The phenomenon of radioactivity scientist. Who discovered the phenomenon of radioactivity and how did it happen? Natural radioactivity: levels, doses, risks
The article tells about who discovered the phenomenon of radioactivity, when it happened and under what circumstances.
Radioactivity
The modern world and industry are unlikely to be able to do without nuclear energy. Nuclear reactors power submarines, provide electricity to entire cities, and special energy sources based on are installed on artificial satellites and robots that study other planets.
Radioactivity was discovered at the very end of the 19th century. However, like many other important discoveries in various fields of science. But which of the scientists first discovered the phenomenon of radioactivity and how did this happen? We will talk about this in this article.
Opening
This very important event for science took place in 1896 and was made by A. Becquerel while studying the possible connection between luminescence and the recently discovered so-called x-rays.
According to the memoirs of Becquerel himself, he came up with the idea that, perhaps, any luminescence is also accompanied by X-rays? In order to test his guess, he used several chemical compounds, including one of the uranium salts, which glowed in the dark. Then, holding it under the sun's rays, the scientist wrapped the salt in dark paper and put it in a closet on a photographic plate, which, in turn, was also packed in an opaque wrapper. Later, having shown it, Becquerel replaced the exact image of a piece of salt. But since the luminescence could not overcome the paper, it means that it was X-ray radiation that illuminated the plate. So now we know who first discovered the phenomenon of radioactivity. True, the scientist himself did not yet fully understand what discovery he had made. But first things first.
Meeting of the Academy of Sciences
A little later in the same year, at one of the meetings at the Academy of Sciences of Paris, Becquerel made a report "On the radiation produced by phosphorescence." But after some time, adjustments had to be made to his theory and conclusions. So, during one of the experiments, without waiting for good and sunny weather, the scientist put a uranium compound on a photographic plate, which was not irradiated with light. Nevertheless, its clear structure was still reflected on the disc.
On March 2 of the same year, Becquerel presented a new work to the meeting of the Academy of Sciences, which described the radiation emitted by phosphorescent bodies. Now we know which of the scientists discovered the phenomenon of radioactivity.
Further experiments
Being engaged in further studies of the phenomenon of radioactivity, Becquerel tried many substances, including metallic uranium. And each time, traces invariably remained on the photographic plate. And by placing a metal cross between the radiation source and the plate, the scientist obtained, as they would say now, his x-ray. So we sorted out the question of who discovered the phenomenon of radioactivity.
It was then that it became clear that Becquerel discovered a completely new type of invisible rays that are able to pass through any objects, but at the same time they were not X-rays.
It was also found that the intensity depends on the amount of uranium itself in chemical preparations, and not on their types. It was Becquerel who shared his scientific achievements and theories with the spouses Pierre and Marie Curie, who subsequently established the radioactivity emitted by thorium and discovered two completely new elements, later called polonium and radium. And when analyzing the question “who discovered the phenomenon of radioactivity,” many often mistakenly attribute this merit to the Curies.
Impact on living organisms
When it became known that all uranium compounds emit, Becquerel gradually returned to the study of the phosphor. But he managed to make one more important discovery - the effect of radioactive rays on biological organisms. So Becquerel was not only the first to discover the phenomenon of radioactivity, but also the one who established its effect on living beings.
For one of the lectures, he borrowed a radioactive substance from the Curies and put it in his pocket. After the lecture, returning it to its owners, the scientist noticed a strong reddening of the skin, which had the shape of a test tube. after listening to his guesses, he decided on an experiment - for ten hours he wore a test tube containing radium tied to his arm. As a result, he received a severe ulcer that did not heal for several months.
So we sorted out the question of which of the scientists first discovered the phenomenon of radioactivity. This is how the influence of radioactivity on biological organisms was discovered. But despite this, the Curies, by the way, continued to study radiation materials, and died precisely from radiation sickness. Her personal belongings are still kept in a special lead-lined vault, since the dose of radiation accumulated by them almost a hundred years ago is still too dangerous.
Who discovered radioactivity and made such a significant discovery in science, you will learn from this article.
Who discovered radioactivity?
The mainstream science is that spouses and discovered radioactivity. But this phenomenon in front of the spouses was accidentally discovered by several scientists earlier.
The first phenomenon of radioactivity opened by photographer Abel Niepce de Saint-Victor, moreover, quite by accident in 1857, when he made an attempt to get color photographs. While experimenting with metal salts, he discovered that some salts leave prints on photographic paper in the dark. They were uranium salts, which served as an invisible source of radiation of radioactivity. But it was considered dangerous to humans, so for a while they forgot about it.
