higher frequencies. Empirical relationships were established between the temperature and frequency of a peak on a blackbody radiation curve (Wien's displacement law, named after Wilhelm Wien) and between temperature and all radiated energy (the Stefan-Boltzmann law, named after the Austrian physicists Josef Stefan and Ludwig Boltzmann ), but no one was able to derive the blackbody radiation curve from the basic principles known at the time.
Wien has succeeded in obtaining a semi-empirical formula that can be adjusted so that it describes the curve well at high frequencies, but misrepresents its behavior at low frequencies. J. W. Strett (Lord Rayleigh) and the English physicist James Jeans applied the principle of equal distribution of energy over the frequencies of oscillations of oscillators enclosed in the space of a black body, and came to another formula (the Rayleigh-Jeans formula). It reproduced the black body radiation curve well at low frequencies, but diverged from it at high frequencies.
P. under the influence of the theory of the electromagnetic nature of light by James Clerk Maxwell (published in 1873 and experimentally confirmed by Heinrich Hertz in 1887) approached the problem of a black body from the point of view of the distribution of energy between elementary electrical oscillators, the physical form of which is not specified in any way. Although at first glance it may seem that his chosen method resembles the conclusion of Rayleigh - Jeans, P. rejected some of the assumptions adopted by these scientists.
In 1900, after a long and persistent attempt to create a theory that would satisfactorily explain the experimental data, P. managed to derive a formula that, as found by experimental physicists from the State Institute of Physics and Technology, consistent with the measurement results with remarkable accuracy. The Wien and Stefan–Boltzmann laws also followed from Planck's formula. However, in order to derive his formula, he had to introduce a radical concept that runs counter to all established principles. The energy of Planck oscillators does not change continuously, as follows from traditional physics, but can only take on discrete values that increase (or decrease) in finite steps. Each energy step is equal to some constant (now called Planck's constant) multiplied by the frequency. Discrete portions of energy were subsequently called quanta. Introduced P. hypothesis marked the birth of quantum theory, which made a real revolution in physics. Classical physics, in contrast to modern physics, now means "physics before Planck."
P. was by no means a revolutionary, and neither he nor other physicists were aware of the deep meaning of the concept of "quantum". For P. quantum was just a means to derive a formula that gives satisfactory agreement with the radiation curve of a completely black body. He repeatedly tried to reach agreement within the classical tradition, but without success. At the same time, he noted with pleasure the first successes of quantum theory, which followed almost immediately. His new theory included, in addition to Planck's constant, other fundamental quantities such as the speed of light and a number known as the Boltzmann constant. In 1901, based on experimental data on blackbody radiation, P. calculated the value of the Boltzmann constant and, using other known information, obtained the Avogadro number (the number of atoms in one mole of an element). Based on the number of Avogadro, P. was able to find with remarkable accuracy the electric charge of the electron.
The position of quantum theory was strengthened in 1905, when Albert Einstein used the concept of a photon - a quantum of electromagnetic radiation - to explain the photoelectric effect (the emission of electrons from a metal surface illuminated by ultraviolet radiation). Einstein suggested that light has a dual nature: it can behave both like a wave (as all previous physics convinces us) and as a particle (as evidenced by the photoelectric effect). In 1907, Einstein further strengthened the position of quantum theory, using the concept of quantum to explain the mysterious discrepancies between theoretical predictions and experimental measurements of the specific heat of bodies - the amount of heat required to raise the temperature of one unit mass of a solid body by one degree.
Another confirmation of the potential power introduced by P. innovation came in 1913 from Niels Bohr, who applied quantum theory to the structure of the atom. In Bohr's model, electrons in an atom could only be at certain energy levels, determined by quantum limitations. The transition of electrons from one level to another is accompanied by the release of the energy difference in the form of a radiation photon with a frequency equal to the photon energy divided by Planck's constant. In this way, the characteristic spectra of radiation emitted by excited atoms were given a quantum explanation.
