German physicist · 1848–1916
Friedrich Ernst Dorn
Friedrich Ernst Dorn discovered in 1900 that radium constantly gives off a radioactive gas, now known as radon.
How Radon was found
Ernest Rutherford and Robert Owens had noticed in 1899 that thorium released a radioactive “emanation”. Dorn found that radium compounds did the same, and that the gas carried its radioactivity with it when moved.
He called it radium emanation. Ramsay and Whytlaw-Gray later measured its density and showed it was the heaviest noble gas. It was named radon in 1923.
Life and career
Born 1848 · Died 1916
Dorn was born in Guttstadt, East Prussia, and studied at Königsberg. He became professor of physics at Halle, where he worked on electricity, X-rays and radioactivity.
Legacy
Radon seeping from the ground is today the main source of natural radiation exposure, and the second leading cause of lung cancer in many countries.
Discovered in the same era
Other elements identified within ten years of 1900.