100 Physics Ideas in 100 Words

g CONTENTS

Atomic Physics

The 20th century can be thought of as the century of the atom. Once Albert Einstein had explained Brownian motion no scientist could reject the idea that matter was made of atoms. Then the nucleus of the atoms was discovered by Ernest Rutherford and his colleagues. The structure of the atom was explained in terms of subatomic particles – protons, neutrons and electrons.

The forces within the nucleus explain radioactivity, fission and fusion. Nuclear fission and fusion are the mechanisms used in the nuclear weapons that came to dominate international politics after the Second World War (1939–1945).

Gradually scientists discovered more and more particles – and today we have the standard model, which goes a long ...