In the 17th Century, Newton and Huygens gave their own models of the composition of light. Newton said the light is made up of particles, which he called Corpuscles. In contrast, Huygens argued that light is a wave, a disturbance in the medium, just like the sound waves. Using their own theories of light, Newton and Huygens were able to explain refraction, reflection, shadows, rectilinear motion, and different colors of light. But since Newton had a greater reputation among the physicists back in the 17th century, it was his model of light that was accepted. However, in the year 1801, one of the most important experiments in the history of mankind was performed – Young’s double-slit experiment, which gave a fatal blow to Newton’s particle theory of light.