The Discovery of Radium

In 1896, Antoine Bacquerrel learnt the fluorescence shown by uranic salts such as potassium uranyl sulphate made an interesting observation that a wrapped photographic plate was being affected by these salts even in the dark. It appeared therefore, that a new type of radiation was being emitted. The radiation passed through a black paper and affected a photographic plate.

Interested in the discovery Marie Curie suggested that the reason for the phenomenon was in the uranium atom as the other elements by themselves in uranium salts never emitted any rays.

Marie Curie began to test all sorts of substances for “rays” and soon discovered that thorium compounds were also active.

It was found that this radioactivity is an atomic property with an intensity directly proportional to the concentration of the element emitting it and independent of the state of chemical combination of that element.

Marie Curie noticed that certain ores showed greater activity than corresponded to their uranium content, and soon found that this was due to the presence of an unknown element, much more active than uranium. It was radium.

While separating radium salts from uranium ores the second radioactive element was discovered by Pierre and Marie Currie. They called it polonium, in honour of Poland, Marie Curie’s Motherland.

Notes on the text:

wrap –обертывать, завертывать.

emit – испускать, излучать.

correspond – соответствовать

affect smth. – влиять, воздействовать на ч.-л.

15. Read and retell the text using the underlined word-combinations: