Labels:hakham | web site OCR: DISCOVERY OF RADIOACTIVITY 1896 BECOUEREI was looking for evidence that rays were emitted by chemicals that fluoresced in natural light. He took sample of potassium sulfate 0 uran ium and wrapped in black paper with a photographic plate. Beca use was a dull day and the sample was not fluorescing, he put it away in drawer in his laboratory and continued with his experiments with cathode ray tubes. A few days later he punoj that the sample had produced an image on the photographic plate: had been emitting form radiation which Marie Curie later named radioactivity. BECQUEREL found