query: which law of thermodynamics is based on the conservation of energy law

pos: Laws of thermodynamics in several ways : More specifically, the First Law encompasses several principles: where denotes the amount of energy transferred into the system as heat. Combining these principles leads to one traditional statement of the first law of thermodynamics: it is not possible to construct a machine which will perpetually output work without an equal amount of energy input to that machine. Or more briefly, a perpetual motion machine of the first kind is impossible. The second law of thermodynamics indicates the irreversibility of natural processes, and, in many cases, the tendency of natural processes to lead towards spatial homogeneity of

pos: First law of thermodynamics (fluid mechanics) First law of thermodynamics (fluid mechanics) In physics, the first law of thermodynamics is an expression of the conservation of total energy of a system. The increase of the energy of a system is equal to the sum of work done on the system and the heat added to that system: where In fluid mechanics, the first law of thermodynamics takes the following form: where Because it expresses conservation of total energy, this is sometimes referred to as the energy balance equation of continuous media. The first law is used to derive the non-conservation form of the Navier–Stokes equations. Where

pos: First law of thermodynamics First law of thermodynamics The first law of thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic systems. The law of conservation of energy states that the total energy of an isolated system is constant; energy can be transformed from one form to another, but can be neither created nor destroyed. The first law is often formulated It states that the change in the internal energy of a closed system is equal to the amount of heat supplied "to" the system, minus the amount of work done "by" the system on its surroundings. An equivalent

pos: First law of thermodynamics (fluid mechanics) per unit mass equals proper energy per unit mass plus pressure times volume per unit mass (reciprocal of mass density). First law of thermodynamics (fluid mechanics) In physics, the first law of thermodynamics is an expression of the conservation of total energy of a system. The increase of the energy of a system is equal to the sum of work done on the system and the heat added to that system: where In fluid mechanics, the first law of thermodynamics takes the following form: where Because it expresses conservation of total energy, this is sometimes referred to as the energy

pos: First law of thermodynamics a distinction between bulk flow and diffusive flow of internal energy, the latter driven by a temperature gradient within the flowing material, and being defined with respect to the local center of mass of the bulk flow. In this case of a virtually closed system, because of the zero matter transfer, as noted above, one can safely distinguish between transfer of energy as work, and transfer of internal energy as heat. First law of thermodynamics The first law of thermodynamics is a version of the law of conservation of energy, adapted for thermodynamic systems. The law of conservation of energy

pos: Black hole thermodynamics "T" constant for thermal equilibrium for a normal system is analogous to formula_10 constant over the horizon of a stationary black hole. The left side, "dE", is the change in energy (proportional to mass). Although the first term does not have an immediately obvious physical interpretation, the second and third terms on the right side represent changes in energy due to rotation and electromagnetism. Analogously, the first law of thermodynamics is a statement of energy conservation, which contains on its right side the term "T dS". The second law is the statement of Hawking's area theorem. Analogously, the second law

pos: Biological thermodynamics Therefore, thermodynamics can explain the direction and rate of evolution along with the direction and rate of succession. The First Law of Thermodynamics is a statement of the conservation of energy; though it can be changed from one form to another, energy can be neither created nor destroyed. From the first law, a principle called Hess's Law arises. Hess’s Law states that the heat absorbed or evolved in a given reaction must always be constant and independent of the manner in which the reaction takes place. Although some intermediate reactions may be endothermic and others may be exothermic, the total

pos: Perpetual motion times. Modern designers and proponents often use other terms, such as "over unity", to describe their inventions. There is a scientific consensus that perpetual motion in an isolated system violates either the first law of thermodynamics, the second law of thermodynamics, or both. The first law of thermodynamics is a version of the law of conservation of energy. The second law can be phrased in several different ways, the most intuitive of which is that heat flows spontaneously from hotter to colder places; relevant here is that the law observes that in every macroscopic process, there is friction or something

pos: Robert Ayres (scientist) economic education today is that energy is the stuff of the universe, that all matter is also a form of energy, and that the economic system is essentially a system for extracting, processing and transforming energy as resources into energy embodied in products and services. This is a thermodynamic process, as the Rumanian economist Georgescu-Roegen said half a century ago (Georgescu-Roegen 1971). The economic process is subject to both the first law of thermodynamics (conservation of mass/energy; nothing can be created or destroyed) and the second law of thermodynamics (increasing entropy; all transformation processes are irreversible). The “first law” implies

pos: First law of thermodynamics occur and be calculated simultaneously. Putting the two complementary aspects together, the first law for a particular reversible process can be written This combined statement is the expression the first law of thermodynamics for reversible processes for closed systems. In particular, if no work is done on a thermally isolated closed system we have This is one aspect of the law of conservation of energy and can be stated: If, in a process of change of state of a closed system, the energy transfer is not under a practically zero temperature gradient and practically frictionless, then the process is irreversible.

pos: Second law of thermodynamics law was an empirical finding that was accepted as an axiom of thermodynamic theory. Statistical mechanics, classical or quantum, explains the microscopic origin of the law. The second law has been expressed in many ways. Its first formulation is credited to the French scientist Sadi Carnot, who in 1824 showed that there is an upper limit to the efficiency of conversion of heat to work, in a heat engine. The first law of thermodynamics provides the basic definition of internal energy, associated with all thermodynamic systems, and states the rule of conservation of energy. The second law is concerned with

pos: Thermodynamics thermodynamical equilibrium was implied in the other laws. The first, second, and third laws had been explicitly stated prior and found common acceptance in the physics community. Once the importance of the zeroth law for the definition of temperature was realized, it was impracticable to renumber the other laws, hence it was numbered the "zeroth law". The first law of thermodynamics is an expression of the principle of conservation of energy. It states that energy can be transformed (changed from one form to another), but cannot be created or destroyed. The first law is usually formulated by saying that the

pos: First law of thermodynamics law for closed systems, and admits heat calorimetrically defined along with work and internal energy. Another respected text defines heat exchange as determined by temperature difference, but also mentions that the Born (1921) version is "completely rigorous". These versions follow the traditional approach that is now considered out of date, exemplified by that of Planck (1897/1903). The first law of thermodynamics for closed systems was originally induced from empirically observed evidence, including calorimetric evidence. It is nowadays, however, taken to provide the definition of heat via the law of conservation of energy and the definition of work in terms of

pos: History of physics first law of thermodynamics—a restatement of the law of conservation of energy—which was stated around 1850 by William Thomson, later known as Lord Kelvin, and Rudolf Clausius. Lord Kelvin, who had extended the concept of absolute zero from gases to all substances in 1848, drew upon the engineering theory of Lazare Carnot, Sadi Carnot, and Émile Clapeyron–as well as the experimentation of James Prescott Joule on the interchangeability of mechanical, chemical, thermal, and electrical forms of work—to formulate the first law. Kelvin and Clausius also stated the second law of thermodynamics, which was originally formulated in terms of the fact

pos: Exergy impression of being a perpetual motion machine. Using actual conditions will give actual values, but standard ambient conditions are useful for initial design calculations. One goal of energy and exergy methods in engineering is to compute what comes into and out of several possible designs before a factory is built. Energy input and output will always balance according to the First Law of Thermodynamics or the energy conservation principle. Exergy output will not balance the exergy input for real processes since a part of the exergy input is always destroyed according to the Second Law of Thermodynamics for real processes.

