* Thomas Young in 1801 performed his famous double-slit experiment, which demonstrated the wave-like nature of light by showing interference patterns. This provided strong evidence that light could behave like a wave.
* Albert Einstein in 1905 explained the photoelectric effect, which demonstrated the particle-like nature of light. This showed that light can interact with matter as if it were composed of individual packets of energy called photons.
Therefore, while Young's work emphasized the wave nature of light, Einstein's work added the particle aspect, solidifying the concept of wave-particle duality for light.
