Elementary Particles and Cosmic Rays; Particle Detectors
The deepest layer of matter, the natural particle beam raining from space, and the instruments that let us see the invisible.
Big Idea: Everything is built from a small set of elementary particles that interact through four fundamental forces. Long before accelerators existed, nature supplied its own high-energy beam — cosmic rays — and physicists learned to reveal single particles with detectors such as the Geiger counter and the cloud chamber. This topic ties the three ideas together.
By the end you will be able to:
- name the main classes of elementary particles (leptons, hadrons, quarks, force carriers);
- list the four fundamental interactions and their carrier particles;
- explain what cosmic rays are, where they come from and how an air shower forms;
- describe how the Geiger–Muller counter, cloud chamber and scintillation counter work;
- use E0 = mc2 and r = mv/(qB) in simple particle problems.