The atom was an idea from antiquity. Democritus conceived of the idea, 2000 years ago, but it wasn't really picked up until the 18th century, with the birth of the steam age and the understanding that chemical reactions followed mass proportionality rules.
Atoms were a useful device to explain both the gas pressure in the steam engine and the combination rules of the chemical elements.
Yet, until the modern era, no one had ever seen an atom and a great debate raged about their existence, a debate which was not resolved until the start of the 20th century, when two giants of science, Albert Einstein and Ernest Rutherford, left us in no doubt.
And so the great revolution of 20th century science began, a revolution which has given us modern chemistry with its remarkable pharmaceuticals and new materials, and which has taken us deeper into the heart of matter to the realm of quarks; a revolution which explains the processes of life itself through molecular biology , and which has given us electronics and information technology, and the tools by which we may at last view atoms themselves.
This lecture will traverse historical themes surrounding the atom, as well as touching on the new challenges of the 21st century.
Professor Paul Callaghan, MacDiarmid Institute
Audio from EMC 2 Lecture Series on 13 Oct 2008