Conservation laws

In physics, a symmetry of a physical system is a physical or mathematical feature of the system (observed or intrinsic) that is preserved or remains unchanged under some transformation.

In mathematics and theoretical physics, an invariant is a property of a system which remains unchanged under some transformation.

In physics, a conservation law states that a particular measurable property of an isolated physical system does not change as the system evolves over time.

In quantum mechanics, a parity transformation (also called parity inversion) is the flip in the sign of one spatial coordinate.

A continuity equation in physics is an equation that describes the transport of some quantity.

Noether's (first) theorem states that every differentiable symmetry of the action of a physical system has a corresponding conservation law.

In physics, the law of conservation of energy states that the total energy of an isolated system remains constant—it is said to be conserved over time.

In physics, charge conservation is the principle that electric charge can neither be created nor destroyed.

In particle physics, the baryon number is a strictly conserved additive quantum number of a system.

In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational analog of linear momentum.

(This article is about momentum in physics. For other uses, see Momentum (disambiguation).) In classical mechanics, linear momentum, translational momentum, or simply momentum (pl. momenta; SI unit kg · m/s) is the product of the mass and velocity of an object, quantified in kilogram-meters per second.