French physicist Antoine Becquerel studied phosphorescent minerals, which glow for a while after exposure to the sun. Prior to that, he studied X-rays and believed that they were related. In order to test this assumption, Becquerel experimented with uranium salts, which confirmed his hypothesis. So he discovered radioactivity in 1896.
However the term "radioactivity" was invented and introduced into scientific circulation not by him at all, but by Marie Sklodowska-Curie. She, together with her husband Pierre, was engaged in the study of this phenomenon.
Education
Who discovered the phenomenon of radioactivity and how did it happen?
June 16, 2016The article tells about who discovered the phenomenon of radioactivity, when it happened and under what circumstances.
Radioactivity
The modern world and industry are unlikely to be able to do without nuclear energy. Nuclear reactors power submarines, provide electricity to entire cities, and special energy sources based on radioactive decay are installed on artificial satellites and robots that study other planets.
Radioactivity was discovered at the very end of the 19th century. However, like many other important discoveries in various fields of science. But which of the scientists first discovered the phenomenon of radioactivity and how did this happen? We will talk about this in this article.
Opening
This very important event for science took place in 1896 and was made by A. Becquerel while studying the possible connection between luminescence and the recently discovered so-called x-rays.
According to the memoirs of Becquerel himself, he came up with the idea that, perhaps, any luminescence is also accompanied by X-rays? In order to test his guess, he used several chemical compounds, including one of the uranium salts, which glowed in the dark. Then, holding it under the sun's rays, the scientist wrapped the salt in dark paper and put it in a closet on a photographic plate, which, in turn, was also packed in an opaque wrapper. Later, having shown it, Becquerel replaced the exact image of a piece of salt. But since the luminescence could not overcome the paper, it means that it was X-ray radiation that illuminated the plate. So now we know who first discovered the phenomenon of radioactivity. True, the scientist himself did not yet fully understand what discovery he had made. But first things first.
Meeting of the Academy of Sciences
A little later in the same year, at one of the meetings at the Academy of Sciences of Paris, Becquerel made a report "On the radiation produced by phosphorescence." But after some time, adjustments had to be made to his theory and conclusions. So, during one of the experiments, without waiting for good and sunny weather, the scientist put a uranium compound on a photographic plate, which was not irradiated with light. Nevertheless, its clear structure was still reflected on the disc.
On March 2 of the same year, Becquerel presented a new work to the meeting of the Academy of Sciences, which described the radiation emitted by phosphorescent bodies. Now we know which of the scientists discovered the phenomenon of radioactivity.
Further experiments
Being engaged in further studies of the phenomenon of radioactivity, Becquerel tried many substances, including metallic uranium. And each time, traces invariably remained on the photographic plate. And by placing a metal cross between the radiation source and the plate, the scientist obtained, as they would say now, his x-ray. So we sorted out the question of who discovered the phenomenon of radioactivity.
It was then that it became clear that Becquerel discovered a completely new type of invisible rays that are able to pass through any objects, but at the same time they were not X-rays.
It was also found that the intensity of radioactive radiation depends on the amount of uranium itself in chemical preparations, and not on their types. It was Becquerel who shared his scientific achievements and theories with the spouses Pierre and Marie Curie, who subsequently established the radioactivity emitted by thorium and discovered two completely new elements, later called polonium and radium. And when analyzing the question “who discovered the phenomenon of radioactivity,” many often mistakenly attribute this merit to the Curies.
Impact on living organisms
When it became known that all compounds of uranium emit radioactive radiation, Becquerel gradually returned to the study of the phosphor. But he managed to make one more important discovery - the effect of radioactive rays on biological organisms. So Becquerel was not only the first to discover the phenomenon of radioactivity, but also the one who established its effect on living beings.
For one of the lectures, he borrowed a radioactive substance from the Curies and put it in his pocket. After the lecture, returning it to its owners, the scientist noticed a strong reddening of the skin, which had the shape of a test tube. Pierre Curie, after listening to his guesses, decided to experiment - for ten hours he wore a test tube containing radium tied to his arm. As a result, he received a severe ulcer that did not heal for several months.
So we sorted out the question of which of the scientists first discovered the phenomenon of radioactivity. This is how the influence of radioactivity on biological organisms was discovered. But despite this, the Curies, by the way, continued to study radiation materials, and Marie Curie died precisely from radiation sickness. Her personal belongings are still kept in a special lead-lined vault, since the dose of radiation accumulated by them almost a hundred years ago is still too dangerous.
