Harriet Brooks

Harriet Brooks was a pioneering nuclear physicist who became Ernest Rutherford's first graduate student at McGill University in 1898. Working on thorium decay, Brooks made the critical experimental discovery that thorium emitted a radioactive gas rather than particles, identifying what Rutherford named "emanation," later recognized as the element radon.

Brooks was also the first scientist to observe the phenomenon of atomic recoil during radioactive disintegration. She conducted advanced research at the Cavendish Laboratory in Cambridge and with Marie Curie at the Institut du Radium in Paris, earning Rutherford's praise as the most gifted female physicist after Madame Curie.