pos: Adiabatic process the statement of the first law of thermodynamics, such as one based on empirical scales. Such a presupposition involves making the distinction between empirical temperature and absolute temperature. Rather, the definition of absolute thermodynamic temperature is best left till the second law is available as a conceptual basis. In the eighteenth century, the law of conservation of energy was yet to be fully formulated or established, and the nature of heat was debated. One approach to these problems was to regard heat, measured by calorimetry, as a primary substance that is conserved in quantity. By the middle of the nineteenth

pos: History of heat to those with less energetic molecules, and so lower internal energy. The work of Joule and Mayer demonstrated that heat and work were equivalent forms of energy, and led to the statement of the principle of the conservation of energy by Hermann von Helmholtz in 1847. Clausius demonstrated in 1850 that caloric theory could be reconciled with kinetic theory provided that the conservation of energy was employed rather than the movement of a substance, and stated the First Law of Thermodynamics. In 1851, William Thomson outlined the essentially modern view, as based on recent experiments by those such as James

pos: Energy disorder). This has been referred to as the inevitable thermodynamic heat death of the universe. In this heat death the energy of the universe does not change, but the fraction of energy which is available to do work through a heat engine, or be transformed to other usable forms of energy (through the use of generators attached to heat engines), grows less and less. The fact that energy can be neither created nor be destroyed is called the law of conservation of energy. In the form of the first law of thermodynamics, this states that a closed system's energy is

pos: Nicholas Georgescu-Roegen agents. Unlike a stock factor, a fund factor cannot be used (decumulated) at will, as its rate of utilisation depends on the distinct physical properties of the fund (labour power and farmland, for instance, may run the risk of overuse and exhaustion if proper care is not taken). Contrary to neoclassical production theory, Georgescu-Roegen identifies nature as the exclusive primary source of all factors of production. According to the first law of thermodynamics, matter and energy are neither created nor destroyed in the economy (the conservation principle). According to the second law of thermodynamics – the entropy law – what

pos: Inflation (cosmology) in a vast inflating background. Gravitational interactions, in this case, circumvent (but do not violate) the first law of thermodynamics (energy conservation) and the second law of thermodynamics (entropy and the arrow of time problem). However, while there is consensus that this solves the initial conditions problem, some have disputed this, as it is much more likely that the Universe came about by a quantum fluctuation. Don Page was an outspoken critic of inflation because of this anomaly. He stressed that the thermodynamic arrow of time necessitates low entropy initial conditions, which would be highly unlikely. According to them, rather

pos: Scientific law the conditions where they apply. Many laws take mathematical forms, and thus can be stated as an equation; for example, the law of conservation of energy can be written as formula_1, where E is the total amount of energy in the universe. Similarly, the first law of thermodynamics can be written as formula_2. The term "scientific law" is traditionally associated with the natural sciences, though the social sciences also contain laws. An example of a scientific law in social sciences is Zipf's law. Like theories and hypotheses, laws make predictions (specifically, they predict that new observations will conform to the

pos: First law of thermodynamics 1850 from Rudolf Clausius and from William Rankine; Rankine's statement is considered less distinct relative to Clausius'. A main aspect of the struggle was to deal with the previously proposed caloric theory of heat. In 1840, Germain Hess stated a conservation law for the so-called 'heat of reaction' for chemical reactions. His law was later recognized as a consequence of the first law of thermodynamics, but Hess's statement was not explicitly concerned with the relation between energy exchanges by heat and work. According to Truesdell (1980), Julius Robert von Mayer in 1841 made a statement that meant that "in a

pos: James Prescott Joule James Prescott Joule James Prescott Joule (; 24 December 1818 11 October 1889) was an English physicist, mathematician and brewer, born in Salford, Lancashire. Joule studied the nature of heat, and discovered its relationship to mechanical work (see energy). This led to the law of conservation of energy, which in turn led to the development of the first law of thermodynamics. The SI derived unit of energy, the joule, is named after him. Joule worked with Lord Kelvin to develop an absolute thermodynamic temperature scale, which came to be called the Kelvin scale. Joule also made observations of magnetostriction, and

pos: Biological thermodynamics primarily on photosynthesis. The total energy captured by photosynthesis in green plants from the solar radiation is about 2 x 10 joules of energy per year. Annual energy captured by photosynthesis in green plants is about 4% of the total sunlight energy that reaches Earth. The energy transformations in biological communities surrounding hydrothermal vents are exceptions; they oxidize sulfur, obtaining their energy via chemosynthesis rather than photosynthesis. The field of biological thermodynamics is focused on principles of chemical thermodynamics in biology and biochemistry. Principles covered include the first law of thermodynamics, the second law of thermodynamics, Gibbs free energy, statistical

pos: 19th century in science Carnot captured some of the ideas of thermodynamics in his discussion of the efficiency of an idealized engine. Sadi Carnot's work provided a basis for the formulation of the first law of thermodynamics—a restatement of the law of conservation of energy—which was stated around 1850 by William Thomson, later known as Lord Kelvin, and Rudolf Clausius. Lord Kelvin, who had extended the concept of absolute zero from gases to all substances in 1848, drew upon the engineering theory of Lazare Carnot, Sadi Carnot, and Émile Clapeyron–as well as the experimentation of James Prescott Joule on the interchangeability of mechanical, chemical,

