This lecture covers the detection of particles, including the use of scintillators, cloud chambers, and wire chambers, which rely on perturbations induced by passing particles. It explains ionization processes, tracking detectors, momentum measurement with magnetic fields, scintillation, and the use of silicon photomultipliers. The lecture also discusses the development of SciFi for LHCb, Cerenkov radiation, electromagnetic showers, electromagnetic calorimeters, and hadron calorimeters in particle physics experiments.