Conservation law
Concept · Physics, stage 1: Learn the vocabulary
A conservation law states that some measurable quantity in an isolated system stays the same as the system evolves. Energy, momentum, angular momentum, and electric charge are the standard examples. Conservation laws are not assumptions bolted onto physics; each one follows from a symmetry of the underlying laws, a result proved by Emmy Noether in 1918. When an apparent violation shows up in an experiment, physicists usually conclude that something has been overlooked rather than that the law has failed, and that reasoning has repeatedly led to the discovery of new particles.
Why it matters
Conservation laws let you predict the outcome of a process whose details you cannot compute, and they are the main tool for spotting when a measurement is incomplete.
Part of
Conservation law in the glossary
Sources
- Conservation law English Wikipedia
- Conservation of energy English Wikipedia
- Symmetry and Symmetry Breaking Stanford Encyclopedia of Philosophy
