Radioactivity was discovered by the French scientist Antoine Henri Becquerel in 1896 almost occasionally by conducting research on the fluorescence of double uranium and potassium sulfate. He discovered that uranium spontaneously emitted mysterious radiation.
After the discovery of X-rays pro Roentgen. Antoine Henri Becquerel began working with the theory that minerals were capable of emitting phosphorescent light. Phosphorescence is the ability of a crystal to absorb light and re-emit it later in the dark.
To verify his theory he carried out an experiment: wrap a photographic plate in black paper (to protect it from direct light), place a phosphorescent uranium mineral on it and expose it to bright sunlight. When it developed, the plate had a clear image of the uranium ore. Initially, he thought of this as a confirmation of his theory.
He experienced a month of February in Paris in which the sky was coincidentally cloudy. With the lack of solar radiation he could not continue his experiment, so he decided to keep the piece of uranium and the photographic plate wrapped in a drawer.
Accidental discovery of natural radioactivity
Days later he recovered the materials to resume the experiment. Becquerel expected the plaque to appear with a small amount of phosphorescence as a result of phosphorescence that had not yet faded. However, Bequerel found that the printed image was as intense as in the original experiment with solar radiation.
The surprise was huge and allowed Becquerel to reach the correct conclusion that this had nothing to do with the light. Instead, the exposure came from uranium itself, even in the dark.
Radioactivity had been discovered. He continued to demonstrate that uranium minerals were the only phosphorescent minerals that showed this effect.
These studies and analyzes were continued and perfected by the husbands Pierre and Marie Curie, who discovered two elements much more radioactive than the uranium they named Radio and Polonio, the latter in honor of Marie's homeland.
Beginnings of nuclear medicine
In a way, it can be said that Becquerel was also the father of the beginnings of research on nuclear medicine.
In 1901, Antoine Henri Bequerel experienced a skin burn as a result of carrying a piece of uranium in his pocket for a while. This event led him to be interested in the possible utility of nuclear radiation to treat cancerous tumors. From this point the technique continued to evolve until the well-known techniques of nuclear medicine such as chemotherapy or radiotherapy.
How did Becquerel die?
Evidently at the time when the radioactivity had just been discovered, nothing was known about the damage that nuclear energy could cause to health.
It is believed that this kind of pollution also broke Marie Curie's health.