Wave-particle duality

From Conservapedia

Wave-particle duality is the concept that matter and energy have both a wave nature and a particle nature. It is a fundamental result predicted by quantum mechanics.

Whether waves or particles are better suited for describing a system depends on the circumstances. For example, light is usually characterized as waves in most every-day applications, but photons (light particles) must be considered in some situations, such as the photoelectric effect and most particle physics experiments.