Harriet Brooks was born on New Year's Day 1876, and became one the pioneer workers in the new science of radioactivity, a science that had begun in 1896 with the discovery of radioactivity in uranium.

She studied at university in Montreal, and went on to become a research worker for Ernest Rutherford, the father of nuclear physics and a man who was ahead of his time in his support for women working in science. In 1903 she arrived in England, and became the first woman to study at the famous Cavendish Laboratory in Cambridge. She spent 1906 and 1907 in Paris working with the legendary Marie Curie, before returning to her native Canada and working with Rutherford once more.

Brooks studied the 'emanations' from the radioactive element radium (whose discovery had been announced in 1898) and other radioactive elements. At the time it wasn't known what these emanations were. She concluded that the emanation was a gas, and reckoned that its atoms were a little smaller than those of its radium 'parent'. The gas eventually came to be called radon.

Later on, she showed that radon in turn could change (or transmute) into other elements. This changing of one element into another was alchemy made real, though without the end product of gold atoms so desired by traditional would-be alchemists.

It's now known that radioactive elements form decay chains where atoms of one element break down and form progressively lighter atoms - atoms of different elements. Rutherford and Brooks jointly published some of the landmark discoveries about radioactivity. In particular, Brooks' studies of the recoil of particles undergoing radioactive decay helped nuclear scientists to keep tabs on what was happening and what it was happening with.

Brooks went on to teach physics at a women's college but was obliged under the rules of the time to resign her post when she got married. Unsurprisingly, it wasn't a situation she was happy with, and despite high level negotiations and a postponement of the marriage her intended science career was cut short. Because she stepped down from science following her marriage, her contribution to science isn't as well known as it could be, but in a relatively short time she certainly made her mark on the fledgling science of radioactivity.

Sadly the health risks of the career were little understood at the time. She died at 56, probably due to leukaemia caused by her exposure to radiation.