pos: Pessimism with pessimistic assessments of the role of technology in the modern world. 'Entropy pessimism' represents a special case of technological and environmental pessimism, based on thermodynamic principles. According to the first law of thermodynamics, matter and energy is neither created nor destroyed in the economy. According to the second law of thermodynamics — also known as the entropy law — what happens in the economy is that all matter and energy is transformed from states available for human purposes (valuable natural resources) to states unavailable for human purposes (valueless waste and pollution). In effect, all of man's technologies and activities

pos: Hess's law Hess's law Hess' law of constant heat summation, also known as Hess' law (or Hess's law), is a relationship in physical chemistry named after Germain Hess, a Switzerland-born Russian chemist and physician who published it in 1840. The law states that the total enthalpy change during the complete course of a chemical reaction is the same whether the reaction is made in one step or in several steps. Hess' law is now understood as an expression of the principle of conservation of energy, also expressed in the first law of thermodynamics, and the fact that the enthalpy of a chemical

pos: James Prescott Joule (1850–1922), a daughter, Alice Amelia (1852–1899) and a second son, Henry (born 1854, who died three weeks later). James Prescott Joule James Prescott Joule (; 24 December 1818 11 October 1889) was an English physicist, mathematician and brewer, born in Salford, Lancashire. Joule studied the nature of heat, and discovered its relationship to mechanical work (see energy). This led to the law of conservation of energy, which in turn led to the development of the first law of thermodynamics. The SI derived unit of energy, the joule, is named after him. Joule worked with Lord Kelvin to develop an absolute

pos: Julius von Mayer Julius von Mayer Julius Robert Mayer (November 25, 1814 – March 20, 1878) was a German physician, chemist and physicist and one of the founders of thermodynamics. He is best known for enunciating in 1841 one of the original statements of the conservation of energy or what is now known as one of the first versions of the first law of thermodynamics, namely that "energy can be neither created nor destroyed". In 1842, Mayer described the vital chemical process now referred to as oxidation as the primary source of energy for any living creature. His achievements were overlooked and priority

pos: First law of thermodynamics forward and backward quasi-static adiabatic stages, with isothermal stages of zero magnitude. Sometimes the concept of internal energy is not made explicit in the statement. Sometimes the existence of the internal energy is made explicit but work is not explicitly mentioned in the statement of the first postulate of thermodynamics. Heat supplied is then defined as the residual change in internal energy after work has been taken into account, in a non-adiabatic process. A respected modern author states the first law of thermodynamics as "Heat is a form of energy", which explicitly mentions neither internal energy nor adiabatic work. Heat

pos: Temperature thermodynamics: "All diathermal walls are equivalent." Thus the present definition of thermodynamic temperature rests on the zeroth law of thermodynamics. Explicitly, this present definition of thermodynamic temperature also rests on the first law of thermodynamics, for the determination of amounts of energy transferred as heat. Implicitly for this definition, the second law of thermodynamics provides information that establishes the virtuous character of the temperature so defined. It provides that any working substance that complies with the requirement stated in this definition will lead to the same ratio of thermodynamic temperatures, which in this sense is universal, or absolute. The second

pos: Conservation of energy then-current assumption that beta decay is the simple emission of an electron from a nucleus. This problem was eventually resolved in 1933 by Enrico Fermi who proposed the correct description of beta-decay as the emission of both an electron and an antineutrino, which carries away the apparently missing energy. For a closed thermodynamic system, the first law of thermodynamics may be stated as: where formula_10 is the quantity of energy added to the system by a heating process, formula_11 is the quantity of energy lost by the system due to work done by the system on its surroundings and formula_12

pos: Biological thermodynamics this energy from the sunlight and undergo photosynthesis, effectively converting solar energy into chemical energy. To transfer the energy once again, animals will feed on plants and use the energy of digested plant materials to create biological macromolecules. The biological evolution may be explained through a thermodynamic theory. The four laws of thermodynamics are used to frame the biological theory behind evolution. The first law of thermodynamics states that states that energy can not be created or destroyed. No life can create energy but must obtain it through its environment. The second law of thermodynamics states that energy can be

pos: Energy energy and not its absolute value, which is impossible to determine with thermodynamics alone. The first law of thermodynamics asserts that energy (but not necessarily thermodynamic free energy) is always conserved and that heat flow is a form of energy transfer. For homogeneous systems, with a well-defined temperature and pressure, a commonly used corollary of the first law is that, for a system subject only to pressure forces and heat transfer (e.g., a cylinder-full of gas) without chemical changes, the differential change in the internal energy of the system (with a "gain" in energy signified by a positive quantity) is

pos: Entropy The first law of thermodynamics, deduced from the heat-friction experiments of James Joule in 1843, expresses the concept of energy, and its conservation in all processes; the first law, however, is unable to quantify the effects of friction and dissipation. In the 1850s and 1860s, German physicist Rudolf Clausius objected to the supposition that no change occurs in the working body, and gave this "change" a mathematical interpretation by questioning the nature of the inherent loss of usable heat when work is done, e.g. heat produced by friction. Clausius described entropy as the "transformation-content", i.e. dissipative energy use, of a

pos: First law of thermodynamics view. Most careful textbook statements of the law express it for closed systems. It is stated in several ways, sometimes even by the same author. For the thermodynamics of closed systems, the distinction between transfers of energy as work and as heat is central and is within the scope of the present article. For the thermodynamics of open systems, such a distinction is beyond the scope of the present article, but some limited comments are made on it in the section below headed 'First law of thermodynamics for open systems'. There are two main ways of stating a law of

pos: Thermochemical equation the equation is changed through multiplication, then all agents must be proportionally changed, including ΔH. (See Manipulating Thermochemical Equations, below.) Thermochemical equation’s multiplicative property is largely due to the First Law of Thermodynamics, which says that energy can be neither created nor destroyed, a concept commonly known as the conservation of energy. It holds true on a physical or molecular scale. Thermochemical equations can be changed, as mentioned above, by multiplying by any numerical coefficient. All agents must be multiplied, including ΔH. Using the thermochemical equation of variables as above, one gets the following example. Assume that one needs to

pos: Human impact on the environment perceived as unavoidable for several reasons. First, given that the purpose of many technologies is to exploit, control, or otherwise “improve” upon nature for the perceived benefit of humanity while at the same time the myriad of processes in nature have been optimized and are continually adjusted by evolution, any disturbance of these natural processes by technology is likely to result in negative environmental consequences. Second, the conservation of mass principle and the first law of thermodynamics (i.e., conservation of energy) dictate that whenever material resources or energy are moved around or manipulated by technology, environmental consequences are inescapable. Third,

pos: Fluid dynamics conservation of energy (also known as First Law of Thermodynamics). These are based on classical mechanics and are modified in quantum mechanics and general relativity. They are expressed using the Reynolds transport theorem. In addition to the above, fluids are assumed to obey the . Fluids are composed of molecules that collide with one another and solid objects. However, the continuum assumption assumes that fluids are continuous, rather than discrete. Consequently, it is assumed that properties such as density, pressure, temperature, and flow velocity are well-defined at infinitesimally small points in space and vary continuously from one point to another.

