How Were Isotopes Discovered?

In 1913, an English Radiochemist named Frederick Soddy announced that, through his work on radioactive decay chains, and far-too-many elements that seem to exist between Uranium and Lead on the periodic table, he had found evidence of isotopes-versions of elements that have the same chemical properties but different masses. In this video, I researched his story, which often goes untold in chemistry textbooks, and tried to summarize it. I hope you enjoy it, as well as the tidbit about where the term "isotope" came from!