Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. IN physics and chemistry, wave particle duality is the concept that all energy exhibits both wave-like and particle-like properties. BEing a central concept of quantum mechanics, this duality addresses the inadequacy of classical concepts like "particle" and "wave" in fully describing the behavior of quantum-scale objects. ORthodox interpretations of quantum mechanics explain this ostensible paradox as a fundamental property of the Universe, while alternative interpretations explain the duality as an emergent, second-order consequence of various limitations of the observer. THis treatment focuses on explaining the behavior from the perspective of the widely used Copenhagen interpretation.