Harry Rutherford and his colleagues Geiger and Marsden find that occasionally one of these alpha particles actually bounces back off these gold atoms. This then leads to the modern sort of cartoon model of the atom that we know about in schools, this sort of solar system light model. And what this really shows is that Thomson's warbly sponge like atom is not the right model.
Melvyn Bragg and guests discuss an atomic particle that's become inseparable from modernity. JJ Thomson discovered the electron 125 years ago, so revealing that atoms, supposedly the smallest things, were made of even smaller things. He pictured them inside an atomic ball like a plum pudding, with others later identifying their place outside the nucleus - and it is their location on the outer limit that has helped scientists learn so much about electrons and with electrons. We can use electrons to reveal the secrets of other particles and, while electricity exists whether we understand electrons or not, the applications of electricity and electrons grow as our knowledge grows. Many questions, though, remain unanswered.
With
Victoria Martin
Professor of Collider Physics at the University of Edinburgh
Harry Cliff
Research Fellow in Particle Physics at the University of Cambridge
And
Frank Close
Professor Emeritus of Theoretical Physics and Fellow Emeritus at Exeter College at the University of Oxford
Producer: Simon Tillotson