In 1919, Mr.. P. was awarded the Nobel Prize in Physics for 1918. "in recognition of his merits in the development of physics through the discovery of energy quanta." As stated by A.G. Ekstrand, a member of the Royal Swedish Academy of Sciences, at the award ceremony, "P.'s radiation theory is the brightest of the guiding stars of modern physical research, and it will take, as far as one can judge, a lot of time before the treasures that were mined by his genius run out" . In the Nobel lecture given in 1920, P. summed up his work and admitted that "the introduction of the quantum has not yet led to the creation of a true quantum theory."
20s witnessed the development of Erwin Schrödinger, Werner Heisenberg, P.A.M. Dirac and others of quantum mechanics - equipped with a complex mathematical apparatus of quantum theory. P. did not like the new probabilistic interpretation of quantum mechanics, and, like Einstein, he tried to reconcile predictions based only on the principle of probability, with the classical ideas of causality. His aspirations were not destined to come true: the probabilistic approach withstood.
P.'s contribution to modern physics is not limited to the discovery of the quantum and the constant that now bears his name. Einstein's special theory of relativity, published in 1905, made a strong impression on him. Among his other achievements is his proposed derivation of the Fokker-Planck equation, which describes the behavior of a system of particles under the action of small random impulses (Adrian Fokker is a Dutch physicist who improved the method first used by Einstein to describe Brownian motion - the chaotic zigzag motion of the smallest particles suspended in a liquid ). In 1928, at the age of seventy, Planck went into obligatory formal retirement, but did not sever his ties with the Kaiser Wilhelm Society for Fundamental Sciences, of which he became president in 1930. And into his eighth decade, he continued his research activities.
P.'s personal life was marked by tragedy. His first wife, née Maria Merck, whom he married in 1885 and who bore him two sons and two twin daughters, died in 1909. Two years later he married his niece Marga von Hesslin, by whom he also had a son. The eldest son P. died in the First World War, and in subsequent years, both of his daughters died in childbirth. The second son from his first marriage was executed in 1944 for participating in a failed plot against Hitler.
As a person of established views and religious beliefs, and simply as a just person, P. after Hitler came to power in 1933 publicly defended Jewish scientists who were expelled from their posts and forced to emigrate. At a scientific conference, he hailed Einstein, who had been anathematized by the Nazis. When P. as president of the Kaiser Wilhelm Society for Fundamental Sciences paid an official visit to Hitler, he took advantage of this opportunity to try to stop the persecution of Jewish scientists. In response, Hitler launched a tirade against Jews in general. In the future, P. became more restrained and kept silent, although the Nazis, of course, knew about his views.
As a patriot who loves his motherland, he could only pray that the German nation would return to normal life. He continued to serve in various German learned societies in the hope of saving at least some small amount of German science and enlightenment from total annihilation. After his house and personal library were destroyed during an air raid on Berlin, P. and his wife tried to find refuge in the Rogets estate near Magdeburg, where they found themselves between the retreating German troops and the advancing Allied forces. In the end, the Plancks were discovered by American units and taken to the then safe Göttingen.
P. died in Göttingen on October 4, 1947, six months before his 90th birthday. Only his first and last name and the numerical value of Planck's constant are engraved on his tombstone.
Like Bohr and Einstein, P. deeply interested in the philosophical problems associated with causality, ethics and free will, and spoke on these topics in print and before professional and non-professional audiences. Acting pastor (but not having a priesthood) in Berlin, P. was deeply convinced that science complements religion and teaches truthfulness and respect.
Throughout his life, P. carried a love of music that flared up in him in early childhood. An excellent pianist, he often played chamber works with his friend Einstein until he left Germany. P. was also a keen mountaineer and spent almost every vacation in the Alps.
In addition to the Nobel Prize, P. was awarded the Copley Medal of the Royal Society of London (1928) and the Goethe Prize in Frankfurt am Main (1946). The German Physical Society named after him its highest award, the Planck Medal, and P. himself was the first recipient of this honorary award. In honor of his 80th birthday, one of the minor planets was named Plankiana, and after the end of the Second World War, the Kaiser Wilhelm Society for Fundamental Sciences was renamed the Max Planck Society. P. was a member of the German and Austrian Academies of Sciences, as well as scientific societies and academies in England, Denmark, Ireland, Finland, Greece, the Netherlands, Hungary, Italy, the Soviet Union, Sweden, Ukraine and the United States.
