|
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese|
BIOGRAPHIES OF GREAT SCIENTISTS
Helmholtz Hermann Ludwig Ferdinand. Biography of a scientist
Directory / Biographies of great scientists
Hermann Helmholtz is one of the greatest scientists of the XNUMXth century. Physics, physiology, anatomy, psychology, mathematics... In each of these sciences, he made brilliant discoveries that brought him worldwide fame. Hermann Ludwig Ferdinand Helmholtz was born on August 31, 1821 in the family of a Potsdam gymnasium teacher. At the request of his father, in 1838 Herman entered the Friedrich Wilhelm Military Medical Institute to study medicine. Under the influence of the famous physiologist Johann Müller, Helmholtz devoted himself to the study of physiology and, after attending the course of the institute, defended his doctoral dissertation in 1842 on the structure of the nervous system. In this work, the twenty-two-year-old doctor proved for the first time the existence of integral structural elements of the nervous tissue, later called neurons. In the same year, Herman was appointed as an intern at a hospital in Berlin. Since 1843, Helmholtz began his career as a Potsdam military doctor. He lived in the barracks and got up at five o'clock in the morning at the signal of the cavalry trumpet. But the squadron surgeon of the hussar regiment also found time for science. In 1845, he said goodbye to military service and went to Berlin to prepare for the state examinations for the title of doctor. Helmholtz is hard at work in the home physics laboratory of Gustav Magnus. A. G. Stoletov, who sensitively caught the turning point in the scientific development of Germany in the forties, wrote: "Magnus's home laboratory - the first example of a physical laboratory - is becoming a hotbed of experimental physicists." Subsequently, the pupil of this laboratory, Helmholtz, becomes the successor of Magnus and transfers the laboratory to the building of the University of Berlin, where it turns into a world scientific center. Another teacher of Helmholtz in Berlin was Johann Müller. Much later on November 2, 1871, at the celebration of Helmholtz on the occasion of his seventieth birthday, he delivered a speech in which he described his scientific path. He indicated that, under the influence of Johann Müller, he became interested in the question of the mysterious being of life force. Reflecting on this problem, Helmholtz, in his last year as a student, came to the conclusion that the theory of vital force "attributes to every living body the properties of the so-called perpetuum mobile." Helmholtz was familiar with the problem of perpetual motion since his school years, and in his student years "in his free moments ... he searched for and looked through the works of Daniel Bernoulli, d'Alembert and other mathematicians of the last century." "Thus," said Helmholtz, "I came across the question: 'What relation must exist between the various forces of nature, if it is assumed that perpetuum mobile is impossible at all?' And further: 'Do all these relations actually hold?'" In Müller's journal, Helmholtz published in 1845 the work "On the Expenditure of Substance under the Action of Muscles". In the same 1845, young scientists grouped around Magnus and Müller formed the Berlin Physical Society. Helmholtz also entered it. Since 1845, the society, which later turned into the German Physical Society, began to publish the first abstract journal "Uspekhi fiziki". The scientific development of Helmholtz thus took place in a favorable environment of increased interest in natural science in Berlin. Already in the first volume of Uspekhi Fiziki, 1845, published in Berlin in 1847, Helmholtz's review of the theory of physiological thermal phenomena was published. On July 23, 1847, he made a report "On the Conservation of Force" at a meeting of the Berlin Physical Society. In the same year it was published as a separate pamphlet. The authorities at that time "were inclined to reject the justice of the law; in the midst of the zealous struggle that they waged with Hegel's natural philosophy, my work was also considered fantastic philosophizing ...". However, Helmholtz was not alone, he was supported by young scientists, and, above all, the future famous physiologist Dubois Reymond and the young Berlin Physical Society. As for his attitude to the work of Mayer and Joule's predecessors, Helmholtz repeatedly recognized the priority of Mayer and Joule, emphasizing, however, that he was not familiar with Mayer's work, and knew Joule's work insufficiently. Unlike his predecessors, he connects the law with the principle of the impossibility of a perpetual motion machine. Matter Helmholtz considers as passive and motionless. In order to describe the