- Wikipedia, Quantum mechanics
- Classical physics (the physics existing before quantum mechanics) derives from quantum
mechanics as an approximation valid only at macroscopic scales. Quantum
mechanics differs from classical physics in that: energy, momentum and other
quantities are often restricted to discrete values (quantization), objects have characteristics of both particles and waves (i.e. wave-particle
duality), and there are limits to the precision with which quantities can be
known (uncertainty principle).

- Alex St John, Life Needs Noise
- The math of quantum mechanics describes a constantly boiling foam of energy at the quantum level.