This photograph is of the world’s first neutrino observed in a hydrogen bubble chamber. The event was produced in a synchronized cyclotron on November 13, 1970. The invisible neutrino follows the dashed yellow line and strikes a proton where three particle tracks originate. The neutrino turns into a muon (the long blue line). The short track (labeled p) is the proton. The third track is a pi-meson created by the collision.
In this unit, you will learn about the basic structure of the atomic nucleus.
Atoms of the same element always have the same number of protons in their nuclei, but may have differing numbers of electrons or neutrons. Radioactivity is the result of nuclear decay and the emission of sub-atomic particles. Quarks are the smallest particles known to date, and are the building blocks of the primary sub-atomic particles. Nuclear reactors release vast quantities of energy by harnessing the interactions of atomic nuclei.