Particles are Waves are Particles

At the beginning of the twentieth century, physicists again learned to view optical theory in an earlier light. In the seventeenth century Newton asserted that light was corpuscular or particle-like in nature. A century and a half later the work of luminaries like Thomas Young (1773 – 1829) and Augustin Jean Fresnel (1788 – 1827) definitely showed that, contrary to Newton's view, light was wave-like and not corpuscular, or particle-like, in nature. By passing light through a slit they demonstrated that light was diffracted just like a sound wave or water wave. It was only the very short wavelengths of visible light that had made it appear to travel like a particle in a straight line without spreading. This viewpoint was about to be reversed…