|
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese|
MOST IMPORTANT SCIENTIFIC DISCOVERIES
Electron. History and essence of scientific discovery
Directory / The most important scientific discoveries Clear and precise ideas about the atomic structure of electricity appeared in W. Weber, which he developed them in a number of works, starting in 1862: "With the general distribution of electricity, it can be assumed that an electric atom is associated with every weighty atom." In connection with this, he develops views on the conductivity of current in metals, which differ from electronic ones only in that he considers positive electricity atoms to be mobile. He also expressed the idea of a molecular interpretation of Joule-Lenz heat: "The living force of all the molecular currents contained in the conductor increases with the passage of current in proportion to the resistance and in proportion to the square of the current strength." These and similar statements by Weber gave rise to A.I. Bachinsky to call Weber one of the creators of the electronic theory, and O.D. Khvol'son to place his name in the opening paragraph of the chapter on the electronic theory of the conduction of metals. But it should be noted that Weber does not yet connect his "electric atom" with the specific facts of electrolysis. This connection was first established Maxwell in the first volume of his Treatise. But Maxwell did not develop this important idea. On the contrary, he argued that the idea of a molecular charge would not survive in science. In 1874, the Irish physicist Stoney, at a meeting of the British Association, drew attention to the existence in nature of three "natural units": the speed of light, the gravitational constant and the charge of the "electric atom". Regarding this last unit, he said: "Finally, nature endowed us in the phenomena of electrolysis with a quite definite amount of electricity, independent of the bodies with which it is connected." Stoney estimated this charge by dividing the amount of electricity released during the decomposition of a cubic centimeter of hydrogen by the number of its atoms according to the then data, and received a value of the order of 10 to the minus twentieth power of electromagnetic units. Stoney proposed to call this electric atom "electron". April 5 1881 years Helmholtz In his famous speech, he declared: "If we admit the existence of chemical atoms, then we are forced to conclude from here further that electricity, both positive and negative, is also divided into certain elemental quantities, which play the role of atoms of electricity." In 1869, Gittorf, having obtained a vacuum with a degree of rarefaction below one millimeter in a discharge tube, noticed that the dark cathode space quickly spreads throughout the tube, as a result of which the walls of the tube begin to strongly fluoresce. He noticed that the glow of the tube is shifted under the influence of a magnet. Ten years after the observations of Giettorf, the works of W. Crooks appeared. According to Crookes, a particle of radiant matter is ejected from the electrodes with great speed. The dark cathode space is a space in which negative gas molecules move freely, flying from the cathode and held at its border by counter positive molecules. However, German physicists did not accept Crookes's point of view. E. Goldstein in 1880 showed that the identification of the dimensions of the dark cathode space with the mean free path is incorrect. He showed that cathode rays do not end at all at the boundary of the dark layer; at high rarefaction they also penetrate the luminous space of the anode. Austrian scientist V.F. Gintl in the same year hypothesized that cathode rays are a stream of metal particles pulled out of the cathode by an electric current, which move in a straight line. This point of view was supported and developed further by Pulua. In the same 1880, E. Wiedemann identified cathode rays with ethereal vibrations of such a short wavelength. In his opinion, they do not produce a luminous effect; however, falling on weighty matter, they slow down and turn into visible light. Lenard's experiments played a decisive role in strengthening the ethereal wave theory of cathode rays. He convincingly proved that the cathode rays can go outside while maintaining the vacuum in the tube, i.e., these rays cannot be particles of gas, as Crookes suggested. But this is not enough. Cathode rays in air produce a luminous and photographic effect. Lenard managed to get in the stream he released a photograph of an object sealed in a hermetically sealed aluminum box with thin walls. Observing the deflection of the emitted beam by the magnet, he found that this deflection does not depend on the type of gas, and most importantly, that there remains a part of the rays that are not deflected by the magnet. Lenard was the first physicist to observe the action of x-rays and even received the first x-ray. But he failed to fully understand his discovery and characterized it as proof of the wave nature of cathode rays. His experiment was fraught with great opportunities that the scientist did not use. The Wiedemann-Hertz-Lenard theory was greatly shaken in 1895 by the experience of Perrin (1870–1942), who attempted to detect the charge of cathode rays. To this end, he placed a Faraday cylinder in the discharge tube against the cathode, connected to an electrometer. During the passage of the discharge, the cylinder was charged negatively. From this, Perrin concluded that "the transfer of negative charges is inseparable from cathode rays." Perrin established with certainty the transfer of charge by cathode rays and believed that this fact is difficult to reconcile with the theory of vibrations, while it agrees very well with the theory of expiration. Therefore, he believed that "if the theory of expiration can refute all the objections that it has raised, it must be recognized as really suitable." However, in order to refute all objections, it was necessary to radically change the views on the structure of matter and allow the existence of particles of smaller atoms in nature. The English physicist Joseph Thomson (1856–1940) entered the history of science as the man who discovered the electron. Once he said: "Discoveries are due to the sharpness and power of observation, intuition, unshakable enthusiasm until the final resolution of all the contradictions that accompany pioneer work." Joseph John Thomson was born in Manchester. Here, in Manchester, he graduated from Owens College, and in 1876-1880 he studied at the University of Cambridge at the famous Trinity College (Trinity College). In January 1880, Thomson successfully passed his final exams and began working at the Cavendish Laboratory. His first article, published in 1880, was devoted to the electromagnetic theory of light. The following year, two papers appeared, one of which laid the