Significance of isolation of radium? This is an extension of my previous question here.
Marie Curie isolated radium in 1903, which paved the way for the development of the theory of radioactivity. In regards to the techniques she used however, what was the impact of the establishment of those techniques? Were the techniques used by Curie new? Are they used today? What impact did they have on modern physics?
I can find a lot of information online about the actual isolation of radium, but not regarding the significance of the techniques used.
 A: It was Henri Becquerel who discovered radioactivity. Ernest Rutherford proved that what was happening was the disintegration and transmutation of atoms.
Radioactivity was discovered in Uranium, but the Curies discovered a mineral that was more radiocative.  They correctly deduced that it must contain a new element.  They then used purely chemical methods to separate the various elements, keeping track of which residuum had kept the radioactivity.  It's not my area, but I think that all of the methods were standard apart from using the radioactivity to trace.  And there was an enormous amount of work to be done.
They actually found two new elements, radium and polonium.  In a sense they were lucky, because they could have been chasing a radioactive isotope of a known element.  Isotopes were only recognised later.
A: The significance was that radium was many orders of magnitude more intense as a source of alpha particles than the previously available sources, such as uranium salts. For example, the Rutherford-Marsden discovery of the atomic nucleus would have been impossible without radium. That experiment used human eyeballs as detectors, and human eyeballs are not sensitive enough to have allowed the experiment to be done with weaker sources.