pos: First law of thermodynamics impermeability and permeability (explicitly including walls that are permeable only to heat). Carathéodory's 1909 version of the first law of thermodynamics was stated in an axiom which refrained from defining or mentioning temperature or quantity of heat transferred. That axiom stated that the internal energy of a phase in equilibrium is a function of state, that the sum of the internal energies of the phases is the total internal energy of the system, and that the value of the total internal energy of the system is changed by the amount of work done adiabatically on it, considering work as a

pos: Internal energy closed. Then the first law of thermodynamics states that the increase in internal energy is equal to the total heat added plus the work done on the system by its surroundings. If the containing walls pass neither matter nor energy, the system is said to be isolated and its internal energy cannot change. The first law of thermodynamics may be regarded as establishing the existence of the internal energy. The internal energy is one of the two cardinal state functions of the state variables of a thermodynamic system. The internal energy of a given state of a system cannot be

pos: Exergy exergy content less than their energy content. The exact proportion of exergy in a substance depends on the amount of entropy relative to the surrounding environment as determined by the Second Law of Thermodynamics. Exergy is useful when measuring the efficiency of an energy conversion process. The exergetic, or 2nd Law, efficiency is a ratio of the exergy output divided by the exergy input. This formulation takes into account the quality of the energy, often offering a more accurate and useful analysis than efficiency estimates only using the First Law of Thermodynamics. Work can be extracted also from bodies colder

pos: Thermodynamic equations "insulated" to changes to that parameter from the outside. The truth of this statement for volume is trivial, for particles one might say that the total particle number of each atomic element is conserved. In the case of energy, the statement of the conservation of energy is known as the first law of thermodynamics. A thermodynamic system is in equilibrium when it is no longer changing in time. This may happen in a very short time, or it may happen with glacial slowness. A thermodynamic system may be composed of many subsystems which may or may not be "insulated" from

pos: First law of thermodynamics statement of the first law of thermodynamics for a transfer between two otherwise isolated open systems, that fits well with the conceptually revised and rigorous statement of the law stated above. For the thermodynamic operation of adding two systems with internal energies and , to produce a new system with internal energy , one may write ; the reference states for , and should be specified accordingly, maintaining also that the internal energy of a system be proportional to its mass, so that the internal energies are extensive variables. There is a sense in which this kind of additivity expresses

pos: Adiabatic wall is historically older. The other (which will here be referred to as the mechanical stream) is from a primarily theoretical viewpoint, to define it as a residual quantity after transfers of energy as macroscopic work, between two bodies or closed systems, have been determined for a process, so as to conform with the principle of conservation of energy or the first law of thermodynamics for closed systems; this approach grew in the twentieth century, though was partly manifest in the nineteenth. In the thermodynamic stream of thinking, the specified mechanisms of heat transfer are conduction and radiation. These mechanisms presuppose

pos: First law of thermodynamics process at constant pressure, the heat used to produce expansion is universally interconvertible with work", but this is not a general statement of the first law. The original nineteenth century statements of the first law of thermodynamics appeared in a conceptual framework in which transfer of energy as heat was taken as a primitive notion, not defined or constructed by the theoretical development of the framework, but rather presupposed as prior to it and already accepted. The primitive notion of heat was taken as empirically established, especially through calorimetry regarded as a subject in its own right, prior to thermodynamics.

pos: First law of thermodynamics of transfer of energy as heat. In this example, kinetic energy of bulk flow and potential energy with respect to long-range external forces such as gravity are both considered to be zero. The first law of thermodynamics refers to the change of internal energy of the open system, between its initial and final states of internal equilibrium. An open system can be in contact equilibrium with several other systems at once. This includes cases in which there is contact equilibrium between the system, and several subsystems in its surroundings, including separate connections with subsystems through walls that are permeable to

pos: Energy (psychological) revolution" xv.192, 1944). In 1874, the concept of "psychodynamics" was proposed with the publication of "Lectures on Physiology" by German physiologist Ernst Wilhelm von Brücke who, in coordination with physicist Hermann von Helmholtz, one of the formulators of the first law of thermodynamics (conservation of energy), supposed that all living organisms are energy-systems also governed by this principle. During this year, at the University of Vienna, Brücke served as supervisor for first-year medical student Sigmund Freud who adopted this new "dynamic" physiology. In his "Lectures on Physiology", Brücke set forth the then-radical view that the living organism is a dynamic

pos: Second law of thermodynamics the first law of thermodynamics, the change "dU" in the internal energy of the sub-system is the sum of the heat "δq" added to the sub-system, "less" any work "δw" done "by" the sub-system, "plus" any net chemical energy entering the sub-system "d ∑μN", so that: where μ are the chemical potentials of chemical species in the external surroundings. Now the heat leaving the reservoir and entering the sub-system is where we have first used the definition of entropy in classical thermodynamics (alternatively, in statistical thermodynamics, the relation between entropy change, temperature and absorbed heat can be derived); and then

pos: Adiabatic process first law of thermodynamics then implies that the net internal energy change of the system is zero. For an ideal gas, the temperature remains constant because the internal energy only depends on temperature in that case. Since at constant temperature, the entropy is proportional to the volume, the entropy increases in this case, therefore this process is irreversible. The definition of an adiabatic process is that heat transfer to the system is zero, . Then, according to the first law of thermodynamics, where is the change in the internal energy of the system and is work done "by" the system.

