Thomas Young's experiments

Thomas Young's experiments demonstrated that light behaves as a wave. He passed light through two tiny slits, creating patterns of bright and dark fringes on a screen—interference patterns—that occur only with waves overlapping constructively or destructively. This experiment provided strong evidence that light consists of waves, challenging the then-prevailing particle theory, and laid the foundation for the wave theory of light. His work helped us understand phenomena like diffraction and interference, crucial concepts in optics and physics.