Born and raised in New Zealand, Ernest Rutherford (1871-1937) came to study at Cambridge University in England in 1895. Like the Curies, he wanted to learn how matter was put together. And as much as anyone, he succeeded. He showed that radioactivity was caused by the breakdown of one atom into another. He named the three forms of radiation produced by radioactivity alpha, beta, and gamma rays, and went on to prove that the alpha rays were actually the nuclei of helium atoms.

       Perhaps his biggest contribution to science, however, was his idea of the structure of the atom. By bombarding gold foil with alpha particles, he found that most of the particles passed through unaffected but a few bounced nearly straight back. From this, he deduced that atoms consist mostly of empty space with a heavy, positively charged nucleus at the center and a swarm of negatively charged electrons surrounding it. His idea, still accepted today, overthrew the notion of Democritus that the atom was without structure. After devising methods to locate submarines in World War I, he made his last great discovery. He used alpha particles to literally transform nitrogen atoms into oxygen, the first man-made transformation of one element into another. He had achieved the dream of the alchemists (though obviously not in the way they had imagined), but more importantly, had opened the door to the idea that elements could change.