changes taking place in the world, it must be endowed with forces both attractive and repulsive. "Natural phenomena," says Helmholtz, "should be reduced to motions of matter with unchanging driving forces that depend only on spatial relationships." Thus, the world, according to Helmholtz, is a collection of material points interacting with each other with central forces. These forces are conservative, and Helmholtz puts the principle of conservation of manpower at the head of his research. Mayer's principle "nothing comes from nothing" Helmholtz replaces with a more specific provision that "it is impossible, given the existence of any arbitrary combination of bodies, to continuously obtain a driving force from nothing." The principle of conservation of living force in its formulation reads: "If any number of moving material points moves only under the influence of such forces that depend on the interaction of points on each other or which are directed towards fixed centers, then the sum of the living forces of all points taken together will remain one and the same same at all moments of time at which all points receive the same relative positions with respect to each other and with respect to existing fixed centers, whatever their trajectories and velocities in the intervals between the corresponding moments. Having formulated this principle, Helmholtz considers its applications in various special cases. Considering electrical phenomena, Helmholtz finds an expression for the energy of point charges and shows the physical meaning of the function called the Gauss potential. Further, he calculates the energy of a system of charged conductors and shows that when the Leyden jars are discharged, heat is released that is equivalent to the stored electrical energy. He showed at the same time that the discharge is an oscillatory process and electrical oscillations "become smaller and smaller, until finally the living force is destroyed by the sum of the resistances." Then Helmholtz considers galvanism. Helmholtz analyzes energy processes in galvanic sources, in thermoelectric phenomena, laying the foundation for the future thermodynamic theory of these phenomena. Considering magnetism and electromagnetism, Helmholtz, in particular, gives his well-known derivation of the expression for the electromotive force of induction, based on Neumann's research and based on Lenz's law. In his work, Helmholtz, unlike Mayer, focuses on physics and speaks only very briefly and concisely about biological phenomena. Nevertheless, it was this work that opened the way for Helmholtz to the Department of Physiology and General Pathology of the Medical Faculty of the University of Königsberg, where in 1849 he received the post of extraordinary professor. Helmholtz held this position until 1855, when he moved to Bonn as a professor of anatomy and physiology. In 1858, Helmholtz became professor of physiology at Heidelberg, where he worked extensively and successfully on the physiology of vision. These studies have significantly enriched the field of knowledge and practical medicine. The result of these studies was the famous "Physiological Optics" by Helmholtz, the first issue of which appeared in 1856, the second - in 1860, and the third - in 1867. The eye is one of the most remarkable organs of our body. They knew about his work before, compared it with the work of a photographic apparatus. But for a complete elucidation of even the physical side of vision, a rough comparison with a camera is not enough. It is necessary to solve a number of complex problems from the field not only of physics, but also of physiology and even psychology. They had to be resolved with a live eye, and Helmholtz managed to do it. He built a special apparatus, amazing in its simplicity (ophthalmometer), which made it possible to measure the curvature of the cornea of the posterior and anterior surfaces of the lens. Thus, the refraction of rays in the eye was studied. We see objects painted in one color or another, our vision is colored. What is at its core? The study of the eye showed that the retina has three main light-sensing elements: one of them is most strongly irritated by red rays, the other by green rays, and the third by blue rays. Any color causes a stronger irritation of one of the elements and a weaker one of the others. Combinations of irritations create all that play of colors that we see around us. To explore the bottom of the living eye, Helmholtz made a special device: an eye mirror (ophthalmoscope). This device has long been a must-have equipment for every eye doctor. Helmholtz did a lot to study the eye and vision: he created physiological optics - the science of the eye and vision. Here, in Heidelberg, Helmholtz carried out his classical