pos: Euler equations (fluid dynamics) derivatives: formula_61 Finally, the energy equation: formula_62 can be furtherly simplified in convective form by changing variable from specific energy to the specific entropy: in fact the first law of thermodynamics in local form can be written: formula_63 by substituting the material derivative of the internal energy, the energy equation becomes: formula_64 now the term between parenthesis is identically zero according to the conservation of mass, then the Euler energy equation becomes simply: formula_65 For a thermodynamic fluid, the compressible Euler equations are consequently best written as: \end{align}\right.</math> where: Note that, in the general case and not only in the

neg: Chemical law Chemical law Chemical laws are those laws of nature relevant to chemistry. The most fundamental concept in chemistry is the law of conservation of mass, which states that there is no detectable change in the quantity of matter during an ordinary chemical reaction. Modern physics shows that it is actually energy that is conserved, and that energy and mass are related; a concept which becomes important in nuclear chemistry. Conservation of energy leads to the important concepts of equilibrium, thermodynamics, and kinetics. Additional laws of chemistry elaborate on the law of conservation of mass. Joseph Proust's law of definite composition

neg: Nicholas Georgescu-Roegen that both main streams of economic thought having dominated the world since the end of the 19th century – namely neoclassical economics and Marxism – share the shortcoming of not taking into account the importance of natural resources in man's economy. Hence, Georgescu-Roegen engages himself in an intellectual battle with two fronts. The physical theory of thermodynamics is based on two laws: The first law states that energy is neither created nor destroyed in any isolated system (a conservation principle). The second law of thermodynamics – also known as the entropy law – states that energy tends to be degraded

neg: Scientific law energy that is conserved, and that energy and mass are related; a concept which becomes important in nuclear chemistry. Conservation of energy leads to the important concepts of equilibrium, thermodynamics, and kinetics. Additional laws of chemistry elaborate on the law of conservation of mass. Joseph Proust's law of definite composition says that pure chemicals are composed of elements in a definite formulation; we now know that the structural arrangement of these elements is also important. Dalton's law of multiple proportions says that these chemicals will present themselves in proportions that are small whole numbers (i.e. 1:2 for Oxygen:Hydrogen ratio in

neg: Chemical thermodynamics chemical thermodynamics is typically used to predict the energy exchanges that occur in the following processes: The following state functions are of primary concern in chemical thermodynamics: Most identities in chemical thermodynamics arise from application of the first and second laws of thermodynamics, particularly the law of conservation of energy, to these state functions. The 3 laws of thermodynamics: Chemical energy is the potential of a chemical substance to undergo a transformation through a chemical reaction or to transform other chemical substances. Breaking or making of chemical bonds involves energy or heat, which may be either absorbed or evolved from

neg: Vacuum energy a relative sense, which is not true if we can observe it indirectly via the cosmological constant. The existence of vacuum energy is also sometimes used as theoretical justification for the possibility of free-energy machines. It has been argued that due to the broken symmetry (in QED), free energy does not violate conservation of energy, since the laws of thermodynamics only apply to equilibrium systems. However, consensus amongst physicists is that this is unknown as the nature of vacuum energy remains an unsolved problem. In particular, the second law of thermodynamics is unaffected by the existence of vacuum energy. However,

neg: The Natural Step heat radiation. Earth's biosphere is a (relatively) closed system regarding matter, some meteorites and dust enter and only limited matter leaves due to gravity (e.g. some space rockets, dust). The First and Second Laws of Thermodynamics (LoTD) and Laws for conservation of matter (LCoM) set limiting conditions for life on earth: The First Law says that energy is conserved; nothing disappears, its form simply changes (e.g. heat, movement). Another way of stating this is: "Energy cannot be created, or destroyed, only modified in form." The implications of the Second Law and second law of conservation of matter, are that matter

neg: Energy as the field of thermodynamics. Thermodynamics aided the rapid development of explanations of chemical processes by Rudolf Clausius, Josiah Willard Gibbs, and Walther Nernst. It also led to a mathematical formulation of the concept of entropy by Clausius and to the introduction of laws of radiant energy by Jožef Stefan. According to Noether's theorem, the conservation of energy is a consequence of the fact that the laws of physics do not change over time. Thus, since 1918, theorists have understood that the law of conservation of energy is the direct mathematical consequence of the translational symmetry of the quantity conjugate

neg: Atmospheric thermodynamics models. The atmosphere is an example of a non-equilibrium system. Atmospheric thermodynamics describes the effect of buoyant forces that cause the rise of less dense (warmer) air, the descent of more dense air, and the transformation of water from liquid to vapor (evaporation) and its condensation. Those dynamics are modified by the force of the pressure gradient and that motion is modified by the Coriolis force. The tools used include the law of energy conservation, the ideal gas law, specific heat capacities, the assumption of isentropic processes (in which entropy is a constant), and moist adiabatic processes (during which no

neg: Michele Trancossi second law of thermodynamics for vehicles, increse of energy efficiency of electric and hybrid aircrafts, high energy efficiency container housing with peltier cells based acclimatization for social housing. He also published 24 papers with Bachelor students. Recently, he placed in quescence for developing start-up companies to exploit the ideas produced with bachelor students about fluid dynamic models based on the second law of thermodynamics, a new CFD using Bejan number as dimensionless variable, innovative concepts of drones, to the demonstration of the necessity of open access dissemination of the research and open source software according to second law of thermodynamics.

neg: First law of thermodynamics form of energy. That article considered this statement to be an expression of the law of conservation of energy for such systems. This version is nowadays widely accepted as authoritative, but is stated in slightly varied ways by different authors. Such statements of the first law for closed systems assert the existence of internal energy as a function of state defined in terms of adiabatic work. Thus heat is not defined calorimetrically or as due to temperature difference. It is defined as a residual difference between change of internal energy and work done on the system, when that work does

neg: Rudolf Clausius some have used. His most famous paper, "Ueber die bewegende Kraft der Wärme" ("On the Moving Force of Heat and the Laws of Heat which may be Deduced Therefrom") was published in 1850, and dealt with the mechanical theory of heat. In this paper, he showed that there was a contradiction between Carnot's principle and the concept of conservation of energy. Clausius restated the two laws of thermodynamics to overcome this contradiction (the third law was developed by Walther Nernst, during the years 1906–1912). This paper made him famous among scientists. Clausius' most famous statement of thermodynamics second law was

neg: Richard D. Feinman law of thermodynamics (conservation of energy) is a bookkeeping law, that it does not say how energy input is divided between weight gain, work done, heat generation or storage of energy in different biomolecules. The second law is a dissipation law. It says that all (real) processes are inefficient. Feinman explained how diets of different composition vary in efficiency, in particular, how carbohydrate-restricted diets can lead to reduced efficiency. Whereas the effect is not always seen, the argument is that there is no reason to doubt published reports where it does occur. He is a director of the Metabolism Society

