Conservation law
For the legal aspects of environmental conservation, see conservation movement.
In physics, a conservation law states that a particular measurable property of an isolated physical system does not change as the system evolves. Any particular conservation law is a mathematical identity to certain symmetry of a physical system. A partial listing of conservation laws that are said to be exact laws, or more precisely have never been shown to be violated:
- Conservation of energy
- Conservation of linear momentum
- Conservation of angular momentum
- Conservation of electric charge
- Conservation of color charge
- Conservation of weak isospin
- Conservation of probability
There are also approximate conservation laws. These are approximately true in particular situations, such as low speeds, short time scales, or certain interactions.
- Conservation of mass (applies for low speeds)
- Conservation of baryon number (See chiral anomaly)
- Conservation of lepton number (In the Standard Model)
- Conservation of flavor (violated by the weak interaction)
- Conservation of parity
- CP symmetry
- Victor J. Stenger, 2000. Timeless Reality: Symmetry, Simplicity, and Multiple Universes. Buffalo NY: Prometheus Books. Chpt. 12 is a gentle introduction to symmetry, invariance, and conservation laws.
- Conservation Laws — an online textbook