foundation for the electromagnetic theory of mass. Thomson was obsessed with experimental physics. Obsessed in the best sense of the word. Thomson's scientific achievements were highly appreciated by Rayleigh, director of the Cavendish laboratory. Leaving in 1884 as director, he did not hesitate to recommend Thomson as his successor. From 1884 to 1919 Thomson directed the Cavendish laboratory. During this time it has become a major center of world physics, an international school of physicists. Here they began their scientific journey Rutherford, Bohr, Langevin and many others, including Russian scientists. Thomson's research program was broad: questions of the passage of electric current through gases, the electronic theory of metals, the study of the nature of various kinds of rays ... Taking up the study of cathode rays, Thomson first of all decided to check whether his predecessors, who had achieved the deflection of rays by electric fields, had carried out the experiments with sufficient care. He conceives a repeated experiment, designs special equipment for it, monitors the accuracy of the execution of the order himself, and the expected result is obvious. In the tube designed by Thomson, the cathode rays obediently attracted to the positively charged plate and clearly repelled from the negative one. That is, they behaved as it was supposed to be for a stream of fast-moving tiny corpuscles charged with negative electricity. Excellent result! He could certainly put an end to all disputes about the nature of cathode rays. But Thomson did not consider his research complete. Having determined the nature of the rays qualitatively, he wanted to give an exact quantitative definition of the corpuscles that make them up. Inspired by the first success, he designed a new tube: a cathode, accelerating electrodes in the form of rings and plates, to which a deflecting voltage could be applied. On the wall opposite the cathode, he deposited a thin layer of a substance capable of glowing under the impact of incident particles. It turned out to be the ancestor of cathode ray tubes, so familiar to us in the age of televisions and radars. The purpose of Thomson's experiment was to deflect a bunch of corpuscles with an electric field and compensate for this deflection with a magnetic field. The conclusions he came to as a result of the experiment were amazing. First, it turned out that the particles fly in the tube with enormous velocities close to the speed of light. And secondly, the electric charge per unit mass of corpuscles was fantastically large. What kind of particles were these: unknown atoms carrying huge electrical charges, or tiny particles with negligible mass, but with a smaller charge? Further, he discovered that the ratio of specific charge to unit mass is a constant value, independent of the particle velocity, or of the cathode material, or of the nature of the gas in which the discharge occurs. Such independence was alarming. It seems that corpuscles were some kind of universal particles of matter, constituent parts of atoms. “After a long discussion of experiments,” Thompson writes in his memoirs, “it turned out that I could not avoid the following conclusions: 1. That atoms are not indivisible, since negatively charged particles can be pulled out of them under the influence of electrical forces, the impact of fast moving particles, ultraviolet light or heat. 2. That these particles are all of the same mass, carry the same charge of negative electricity, from whatever kind of atoms they come from, and are components of all atoms. 3. The mass of these particles is less than one thousandth of the mass of a hydrogen atom. I first called these particles corpuscles, but they are now called by the more appropriate name "electron". Thomson set to work. First of all, it was necessary to determine the parameters of the mysterious corpuscles, and then, perhaps, it would be possible to decide what they were. The results of the calculations showed: there is no doubt, unknown particles are nothing but the smallest electric charges - indivisible atoms of electricity, or electrons. On April 29, 1897, in the room where the meetings of the Royal Society of London had been held for more than two hundred years, his report was held. The listeners were delighted. The delight of those present was not at all due to the fact that colleague J. J. Thomson had so convincingly revealed the true nature of cathode rays. The matter was much more serious. Atoms, the first building blocks of matter, ceased to be elementary round grains, impenetrable and indivisible, particles without any internal structure... from something charged with positive electricity and from negatively charged corpuscles - electrons. Now the further, most necessary directions of future searches have become visible. First of all, of course, it was necessary to determine exactly the charge and mass of one electron. This would make it possible to clarify the masses of atoms of all elements, calculate the masses of molecules, and give recommendations for the correct preparation of reactions. In 1903, in the same Cavendish laboratory at Thomson's, G. Wilson made an important change to Thomson's method. In a vessel in which a rapid adiabatic expansion of the ionized air is carried out, capacitor plates are placed, between which it is possible to create an electric field and observe the fall of the cloud, both in the presence of a field and in its absence. Wilson's measurements gave a value for the charge of an electron as 3,1 times 10 to the minus tenth power of abs. email units Wilson's method was used by many researchers, including the students of St. Petersburg University Malikov and Alekseev, who found the charge equal to 4,5 times 10 to the minus tenth power of abs. email units This was the closest result to the true value obtained before Millikan began measuring with individual drops in 1909. So the electron was discovered and measured - a universal particle of atoms, the first of the so-called "elementary particles" discovered by physicists. This discovery made it possible for physicists, first of all, to raise the question of studying the electrical, magnetic and optical properties of matter in a new way. Author: Samin D.K.
▪ Chromosomal theory of heredity
Artificial leather for touch emulation
15.04.2024 Petgugu Global cat litter
15.04.2024 The attractiveness of caring men
14.04.2024
▪ Diamond nanowires are more efficient than Li-Ion batteries ▪ Toshiba Wireless Hard Drive Solution ▪ Space debris sensor to be installed on ISS ▪ DRAM production using EUV lithography
▪ section of the site Videotechnique. Article selection ▪ article What is allowed to Jupiter is not allowed to the bull. Popular expression ▪ What do bananas grow on? Detailed answer ▪ Wasabi article. Legends, cultivation, methods of application
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