How does quantum mechanics differ from classical physics?

Quantum mechanics differs from classical physics primarily in its description of matter and energy at the atomic and subatomic levels. Classical physics, based on Newton's laws of motion, treats physical quantities as continuous and deterministic. In contrast, quantum mechanics posits that many physical quantities are quantized, meaning they exist only in discrete values. Furthermore, quantum mechanics introduces inherent uncertainty, replacing the deterministic predictions of classical physics with probabilities. For instance, while classical physics assumes particles have definite positions and momenta, quantum mechanics, through the uncertainty principle, states that these cannot be known with perfect accuracy simultaneously. This leads to phenomena like wave-particle duality, where entities can exhibit characteristics of both waves and particles.123