How the Difference between Particles and Waves Disappeared

Abstract

Before James Maxwell discovered that light is an electromagnetic wave, scientists discussed the question of whether or not light is a stream of particles, similar to those considered in the previous chapter. Such particles have a rest mass and can be accelerated. The Dutch Christiaan Huygens (1629-1695) argued that light couldn’t be a stream of particles since two beams of light, in contrast to beams of water, intersect without affecting each other. Many scientists invested a lot of thought into how to experimentally determine whether light is a wave or a stream of particles.