Homestake Experiment

The Homestake Experiment was a scientific effort to detect neutrinos, tiny particles produced by the Sun's nuclear fusion. Scientists used a large tank of cleaning fluid deep underground to shield it from other cosmic particles. When solar neutrinos interacted with the chlorine in the fluid, they turned into argon atoms. By counting these argon atoms, scientists could measure how many neutrinos came from the Sun. The experiment found fewer neutrinos than expected, leading to the discovery of neutrino oscillation—meaning neutrinos change types—and revolutionized our understanding of particle physics and solar processes.