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conservation law
subject			fact

conservation law	has definition Law that identifies a quantity, such as energy, that remains unchanged throughout a transformation. All conservation laws are thought to involve symmetries.
	has definition A quantity that remains unchanged in the course of the evolution of a dynamical system. There are seven known quantities that are conserved: energy (including mass), momentum, angular momentum (including spin), charge, electron-family number, muon-family number, and baryon-family number.
	is a kind of law
law	has discoverer
theory	has validity correct or incorrect with caveats
	has author or reasearch group
	has domain a field of research
	has date or a range of dates for which the theory was active

Kinds of conservation law :

• conservation of angular momentum (4 facts) - The principle that the angular momentum of a system (the momentum of rotation about a point) remains the same as long as no external torque acts., The total angular momentum of an isolated dynamical system does not change during the course of its evolution.
• conservation of charge (2 facts)
• conservation of energy (4 facts) - The principle that the total energy of a closed system never changes, that energy is only converted from one form to another. This principle must be enlarged under special relativity to include mass-energy., The total energy of a system (including kinetic energy and gravitational energy) is conserved and does not vary. Thus, kinetic energy can only increase at the expense of gravitational potential energy. Modern physics has modified the law of conservation of energy, since matter can be created or annihilated; a more general law is the conservation of mass and energy.
• conservation of mass and energy (3 facts) - Important physical principle and one of the basic laws of physics stating that matter is neither created nor destroyed (although mass may become energy, the energy quantitatively represents the mass). One exception to this principle is a singularity; another follows from the theory of virtual particles.
• conservation of matter (3 facts) - The principle that matter is neither created nor destroyed. This principle is only approximately true, since special relativity shows that matter and energy are equivalent and interconvertible.
• conservation of momentum (3 facts) - The principle that the linear momentum of a system (in Newtonian mechanics, mass times velocity) remains the same as long as no external force acts.