Wave-particle duality

Wave-particle duality is the concept that particles may behave as waves and that waves may behave as particles. For example, light can be described and studied as light waves, or particle photons.

In 1905, Albert Einstein published his theory on the photoelectric effect, proposing that light could also behave as particles. This theory was expanded upon in 1924 by Louis de Broglie, a French physicist, who proposed that electrons and all matter can have wave properties. These complimentary hypotheses have since been tested and proven true resulting in today's acceptance that the properties of waves and particles can overlap.