What is the evidence of the phenomenon of radioactivity? Radioactivity: the discovery of Becquerel. The phenomenon of radioactivity: the experience of Rutherford

At the end of 1895, for the first time in the press, sensational information appeared about the discovery of a new type of radiation by Conrad Röntgen. These rays, which the scientist called X-rays, easily passed through various materials - wood, cardboard and other objects that had an opaque texture for sunlight. The discovery of these rays has greatly agitated the scientific world. And maybe, for this reason, the world did not immediately notice yet another revolution in physics - in 1896 Henri Becquerel discovered a new phenomenon, namely, radioactivity.

Radioactivity. Discovery of Becquerel

In the future, for his discoveries, Antoine Henri Becquerel, along with the Curie couple, will receive the Nobel Prize. After all, these scientists, according to the Nobel Committee, discovered spontaneous radioactive radiation. In his youth, Henri received the best education and worked as an assistant to Alexander Becquerel, his father. The first scientific publications of Henri Becquerel concerned the study of the temperature of the Earth's surface. The discovery of radioactivity by Antoine Becquerel occurred much later. Prior to this, the scientist was engaged in the study of luminescence, the phenomenon of the polarization of light, the absorption of light by crystals. The last of the regions brought Becquerel a doctorate in physics. Subsequently, Becquerel found that part of the radiation is some rays, which by their very nature are very similar to X-rays. He found out that if uranium is used in experiments, then the radiation turns out to be more powerful.

The history of the discovery of the phenomenon of radioactivity: further research

Maria Curie was also Becquerel's apprentice. She discovered that the phenomenon of radioactivity has another substance - thorium. At that time no one knew yet what the phenomenon of radioactivity testifies to. At a meeting of members of the French Academy of Sciences, Becquerel announced his amazing discovery.

He told the scientists that those rays that were open to him can spontaneously penetrate through any surface. In their properties they were similar to X-ray. Spontaneously, without any activity, this radiation came from some substances. The scientist has established, that it is peculiar to substances in which structure uranium joins. And Becquerel called this type of radiation uranium.

What is the evidence of the phenomenon of radioactivity?

The discovery of the phenomenon of radioactivity passed almost in the shadow of research by other scientists. But later these rays were called radioactive radiation. It was found out that not only uranium can emit radiation of this kind, this property is inherent in other substances. In fact, this discovery was one of the most epoch-making in physics, because the phenomenon of radioactivity discovered by Becquerel shows that the nucleus of an atom has a very complex structure.

It is interesting that for the phenomenon, which was discovered by him completely by accident, the scientist was awarded the same Nobel Prize, which the Curie couple received for a long titanic work. But these scientists were awarded equal marks. Unfortunately for all, this kind of work for scientists did not pass without a trace. In 1906 Pierre Curie died , and Becquerel survived him only for two years, having passed away at the age of 57 years.

Scientific revolution in physics

The question, as evidenced by the phenomenon of radioactivity, remained open for a long time. The study of this puzzle was continued by the world-famous couple of chemists - Maria Sklodowska and Pierre Curie. They carefully studied the new phenomenon. The very name "radioactivity" was suggested by Maria Curie-Sklodowska.

For many scientists, as a result of the research, the previous picture of the world turned out to be completely untenable. After all, before that it was believed that the atom is a single and indivisible particle of being. What is the evidence of the phenomenon of radioactivity in fact? First of all, it testifies to the fallacy of the theory of indivisibility of atoms. This view existed since the time of the ancient Greek scholars. After all, the very name "atom" is translated from ancient Greek as "indivisible." So, radioactivity as evidence of the complex structure of the atomic nucleus suggests that the atom has a very complex structure. When decaying into new elements, it emits radiation of various types: alpha, beta, and gamma radiation.

Rutherford's interest in the problem of radioactivity

One of the greatest contributions to knowledge of radioactivity was made by scientist Ernest Rutherford. He was born in 1871 in New Zealand in a farm family. In 1896, Rutherford became aware of the discovery of an English scientist. "The phenomenon of radioactivity discovered by Becquerel shows that the atom can be divided into parts," this postulate so interested young Rutherford that in 1899 his first work on uranium and its electrical conductivity appeared. This research was the beginning of Rutherford's study of nuclear transformations and the discovery of the atomic nucleus.

The beginning of the study of the atom from within

In 1911, Rutherford made one of the most outstanding discoveries, which glorified him throughout the world. Scientists discovered the atomic nucleus. Rutherford made the assumption that the atom can contain a positively charged core, and it is surrounded by particles of the opposite charge. Rutherford calculated the approximate deflection of a particle that flew past the atom. A new model of the scientist was perceived by the scientific community skeptically. However, it was she who became the basis for the modern theory of the structure of the atom.

Final confirmation of Rutherford's hypothesis

The scientist carefully studied radioactivity as a physical phenomenon. As a result, he investigated the complex composition of the uranium structure and found very strongly absorbed rays. Their Rutherford called alpha rays. Also, scientists were discovered less absorbed rays, which he called beta rays.

In his works, the researcher continued to study the phenomenon of radioactivity studied in the works of the Curie spouses. The experience of Rutherford showed that radioactivity is an atomic phenomenon, which is accompanied by chemical changes in the substance itself. In his study, conducted in conjunction with the chemist Soddy, in 1903, Rutherford finally affirms his hypothesis. He formulates the law of radioactive decay, and also describes the chains of chemical transformations of substances such as uranium, radium and thorium.

What was Rutherford's experience?

The scientist put the experience of scattering alpha particles. Their bundle had to pass through a thin layer of gold foil. Rutherford chose gold for good reason: it was this material that was very flexible, and it was possible to get a layer of almost one atom thick. During the experiment, Rutherford received the following observations. Some alpha particles passed through the foil, forming on the screen blurred spots.

Others were only recorded on the side screens. The scientist's experience has shown that the positive charge inside the atom is mainly inside its nucleus, and that the nuclei of different atoms are separated by huge gaps. A phenomenon in which a chemical spontaneously emits particles that have a significant permeability is called the phenomenon of natural radioactivity. Now it became known, as evidenced by the phenomenon of radioactivity. It turned out that the nuclei of the atom are endowed with the ability to decay spontaneously.

Chain fission reaction of the nucleus

Rutherford also revealed some patterns of radioactive decay. For example, when heavy nuclei are divided, several free neutrons can occur. Thus, the chain reaction of fission, called by the scientist, can be organized. With it, the free neutrons, propagating in a medium containing heavy elements, provoke the appearance of new neutrons. If this medium is characterized by a high content of neutrons, then the process is avalanche-like. When the number of neutrons is insufficient, the chain reaction gradually decreases to zero. The device in which such nuclear reactions are maintained artificially is called a nuclear reactor.