Definition and Principles of Conservation of Energy
– The law of conservation of energy states that the total amount of energy within a closed system remains constant.
– Energy cannot be created or destroyed, but it can be transformed or transferred from one form to another.
– This principle applies to all forms of energy, including kinetic, potential, thermal, and chemical energy.
– Conservation of energy is a fundamental principle in physics and is supported by various scientific theories and laws.
– The conservation of energy can be proven mathematically through Noether’s theorem, which relates it to the symmetry of physical laws over time.
Relationship between Mass and Energy
– According to special relativity, mass and energy are interchangeable through the equation E=mc^2.
– Mass-energy equivalence means that any object with mass can potentially be converted into pure energy, and vice versa.
– This concept was first proposed by Albert Einstein and has been confirmed through various experiments and observations.
– The conversion of mass into energy is believed to occur in extreme conditions, such as during the Big Bang or in black holes.
– The conservation of mass-energy as a whole is now accepted in the scientific community.
Historical Development of Conservation of Energy
– Ancient philosophers like Thales of Miletus and Empedocles had early notions of the conservation of some underlying substance.
– Simon Stevin in 1605 and Galileo in 1639 made significant contributions to understanding the impossibility of perpetual motion.
– Christiaan Huygens’s laws of collision in 1669 highlighted the conservation of linear momenta and kinetic energies.
– Gottfried Leibniz introduced the concept of ‘vis viva’ or living force, which represented the approximate conservation of kinetic energy.
– Isaac Newton’s Principia in 1687 laid the foundation for the laws of motion and introduced the concept of force and momentum.
– Daniel Bernoulli formulated the principle of virtual work and the conservation of vis viva in 1715.
– Émilie du Châtelet conducted an experiment in the 18th century to test the conservation of total energy.
Concept of Energy Conversion
– Gradual realization that heat generated by motion under friction is a form of energy.
– Antoine Lavoisier and Pierre-Simon Laplace’s review of competing theories of vis viva and caloric theory.
– Count Rumford’s observations of heat generation during the boring of cannons.
– Introduction of the term ‘energy’ by Thomas Young in 1807.
– Gaspard-Gustave Coriolis and Jean-Victor Poncelet’s contribution to the conversion of kinetic energy to work.
– Demonstration of the mechanical equivalent of heat.
– Rejection of the caloric theory by Mikhail Lomonosov’s corpusculo-kinetic theory of heat.
Recognition and Acceptance of the Principle
– Hermann von Helmholtz’s conclusions similar to William Robert Grove’s theories.
– William Rankine’s use of the phrase ‘the law of the conservation of energy’.
– Peter Guthrie Tait’s claim that the principle originated with Sir Isaac Newton.
– General acceptance of the principle stemming from Helmholtz’s publication.
– Einstein’s theory of special relativity further supporting the principle of conservation of energy.
– Enrico Fermi proposed the correct description of beta-decay as the emission of an electron and an antineutrino.
– First law of thermodynamics.
– Emmy Noether’s theorem and energy conservation.
– Special relativity and energy conservation.
– General relativity and energy conservation.
– Quantum theory and energy conservation.
– Status of energy conservation. Source: https://en.wikipedia.org/wiki/Conservation_of_energy
In physics and chemistry, 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 the case of a closed system the principle says that the total amount of energy within the system can only be changed through energy entering or leaving the system. Energy can neither be created nor destroyed; rather, it can only be transformed or transferred from one form to another. For instance, chemical energy is converted to kinetic energy when a stick of dynamite explodes. If one adds up all forms of energy that were released in the explosion, such as the kinetic energy and potential energy of the pieces, as well as heat and sound, one will get the exact decrease of chemical energy in the combustion of the dynamite.
Classically, conservation of energy was distinct from conservation of mass. However, special relativity shows that mass is related to energy and vice versa by , the equation representing mass–energy equivalence, and science now takes the view that mass-energy as a whole is conserved. Theoretically, this implies that any object with mass can itself be converted to pure energy, and vice versa. However, this is believed to be possible only under the most extreme of physical conditions, such as likely existed in the universe very shortly after the Big Bang or when black holes emit Hawking radiation.
Given the stationary-action principle, conservation of energy can be rigorously proven by Noether's theorem as a consequence of continuous time translation symmetry; that is, from the fact that the laws of physics do not change over time.
A consequence of the law of conservation of energy is that a perpetual motion machine of the first kind cannot exist; that is to say, no system without an external energy supply can deliver an unlimited amount of energy to its surroundings. Depending on the definition of energy, conservation of energy can arguably be violated by general relativity on the cosmological scale.
