How did radioactive discoveries begin?

Discovery of x rays

In 1895, W.C. X-rays found that the cathode-ray tube produced a highly penetrating radiation that could blacken portrait film, even if it was wrapped in black paper.

Because they don't know their essence, these rays are called X rays. It turns out that X rays are electromagnetic radiation that occurs due to high-speed collisions (ie cathode rays with a material (anode).

Now X rays are also called x-rays and are used for x-rays, namely to determine the state of the internal organs of the body.

Discovery of radioactive substance uranium rock

The discovery of X rays made Henry Becguerel interested in researching fluorescent substances, namely substances that can glow after first being exposed to radiation (irradiated), Becquerel suspected that the rays emitted by such substances were like X rays.

By chance, Becquerel researched uranium rocks. It turned out that the suspicion was correct that the light emitted by uranium could blacken the portrait film that was still wrapped in black paper. However, Becqueret found that uranium rock emits high penetrating light by itself without having to be exposed to it first.

This discovery occurred in early March 1986. Such a phenomenon, namely the spontaneous emission of radiation, is called radioactivity, and substances that are radioactive are called radioactive substances.

Discovery of Polonium and and Radium

The first radioactive substance discovered was uranium. In 1898, Marie Curie and her husband Pierre Curie discovered two other elements of uranium rock that were much more active than uranium.

The two elements they named respectively polonium (after the name Polonia, the country of origin of Marie Curie), and radium (derived from the Latin word radiare which means to shine).

In fact, many elements are naturally radioactive. All isotopes with atomic numbers above 83 are radioactive.

Elements with atomic number 83 or less have stable isotopes except technetium and promesium. Isotopes that are radioactive are called radioactive isotopes or radio-isotopes, while those that are not radiactive are called stable isotopes.

Today, radioisotopes can also be made from stable isotopes. So in addition to natural radioisotopes there are also artificial radioisotopes.