Antoine Becquerel in his laboratory, c 1890s.
© Science Museum / Science & Society Picture Library
French physicist Antoine Becquerel (1852-1908) discovered that uranium salt placed on a wrapped photographic plate caused it to blacken even without light. Although this discovery was similar to W K Roentgen's (1845-1923) X-rays, it was not the same and led to Becquerel being awarded the Nobel Prize in 1903. He was also, indirectly, the father of radiotherapy as a cancer treatment, since he noticed that radium carried in his pocket produced a burn.