The emergence of radiobiology is due to three great discoveries that crowned the end of the previous century:
1895 - discovery of X-rays by Wilhelm Conrad Roentgen;
1896 - Henri Becquerel's discovery of the natural radioactivity of uranium;
1898–discovery by the Curie couple, Maria Skłodowska and Pierre, of the radioactive properties of polonium and radium.
Wilhelm Conrad Roentgen was 50 years old at the time of his great discovery. He then directed the Physics Institute and the Department of Physics at the University of Würzburg. November 8, 1895 Roentgen, as usual, finished experiments in the laboratory late in the evening. Turning off the light in the room, he noticed in the darkness a greenish glow emanating from salt crystals scattered on the table. It turned out that he forgot to turn off the voltage on the cathode tube he was working with that day. The glow immediately stopped as soon as the current was turned off, and immediately appeared when it was turned on. Investigating a mysterious phenomenon, Roentgen came to a brilliant conclusion: when a current passes through a tube, some unknown radiation appears in it. It is this that causes the crystals to glow. Not knowing the nature of this radiation, he called it X-rays.
The resulting hype and fables could not weaken the interest in the great discovery. X-rays immediately became not only the subject of deep study throughout the world, but also quickly found practical applications. In addition, they served as a direct impetus to the discovery of a new phenomenon - natural radioactivity, which shocked the world less than six months after the discovery of X-rays.
X-rays not only immediately became the subject of deep study throughout the world, but also quickly found practical applications. In addition, they served as an impetus for the discovery of a new phenomenon - natural radioactivity, which shocked the world less than six months after the discovery of X-rays. One of those who was interested in the nature of "all-penetrating" X-rays was Henri Becquerel, professor of physics at the Paris Museum of Natural History. Having once developed a photographic plate wrapped in black paper left on the table, Becquerel discovered that it was illuminated only in the place where the uranium salt was poured. Repeating observations several times in sunny and cloudy weather, the scientist came to the conclusion that uranium arbitrarily, regardless of solar radiation, emits “uranium rays” invisible to the eye.
Dozens of researchers after the discovery of Roentgen were looking for new mysterious radiations. But only the inquisitive and talented A. Becquerel managed to distinguish spontaneous emission of penetrating radiation by uranium from luminescence induced by sunlight.
Dozens of researchers after the discovery of Roentgen were busy searching for new mysterious radiations. The study of this phenomenon became the subject of a passionate search for the great Polish scientist Marie Sklodowska-Curie, and soon her husband, no less brilliant French researcher Pierre Curie.
On July 18, 1898, the Curies announced the discovery of a new radioactive element - polonium named after the homeland of M. Curie - Poland, and on December 26 M. Curie and J. Bemont - about the discovery of the second radioactive element - radium.Work on the study of radioactivity continued to develop rapidly. In 1899, M. Curie discovered that the air around radium compounds becomes a conductor of electric current, and in 1900, the German chemist E. Dorn reported the discovery of a new gaseous radioactive element released from radium preparations. He named this element radon. . In the same year in England, E. Rutherford and R. Owen found that thorium emits a radioactive gas, which they called emanation (thoron). radioactive gas is also released. In the same year, Canadian J. McLennon found that stable radium-G (RaG) is formed as a result of radioactive transformations of radium, and O. Hahn and L. Meitner found the end product of thorium transformation - stable thorium-D (ThD).
In 1900, the English scientist V. Crooks and independently of him
BUT.
In 1911, K. Fajans determined that the radioactive transformation of RaC proceeds in two ways: with the formation of radium-C / (RaC) and radium-C "(RaC"). In the same year, the Russian scientist G.N.
Antonov in Rutherford's laboratory found from the UX decay curve that it contains a radioactive impurity - an element that he called ypan-Y (UY). In 1913, F. Soddy and the German scientist O. Goering discovered in the decay products of uranium uranium-X 2 (UX 2), called brium, and the British E. Marsden and R. Wilson discovered the duality of the decay of thorium-C into thorium-C "( ThC") and thorium-D (ThD). G. McCoy and S. Viol in the USA investigated the chemical properties of radioactive elements - products of the decay of thorium. Next, O. Gan andL. Meitner and, independently of them, F. Soddy and J. Cranston isolated from uranium ores a new radioactive element, protactinium (Ra), a precursor of actinium.
