Principle of physics according to which the energy of interacting bodies or particles in a closed system remains constant, though it may take different forms (e.g., kinetic energy, potential energy, thermal energy, energy in an electric current, or energy stored in an electric field, in a magnetic field, or in chemical bonds [see bonding]). With the advent of relativity physics in 1905, mass was recognized as equivalent to energy. When accounting for a system of high-speed particles whose mass increases as a consequence of their speed, the laws of conservation of energy and conservation of mass become one conservation law. See also Hermann von Helmholtz.
This entry comes from Encyclopædia Britannica Concise.For the full entry on energy, conservation of, visit Britannica.com.
What made you look up energy, conservation of? Please tell us what you were reading, watching or discussing that led you here.
Take our visual vocab quiz
A quick quiz about stuff worth knowing
The commonly misspelled words quiz
The Vocab Quiz Game for iPhone & iPad
"Incredibly fun and addictive. And informative!" User Review, iTunes