Discovery of radioactivity.

History knows cases when great ideas came to scientists quite by accident. This can be attributed to the French physicist Henri Becquerel, who in 1896 carried out the discovery of radioactivity. The reason for the experiment was the study of V. X-ray X-rays. At the same time, the scientist assumed that they are associated with a phenomenon such as luminescence. And it is likely that this type of luminescence is impossible without cathode rays.

Becquerel decided to study the hypothesis put forward by V. Roentgen. He was interested in whether luminous substances could emit rays having the ability to penetrate through opaque septa. To answer this question, Becquerel took a photographic plate, wrapped it in a black film, placed a copper cross and covered it with salt from the top, and set it in the sun. After some time he showed a film. It turned out that it blackened in the places where the cross was. This indicated that uranium is capable of producing radiation passing through opaque objects and acting on a photographic plate. At that time A. Becquerel believed that the reason for the glow of uranium is the sun.

After some time, the scientist decided to repeat the experiment again. But this time the cloudy rainy weather prevented him from starting the research. Becquerel put the plate in a black wrapper with a cross in a dark closet for several days. When the physicist showed the film, it turned out that, being in the dark, it turned black much more than when exposed to the sun. Investigating a large number of chemical compounds, Becquerel has determined that only substances that contain uranium are able to emit rays penetrating through a dark paper. This was the discovery of radioactivity

Subsequently, this phenomenon was carefully studied by the spouses Maria Sklodowska and Pierre Curie. The discovery of radioactivity was the reason for studying many other elements. Pierre and Maria found that many chemicals can emit rays of three inputs: beta, alpha, gamma . They thoroughly studied the phenomenon of radioactivity, studied its penetrating power and behavior in a magnetic field. These discoveries allowed scientists to find the mass, velocity and charge of particles that make up the rays.

As a result of the research, significant discoveries were made in the field of physics. It turned out that the alpha rays consist of a huge number of relatively heavy particles, the speed of which is 16 thousand km per second. Each of them has two positive charges of electricity and has a mass. At the heart of beta rays are electrons, or negatively charged light elements. Their speed reaches more than 300 thousand km per second. And gamma rays are similar in composition to X-rays. A little later, physicists discovered several interesting facts. It turned out that by emitting beta or alpha particles, the atoms of certain chemical elements can be transformed into others.

As a result of the study of ores containing thorium and uranium, a completely new chemical element, previously unknown, was discovered. Its name - polonium - he received in honor of his native country of Mary - Poland. A little later, physicists discovered another radioactive element - radium (radiant). This component allocated fairly strong radiation. In the D. Mendeleyev table, radium, which has an atomic mass of 226, occupied 88 cells. A little later it was determined that the chemical elements, the serial number of which is more than 83, are by nature radioactive, that is, they are capable of generating radiation spontaneously.

In 1903, the Curie couple for the discovery of radioactivity were awarded the Nobel Prize. Maria Sklodovskaya becomes the first female professor in history. Thanks to her at the Sorbonne University for the first time introduced a course of lectures on the study of radioactivity.