The number of newly discovered radioactive elements catastrophically increased, which contradicted the periodic table of elements
DI. Mendeleev. Most of them had no place in this system. At the same time, as we have seen, information was accumulating about the transformations of some radioactive elements into others, about their interrelationships. All these discoveries of new elements were carried out along the beaten track by M. Curie - by the method of carriers.
On March 1, 1896, the French physicist A. Bakkrel discovered, by blackening a photographic plate, the emission of invisible rays of strong penetrating power from uranium salt. He soon found out that uranium itself also has the property of radiation. Then he discovered such a property in thorium.
Radioactivity (from the Latin radio - I radiate, radus - a beam and activus - effective), this name was given to an open phenomenon, which turned out to be the privilege of the heaviest elements of the periodic system of D.I. Mendeleev.
There are several definitions of this remarkable phenomenon, one of which gives it the following formulation: “Radioactivity is a spontaneous
(spontaneous) transformation of an unstable isotope of a chemical element into another isotope (usually an isotope of another element); in this case, electrons, protons, neutrons, or helium nuclei (α-particles) are emitted”
The essence of the discovered phenomenon was the spontaneous change in the composition of the atomic nucleus, which is in the ground state or in an excited long-lived state.
In 1898, other French scientists Maria Sklodowska-Curie and Pierre
The Curies isolated two new substances from the uranium mineral, radioactive to a much greater extent than uranium and thorium. Thus, two previously unknown radioactive elements were discovered - polonium and radium, and Maria, in addition, discovers (regardless of the German physicist G. Schmidt) the phenomenon of radioactivity in thorium. By the way, she was the first to propose the term radioactivity. Scientists came to the conclusion that radioactivity is a spontaneous process that occurs in the atoms of radioactive elements. Now this phenomenon is defined as the spontaneous transformation of an unstable isotope of one chemical element into an isotope of another element, and in this case, electrons, protons, neutrons, or helium nuclei are emitted? - particles. It should be noted here that among the elements contained in the earth's crust, all with serial numbers over 83 are radioactive, i.e. located in the periodic table after bismuth. For 10 years of joint work, they have done a lot to study the phenomenon of radioactivity. It was selfless work in the name of science - in a poorly equipped laboratory and in the absence of the necessary funds. Pierre established the spontaneous release of heat by radium salts. Researchers received this preparation of radium in 1902 in the amount of 0.1 g. To do this, they took 45 months of hard work there and more than 10,000 chemical liberation and crystallization operations. In 1903, the Nobel Prize in Physics was awarded to the Curies and A. Beckerey for their discovery in the field of radioactivity. In total, more than 10 Nobel Prizes in physics and chemistry were awarded for work related to the study and use of radioactivity (A. Beckerey, P. and M. Curie, E. Fermi, E. Rutherford, F. and I. Joliot-Curie,
D.Havishi, O.Ganu, E.McMillan and G.Seaborg, W.Libby and others). In honor of the spouses
Curie got its name from an artificially obtained transuranium element with serial number 96 - curium.
In 1898, the English scientist E. Rutherford began to study the phenomenon of radioactivity. In 1903, E. Rutherford proves the error of the assumption of the English physicist D. Thompson about his theory of the structure of the atom and in
1908-1911 conducting scattering experiments? - particles (helium nuclei) with metal foil. ? – the particle passed through a thin foil (thick
1 μm) and, falling on a screen of zinc sulfide, generated a flash, which was well observed under a microscope. Scattering experiments? - particles convincingly showed that almost the entire mass of an atom is concentrated in a very small volume - the atomic nucleus, the diameter of which is about 100,000 times smaller than the diameter of the atom.
Majority? - particles fly past the massive nucleus without hitting it, but occasionally there is a collision? are particles with a nucleus, and then it can bounce back. Thus, his first fundamental discovery in this area was the discovery of the inhomogeneity of the radiation emitted by uranium. So for the first time the concept of? - and? - rays. He also suggested names: ? - disintegration and - particle. A little later, another component of the radiation was discovered, designated by the third letter of the Greek alphabet: ?-rays. This happened shortly after the discovery of radioactivity. For many years? – particles have become for E. Rutherford an indispensable tool for the study of atomic nuclei. In 1903, he discovers a new radioactive element - the emanation of thorium. In 1901-1903, together with the English scientist F. Soddy, he conducted research that led to the discovery of the natural transformation of elements (for example, radium into radon) and the development of a theory of radioactive decay of atoms.
