History

In 1985 the German physicist W.K. Roentgen studied electrical discharges in gases and discovered the existence of a very penetrating radiation was invisible able to ionize thegas, causing fluorescence in him, what he called X-ray
Subsequently, a French physicist, A.H. Becquerel wrapped photographic plates kept ina dark in the same drawer where he had a piece of uranium. His surprise was that the photographic plates was found this evening and found that what happened was that theuranium emitted radiation much more penetrating than X-rays He had discoveredradioactivity. It was later discovered new radioactive elements such as thorium, polonium, and actinium radio.
Thus we can define the property radioactivity present certain substances (radioactive substances) of emitting radiation capable of penetrating opaque and ionize the air.

Wilhelm Conrad Roentgen

W.K. Roentgen was born in 1845 to a wealthy merchant family in the small town ofLennep, in north-western Germany, after having spent most of childhood in the Netherlands, at the age of twenty years then moved to Zurich three years and graduatedin engineering from the Technische Hochschule close. Although there was often noexperimental physics course during their studies, decided to develop searches in thissector after the diploma. After receiving his doctorate in 1869, Roentgen won a series of assignments as a teacher at various German universities and executed in collaboration with Kundtattentive study of the behavior of matter, for example, was the first to demonstrate, with athermometer home made it easier to heat the moist air than dry air. Roentgen was when she turned quarantatré professor of physics and director of theInstitute of Physics, University of Wurzburg, a prosperous Bavarian town, the womanBertha lived in a spacious apartment on the second plan that included a study institutecommunicating with a private laboratory . In June 1894 he began studying cathode raysat that time very popular search argument and the night of November 8, 1895 during one of his experiments was the discovery of a type of rays of unknown nature that called"XES rays." Three weeks after Roentgen spread the news of his discovery: being able to seeobjects without breaking them and within the human body caused great sensation. Inconsequence of this he acquired a great reputation and in 1901 he was appointed the first Nobel Prize for physics

Antoine Henri Becquere

Antoine Henri Becquerel (born in Paris on December 15, 1852 - and died in Le Croisic, 25 August 1908, aged 55.) Físicofrancés was a discoverer of radioactivity and winning the Nobel Prize in Physics the year 1903.Son of Alexandre-Edmond Becquerel (who studied the light and the phosphorescence and invented fosforoscopia) and grandson of Antoine César Becquerel, a founder of electrochemistry.He studied and received his doctorate in Science at the Ecole Polytechnique in Paris.He was professor of Natural History Museum in 1892 (the third member of his family to do so) and the École Polytechnique in 1895. In 1894 he was appointed chief engineer of the French Ministry of Roads and Bridges. In its first activity in the field of scientific experiments investigated phenomena related to rotation of polarized light caused by the magnetic field. She later moved on to examine the spectrum resulting from the stimulation of phosphorescent crystals with infrared light.In 1896 accidentally discovered a new property of matter that was later called radioactivity. This phenomenon occurred during his research on phosphorescence. By placing uranium salts on a photographic plate in a dark area, found that the plate was blackened. Uranium salts emit radiation that penetrates black paper and other substances opaque to ordinary light. These rays are called Becquerel rays initially in honor of its discoverer. Also this character through their research and discoveries made valuable contributions to the atomic model.Following the discovery in late 1895, X-rays by Wilhelm Röntgen, Becquerel noted that they, on impact with a cathode ray beam in a glass tube which has a vacuum, they became fluorescent. Following this observation, we set out to identify whether there was a fundamental relationship between X-rays and visible radiation, so that all materials capable of emitting light, stimulated by any means, issue, also, X-rayTo test this hypothesis, crystals placed on a photographic plate wrapped in opaque paper so that only the invisible radiation, for X-rays could reveal the emulsion contained in the plate; previously crystals excited by exposure to sunlight . After a few hours found that the plate revealed the silhouette outlined by the glass.