studies on the rate of propagation of nervous excitation. Frogs for dissection have been on the scientist's laboratory table many times. He studied on them the speed of propagation of excitation along the nerve. The nerve was irritated by the current, the resulting excitation reached the muscle, and it contracted. Knowing the distance between these two points and the difference in time, it is possible to calculate the speed of propagation of excitation along the nerve. It turned out to be quite small, only from 30 to 100 m/s. Seems like a very simple experience. It looks simple now that Helmholtz designed it. And before him, it was argued that this speed cannot be measured: it is a manifestation of a mysterious "life force" that cannot be measured. Helmholtz did no less for the study of hearing and the ear (physiological acoustics). In 1863, his book "The Teaching of Sound Sensations as the Physiological Basis of Acoustics" was published. And here, before Helmholtz's research, much related to hearing was studied very poorly. They knew how sound originated and propagated, but very little was known about the effects that sounds have on objects capable of vibrating. Helmholtz was the first to tackle this complex phenomenon. Having created the theory of resonance, he then created on its basis the doctrine of auditory sensations, our voice, and musical instruments. Studying the phenomena of oscillations, Helmholtz also developed a number of issues of great importance for the theory of music, and gave an analysis of the causes of musical harmony. The example of Helmholtz shows the great importance of the breadth of the scientist's outlook, the richness and diversity of his knowledge and interests. In the same place, in Heidelberg, his classical works on hydrodynamics and the foundations of geometry were published. From March 1871, Helmholtz became a professor at the University of Berlin. He created a physical institute, where physicists from all over the world came to work. After moving to Berlin, Helmholtz devotes himself exclusively to physics, and studies its most complex areas: electrodynamics, in which, based on the ideas of Faraday, he develops his own theory, then hydrodynamics and the phenomena of electrolysis in connection with thermochemistry. Particularly remarkable are his works on hydrodynamics, begun as early as 1858, in which Helmholtz gives a theory of vortex motion and fluid flow and in which he manages to solve several very difficult mathematical problems. In 1882, Helmholtz formulates the theory of free energy, in which he decides how much of the total molecular energy of a system can be converted into work. This theory has the same meaning in thermochemistry as the Carnot principle in thermodynamics. In 1883, Emperor Wilhelm grants Helmholtz the title of nobility. In 1884, Helmholtz published the theory of anomalous dispersion, and a little later, several important works on theoretical mechanics. Works on meteorology belong to the same time. In 1888, Helmholtz was appointed director of the newly established government Institute of Physics and Technology in Charlottenburg - the Center for German Metrology, in the organization of which he took an active part. At the same time, the scientist continues to lecture on theoretical physics at the university. Helmholtz had many students; Thousands of students listened to his lectures. Many young scientists came to work in his laboratory and learn the art of experiment. Many Russian scientists can be considered his students - physiologists E. Adamyuk, N. Bakst, F. Zavarykin, I. Sechenov, physicists P. Lebedev, P. Zidov, R. Kolli, A. Sokolov, N. Shidder. Unfortunately, not only joyful events awaited Helmholtz in old age. His son Robert, a promising young physicist, died untimely in 1889, leaving work on the radiation of burning gases. The most recent works of the scientist, written in 1891-1892, relate to theoretical mechanics. Helmholtz died on September 8, 1894. Author: Samin D.K.
▪ Schrödinger Erwin. Biography
Machine for thinning flowers in gardens
02.05.2024 Advanced Infrared Microscope
02.05.2024 Air trap for insects
01.05.2024
▪ Dark matter particles can be ultralight ▪ To decipher the human genome
▪ section of the site Power supply. Article selection ▪ article A series of magical changes to a cute face. Popular expression ▪ article Where did the first and last British soldiers killed in World War I meet? Detailed answer ▪ article Jasmine yellow. Legends, cultivation, methods of application ▪ article Flights of objects. Focus Secret
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua |
We recommend interesting articles Section 
See other articles Section 
Latest news of science and technology, new electronics:
All languages of this page