neg: Caloric theory Clausius published a paper showing that the two theories were indeed compatible, as long as the calorists' principle of the conservation of heat was replaced by a principle of conservation of energy. In this way, the caloric theory was absorbed into the annals of physics, and evolved into modern thermodynamics, in which heat is the kinetic energy of some particles (atoms, molecules) of the substance. In later combination with the law of energy conservation, the caloric theory still shows a very valuable physical insight into some aspects of heat, for example, the emergence of Laplace's equation and Poisson's equation in

neg: First law of thermodynamics rate of transfer zero. The two thermodynamic parameters that form a generalized force-displacement pair are called "conjugate variables". The two most familiar pairs are, of course, pressure-volume, and temperature-entropy. Classical thermodynamics is initially focused on closed homogeneous systems (e.g. Planck 1897/1903), which might be regarded as 'zero-dimensional' in the sense that they have no spatial variation. But it is desired to study also systems with distinct internal motion and spatial inhomogeneity. For such systems, the principle of conservation of energy is expressed in terms not only of internal energy as defined for homogeneous systems, but also in terms of kinetic

neg: Physical cosmology total energy is conserved in an expanding universe. For instance, each photon that travels through intergalactic space loses energy due to the redshift effect. This energy is not obviously transferred to any other system, so seems to be permanently lost. On the other hand, some cosmologists insist that energy is conserved in some sense; this follows the law of conservation of energy. Thermodynamics of the universe is a field of study that explores which form of energy dominates the cosmos – relativistic particles which are referred to as radiation, or non-relativistic particles referred to as matter. Relativistic particles are particles

neg: Conservation of energy some chemists such as William Hyde Wollaston. Academics such as John Playfair were quick to point out that kinetic energy is clearly not conserved. This is obvious to a modern analysis based on the second law of thermodynamics, but in the 18th and 19th centuries the fate of the lost energy was still unknown. Gradually it came to be suspected that the heat inevitably generated by motion under friction was another form of "vis viva". In 1783, Antoine Lavoisier and Pierre-Simon Laplace reviewed the two competing theories of "vis viva" and caloric theory. Count Rumford's 1798 observations of heat generation

neg: Le Sage's theory of gravitation assertion: Likewise Isenkrahe's violation of the energy conservation law is unacceptable, and Kelvin's application of Clausius' theorem leads (as noted by Kelvin himself) to some sort of perpetual motion mechanism. The suggestion of a secondary re-radiation mechanism for wave models attracted the interest of JJ Thomson, but was not taken very seriously by either Maxwell or Poincaré, because it entails a gross violation of the second law of thermodynamics (huge amounts of energy spontaneously being converted from a colder to a hotter form), which is one of the most solidly established of all physical laws. The energy problem has also

neg: Carnot's theorem (thermodynamics) hot reservoir. Based on modern thermodynamics, Carnot's theorem is a result of the second law of thermodynamics. Historically, it was based on contemporary caloric theory and preceded the establishment of the second law. The proof of the Carnot theorem is a proof by contradiction, or reductio ad absurdum, as illustrated by the figure showing two heat engines operating between two reservoirs of different temperature. The heat engine with more efficiency (formula_3) is driving a heat engine with less efficiency (formula_4), causing the latter to act as a heat pump. This pair of engines receives no outside energy, and operates solely

neg: Compressible flow of mass. To achieve this decrease in density, the flow must expand, and to do so, the flow must pass through a diverging duct. See image of de Laval Nozzle. Ultimately, because of the energy conservation law, a gas is limited to a certain maximum velocity based on its energy content. The maximum velocity, V, that a gas can attain is: where c is the specific heat of the gas and T is the stagnation temperature of the flow. Using conservations laws and thermodynamics, a number of relationships of the form can be obtained, where M is the Mach number

neg: Zero-point energy the traditional conservation laws in classical and quantum electrodynamics (QED) only display linear U(1) symmetry (in particular, by the extended Noether theorem, conservation laws such as the laws of thermodynamics need not always apply to dissipative systems, which are expressed in gauges of higher symmetry). The second law of thermodynamics states that in a closed linear system entropy flow can only be positive (or exactly zero at the end of a cycle). However, negative entropy (i.e. increased order, structure or self-organisation) can spontaneously appear in an open nonlinear thermodynamic system that is far from equilibrium, so long as this emergent

neg: Second law of thermodynamics the significance of James Prescott Joule's work on the conservation of energy, Rudolf Clausius was the first to formulate the second law during 1850, in this form: heat does not flow "spontaneously" from cold to hot bodies. While common knowledge now, this was contrary to the caloric theory of heat popular at the time, which considered heat as a fluid. From there he was able to infer the principle of Sadi Carnot and the definition of entropy (1865). Established during the 19th century, the Kelvin-Planck statement of the Second Law says, "It is impossible for any device that operates on

neg: First law of thermodynamics also be transferred from one thermodynamic system to another in association with transfer of matter. Born points out that in general such energy transfer is not resolvable uniquely into work and heat moieties. In general, when there is transfer of energy associated with matter transfer, work and heat transfers can be distinguished only when they pass through walls physically separate from those for matter transfer. The "mechanical" approach postulates the law of conservation of energy. It also postulates that energy can be transferred from one thermodynamic system to another adiabatically as work, and that energy can be held as the

neg: Thermodynamics systems that are far from equilibrium are still debatable. One of such principles is the maximum entropy production principle. It states that non-equilibrium systems behave such a way as to maximize its entropy production. In classical thermodynamics, the second law is a basic postulate applicable to any system involving heat energy transfer; in statistical thermodynamics, the second law is a consequence of the assumed randomness of molecular chaos. There are many versions of the second law, but they all have the same effect, which is to explain the phenomenon of irreversibility in nature. The third law of thermodynamics is a

neg: Isolated system An isolated system obeys the conservation law that its total energy–mass stays constant. Most often, in thermodynamics, matter and energy are treated as separately conserved. Because of the requirement of enclosure, and the near ubiquity of gravity, strictly and ideally isolated systems do not actually occur in experiments or in nature. Though very useful, they are strictly hypothetical. Classical thermodynamics is usually presented as postulating the existence of isolated systems. It is also usually presented as the fruit of experience. Obviously, no experience has been reported of an ideally isolated system. It is, however, the fruit of experience that some

