Nature’s Accelerators

Rutherford’s great idea to use radioactive sources for scattering experiments leads to Bohr’s model of the atom. Positrons, muons, pions, an V-particles that behave “strangely” are found in cosmic rays. The strong nuclear force and the weak interaction emerge as two fundamental forces besides electromagnetic forces and gravity. The strong force is responsible for the stability of atomic nuclei, whereas the weak interaction causes the spontaneous decay of particles that is associated with radioactivity. Photographic plates, cloud chambers, and Geiger counters are discussed as the detectors used to analyze subatomic reactions.