In 1903, the German physicist K. Fajans and F. Soddy independently formulated a displacement rule that characterizes the movement of an isotope in the periodic system of elements during various radioactive transformations.
In the spring of 1934, an article entitled "A New Type of Radioactivity" appeared in the Reports of the Paris Academy of Sciences. Its authors Irene Joliot-Curie and her husband Frédéric Joliot-Curie found that boron, magnesium, and aluminum were irradiated? - particles, become themselves radioactive and emit positrons during their decay. This is how artificial radioactivity was discovered. As a result of nuclear reactions (for example, when various elements are irradiated with particles or neutrons), radioactive isotopes of elements are formed that do not exist in nature. It is these artificial radioactive products that make up the vast majority of all currently known isotopes. In many cases, the products of radioactive decay themselves turn out to be radioactive, and then the formation of a stable isotope is preceded by a chain of several acts of radioactive decay. Examples of such chains are the series of periodic isotopes of heavy elements, which begin with 238U, 235U, 232 nucleides and end with stable lead isotopes 206Pb, 207Pb, 208Pb. So, out of the total number of about 2000 radioactive isotopes known today, about 300 are natural, and the rest are obtained artificially, as a result of nuclear reactions. There is no fundamental difference between artificial and natural radiation. In 1934 I. and F.
Joliot-Curie, as a result of the study of artificial radiation, new variants of ?-decay were discovered - the emission of positrons, which were originally predicted by Japanese scientists H. Yukkawa and S. Sakata. I. and F. Joliot-Curie carried out a nuclear reaction, the product of which was a radioactive isotope of phosphorus with a mass number of 30. It turned out that he emitted a positron. This type of radioactive transformation is called?+ decay (meaning by?-decay the emission of an electron).
One of the outstanding scientists of our time, E. Fermi, devoted his main works to research related to artificial radioactivity.
The theory of beta decay created by him in 1934 is still used by physicists to understand the world of elementary particles.
Theorists have long predicted the possibility of a double? - transformation into 2? - decay, in which two electrons or two positrons are simultaneously emitted, but in practice this way of "death" of a radioactive nucleus has not yet been discovered. But relatively recently it was possible to observe a very rare phenomenon of proton radioactivity - the emission of a proton from the nucleus, and the existence of two-proton radioactivity, predicted by the scientist, was proved.
V.I. Goldansky. All these types of radioactive transformations are confirmed only by artificial radioisotopes, and they do not occur in nature.
Subsequently, a number of scientists from different countries (J.Duning,
V.A.Karnaukhov, G.N.Flerov, I.V.Kurchatov and others) discovered complex transformations, including ?-decay, including the emission of delayed neutrons.
One of the first scientists in the former USSR who started studying the physics of atomic nuclei in general and radioactivity in particular was
I.V.Kurchatov. In 1934, he discovered the phenomenon of branching of nuclear reactions caused by neutron bombardment and investigated artificial radioactivity. a number of chemical elements. In 1935, when bromine was irradiated with neutron fluxes, Kurchatov and his collaborators noticed that the radioactive bromine atoms arising in this process decay at two different rates.
Such atoms were called isomers, and the phenomenon discovered by scientists isomerism.
Science has established that fast neutrons are capable of destroying uranium nuclei. In this case, a lot of energy is released and new neutrons are formed, capable of continuing the process of fission of uranium nuclei. Later it was discovered that the atomic nuclei of uranium can be divided without the help of neutrons. So spontaneous (spontaneous) fission of uranium was established. In honor of the outstanding scientist in the field of nuclear physics and radioactivity, the 104th element of the periodic system of Mendeleev is named kurchatovium.
The discovery of radioactivity had a huge impact on the development of science and technology. It marked the beginning of an era of intensive study of the properties and structure of substances. The new prospects that arose in energy, industry, the military field of medicine and other areas of human activity due to the mastery of nuclear energy were brought to life by the discovery of the ability of chemical elements to spontaneous transformations. However, along with the positive factors of using the properties of radioactivity in the interests of mankind, examples of their negative interference in our lives can also be given. These include nuclear weapons in all its forms, sunken ships and submarines with nuclear engines and nuclear weapons, disposal of radioactive waste in the sea and on land, accidents at nuclear power plants, etc. and directly for Ukraine, the use of radioactivity in nuclear energy has led to
Chernobyl tragedy.
ESSAY
on the topic: OPENING
RADIOACTIVITY
made up:
E. Rubansky