neg: Third law of thermodynamics law of thermodynamics concerns thermodynamic processes at a fixed, low temperature: Here a condensed system refers to liquids and solids. A classical formulation by Nernst (actually a consequence of the Third Law) is: There also exists a formulation of the Third Law which approaches the subject by postulating a specific energy behavior: The 3rd law was developed by the chemist Walther Nernst during the years 1906–12, and is therefore often referred to as Nernst's theorem or Nernst's postulate. The third law of thermodynamics states that the entropy of a system at absolute zero is a well-defined constant. This is because

neg: Experimental physics and Newton's law of universal gravitation, which describes the fundamental force of gravity. Both theories agreed well with experiment. The "Principia" also included several theories in fluid dynamics. From the late 17th century onward, thermodynamics was developed by physicist and chemist Boyle, Young, and many others. In 1733, Bernoulli used statistical arguments with classical mechanics to derive thermodynamic results, initiating the field of statistical mechanics. In 1798, Thompson demonstrated the conversion of mechanical work into heat, and in 1847 Joule stated the law of conservation of energy, in the form of heat as well as mechanical energy. Ludwig Boltzmann, in

neg: Thermoeconomics non-equilibrium thermodynamics to model these activities. In thermodynamic terminology, human economic activity may be described as a dissipative system, which flourishes by consuming free energy in transformations and exchange of resources, goods, and services. Thermoeconomics is based on the proposition that the role of energy in biological evolution should be defined and understood not through the second law of thermodynamics but in terms of such economic criteria as productivity, efficiency, and especially the costs and benefits (or profitability) of the various mechanisms for capturing and utilizing available energy to build biomass and do work. Thermoeconomics Thermoeconomics, also referred to as

neg: Wien's displacement law displacement law may be referred to as "Wien's law", a term which is also used for the Wien approximation. Wien's displacement law is relevant to some everyday experiences: The law is named for Wilhelm Wien, who derived it in 1893 based on a thermodynamic argument. Wien considered adiabatic expansion of a cavity containing waves of light in thermal equilibrium. He showed that, under slow expansion or contraction, the energy of light reflecting off the walls changes in exactly the same way as the frequency. A general principle of thermodynamics is that a thermal equilibrium state, when expanded very slowly, stays

neg: First law of thermodynamics the two component isolated systems. Two previously isolated systems can be subjected to the thermodynamic operation of placement between them of a wall permeable to matter and energy, followed by a time for establishment of a new thermodynamic state of internal equilibrium in the new single unpartitioned system. The internal energies of the initial two systems and of the final new system, considered respectively as closed systems as above, can be measured. Then the law of conservation of energy requires that where and denote the changes in internal energy of the system and of its surroundings respectively. This is a

neg:
Ginsberg's theorem The "theorem" is given as a restatement of the consequences of the zeroth, first, second, and third laws of thermodynamics, with regard to the usable energy of a closed system: 0. There is a game (consequence of zeroth law of thermodynamics)
 1. You can't win. (consequence of first law of thermodynamics)
 2. You can't break even. (consequence of second law of thermodynamics)
 3. You can't even get out of the game. (consequence of third law of thermodynamics)
 It is sometimes stated as a general adage without specific reference to the laws of thermodynamics. Ginsberg's theorem Ginsberg's theorem is a parody

neg: Negative resistance power, so from the passive sign convention formula_20. Therefore, from Joule's law formula_21. In other words, no material can conduct electric current better than a "perfect" conductor with zero resistance. For a passive device to have formula_22 would violate either conservation of energy or the second law of thermodynamics, "(diagram)". Therefore, some authors state that static resistance can never be negative. However it is easily shown that the ratio of voltage to current v/i at the terminals of any power source (AC or DC) is negative. For electric power (potential energy) to flow out of a device into the circuit,

neg: Heat primitive concept, which contributes, by scientific induction to knowledge of the law of conservation of energy. This view is widely taken as the practical one, quantity of heat being measured by calorimetry. Bailyn also distinguishes the two macroscopic approaches as the mechanical and the thermodynamic. The thermodynamic view was taken by the founders of thermodynamics in the nineteenth century. It regards quantity of energy transferred as heat as a primitive concept coherent with a primitive concept of temperature, measured primarily by calorimetry. A calorimeter is a body in the surroundings of the system, with its own temperature and internal energy;

neg: Third law of thermodynamics Third law of thermodynamics The third law of thermodynamics is sometimes stated as follows, regarding the properties of closed systems in thermodynamic equilibrium: This constant value cannot depend on any other parameters characterizing the closed system, such as pressure or applied magnetic field. At absolute zero (zero kelvin) the system must be in a state with the minimum possible energy. Entropy is related to the number of accessible microstates, and there is typically one unique state (called the ground state) with minimum energy. In such a case, the entropy at absolute zero will be exactly zero. If the system does

neg: Conservation Law Foundation Conservation Law Foundation Conservation Law Foundation (CLF) is an environmental advocacy organization based in New England. Since 1966, CLF's mission has been to advocate on behalf of the region's environment and its communities. CLF's advocacy work takes place in four program areas: Clean Energy & Climate Change, Clean Water & Healthy Forests, Healthy Oceans and Smart Growth. CLF works to promote renewable energy and fight air and water pollution; build healthy fishing communities and protect marine habitat; fight sprawl, promote public transit and defend public health. Conservation Law Foundation is a nonprofit, member-supported organization with offices in Maine, Massachusetts, New

neg: Alternatives to general relativity of drag, which is not observed. Other models are violating the energy conservation law and are incompatible with modern thermodynamics. At the end of the 19th century, many tried to combine Newton's force law with the established laws of electrodynamics, like those of Weber, Carl Friedrich Gauss, Bernhard Riemann and James Clerk Maxwell. Those models were used to explain the perihelion advance of Mercury. In 1890, Lévy succeeded in doing so by combining the laws of Weber and Riemann, whereby the speed of gravity is equal to the speed of light in his theory. And in another attempt, Paul Gerber

neg: Heat The uniqueness of work in this scheme is considered to guarantee rigor and purity of conception. The conceptual purity of this definition, based on the concept of energy transferred as work as an ideal notion, relies on the idea that some frictionless and otherwise non-dissipative processes of energy transfer can be realized in physical actuality. The second law of thermodynamics, on the other hand, assures us that such processes are not found in nature. Before the rigorous mathematical definition of heat based on Carathéodory's 1909 paper, historically, heat, temperature, and thermal equilibrium were presented in thermodynamics textbooks as jointly primitive

