Strange Rays From Radioactivity Was An Accidental Discovery
One day, Henri Becquerel studied the connection between X-rays and phosphorescence in the 1890s. He wanted to try and absorb X-ray energy from the sun and did this by wrapping photographic plates in black paper and exposing it to the sun using uranium salts. The weather was overcast, so he abandoned the idea for the day. But the unexposed plates had a mark, and it was clear the uranium salts were emitting rays, and they stained the plate, despite the paper in between. And that was the birth of radioactivity(Timeline).