neg: History of energy biological thermodynamics and thermoeconomics, to name a couple; as well as related terms such as entropy, a measure of the loss of useful energy, or power, an energy flow per unit time, etc. In the past two centuries, the use of the word energy in various "non-scientific" vocations, e.g. social studies, spirituality and psychology has proliferated the popular literature. In 1918 it was proved that the law of conservation of energy is the direct mathematical consequence of the translational symmetry of the quantity conjugate to energy, namely time. That is, energy is conserved because the laws of physics do not

neg: Energy more degrees of freedom (i.e., given new available energy states that are the same as existing states), then total energy spreads over all available degrees equally without distinction between "new" and "old" degrees. This mathematical result is called the second law of thermodynamics. The second law of thermodynamics is valid only for systems which are near or in equilibrium state. For non-equilibrium systems, the laws governing system's behavior are still debatable. One of the guiding principles for these systems is the principle of maximum entropy production. It states that nonequilibrium systems behave in such a way to maximize its entropy

neg: Third law of thermodynamics shown that So the thermal expansion coefficient of all materials must go to zero at zero kelvin. J. Wilks The Third Law of Thermodynamic Third law of thermodynamics The third law of thermodynamics is sometimes stated as follows, regarding the properties of closed systems in thermodynamic equilibrium: This constant value cannot depend on any other parameters characterizing the closed system, such as pressure or applied magnetic field. At absolute zero (zero kelvin) the system must be in a state with the minimum possible energy. Entropy is related to the number of accessible microstates, and there is typically one unique state

neg: First law of thermodynamics Then the heat and work transfers may be difficult to calculate, and irreversible thermodynamics is called for. Nevertheless, the first law still holds and provides a check on the measurements and calculations of the work done irreversibly on the system, formula_33, and the heat transferred irreversibly to the system, formula_34, which belong to the same particular process defined by its particular irreversible path, formula_35, through the space of thermodynamic states. This means that the internal energy formula_8 is a function of state and that the internal energy change formula_26 between two states is a function only of the two states.

neg: History of numerical weather prediction identified seven variables that defined the state of the atmosphere at a given point: pressure, temperature, density, humidity, and the three components of the flow velocity vector. Bjerknes pointed out that equations based on mass continuity, conservation of momentum, the first and second laws of thermodynamics, and the ideal gas law could be used to estimate the state of the atmosphere in the future through numerical methods. With the exception of the second law of thermodynamics, these equations form the basis of the primitive equations used in present-day weather models. In 1922, Lewis Fry Richardson published the first attempt at

neg: First law of thermodynamics the [internal] energy per unit mass. [These authors actually use the symbols and to denote internal energy but their notation has been changed here to accord with the notation of the present article. These authors actually use the symbol to refer to total energy, including kinetic energy of bulk flow.]" This usage is followed also by other writers on non-equilibrium thermodynamics such as Lebon, Jou, and Casas-Vásquez, and de Groot and Mazur. This usage is described by Bailyn as stating the non-convective flow of internal energy, and is listed as his definition number 1, according to the first law of

neg: First law of thermodynamics diffuse with respect to one another, the system is considered to be open, the diffusive flows of the components being defined with respect to the center of mass of the system, and balancing one another as to mass transfer. Still there can be a distinction between bulk flow of internal energy and diffusive flow of internal energy in this case, because the internal energy density does not have to be constant per unit mass of material, and allowing for non-conservation of internal energy because of local conversion of kinetic energy of bulk flow to internal energy by viscosity. Gyarmati shows

neg: First law of thermodynamics later "intrinsic energy". In 1865, after some hestitation, Clausius began calling his state function formula_8 "energy". In 1882 it was named as the "internal energy" by Helmholtz. If only adiabatic processes were of interest, and heat could be ignored, the concept of internal energy would hardly arise or be needed. The relevant physics would be largely covered by the concept of potential energy, as was intended in the 1847 paper of Helmholtz on the principle of conservation of energy, though that did not deal with forces that cannot be described by a potential, and thus did not fully justify the

neg: First law of thermodynamics a fundamental postulate that goes beyond the simplest ideas of classical closed system thermodynamics; the extensivity of some variables is not obvious, and needs explicit expression; indeed one author goes so far as to say that it could be recognized as a fourth law of thermodynamics, though this is not repeated by other authors. Also of course where and denote the changes in mole number of a component substance of the system and of its surroundings respectively. This is a statement of the law of conservation of mass. A system connected to its surroundings only through contact by a single

neg: Philosophy of thermal and statistical physics Hence thermal equilibrium between systems is an equivalence relation, and this is the substance of the zeroth law of thermodynamics. According to Max Planck, who wrote an influential textbook on thermodynamics, and many other authors, this empirical principle shows that we can define the "temperature function" central to our everyday conception of heat. In simplest terms, the First Law states that the internal energy level of an isolated system is a constant. In the context of a non-isolated system, this law requires that when there is a change in energy when going from one equilibrium state to another, that change

neg: History of physics the conservation of energy. In 1788, Joseph Louis Lagrange presented Lagrange's equations of motion in "Mécanique Analytique", in which the whole of mechanics was organized around the principle of virtual work. In 1789, Antoine Lavoisier states the law of conservation of mass. The rational mechanics developed in the 18th century received a brilliant exposition in both Lagrange's 1788 work and the "Celestial Mechanics" (1799–1825) of Pierre-Simon Laplace. During the 18th century, thermodynamics was developed through the theories of weightless "imponderable fluids", such as heat ("caloric"), electricity, and phlogiston (which was rapidly overthrown as a concept following Lavoisier's identification of oxygen

neg: Volume (thermodynamics) energy in the form of work is involved. Volume is one of a pair of conjugate variables, the other being pressure. As with all conjugate pairs, the product is a form of energy. The product formula_9 is the energy lost to a system due to mechanical work. This product is one term which makes up enthalpy formula_10: where formula_12 is the internal energy of the system. The second law of thermodynamics describes constraints on the amount of useful work which can be extracted from a thermodynamic system. In thermodynamic systems where the temperature and volume are held constant, the measure

neg: Thermodynamic equations different equilibrium state. The concept which governs the path that a thermodynamic system traces in state space as it goes from one equilibrium state to another is that of entropy. The entropy is first viewed as an extensive function of all of the extensive thermodynamic parameters. If we have a thermodynamic system in equilibrium, and we release some of the extensive constraints on the system, there are many equilibrium states that it could move to consistent with the conservation of energy, volume, etc. The second law of thermodynamics specifies that the equilibrium state that it moves to is in fact