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113-486: The joule ( / dʒ uː l / JOOL , or / dʒ aʊ l / JOWL ; symbol: J ) is the unit of energy in the International System of Units (SI). It is equal to the amount of work done when a force of one newton displaces a mass through a distance of one metre in the direction of that force. It is also the energy dissipated as heat when an electric current of one ampere passes through

226-470: A ⋅ m 3 =   W ⋅ s =   C ⋅ V {\displaystyle {\begin{alignedat}{3}\mathrm {J} \;&=~\mathrm {kg{\cdot }m^{2}{\cdot }s^{-2}} \\[0.7ex]&=~\mathrm {N{\cdot }m} \\[0.7ex]&=~\mathrm {Pa{\cdot }m^{3}} \\[0.7ex]&=~\mathrm {W{\cdot }s} \\[0.7ex]&=~\mathrm {C{\cdot }V} \\[0.7ex]\end{alignedat}}} One joule

339-548: A basal metabolic rate of 80 watts. For example, if our bodies run (on average) at 80 watts, then a light bulb running at 100 watts is running at 1.25 human equivalents (100 ÷ 80) i.e. 1.25 H-e. For a difficult task of only a few seconds' duration, a person can put out thousands of watts, many times the 746 watts in one official horsepower. For tasks lasting a few minutes, a fit human can generate perhaps 1,000 watts. For an activity that must be sustained for an hour, output drops to around 300; for an activity kept up all day, 150 watts

452-462: A battery (from chemical energy to electric energy ), a dam (from gravitational potential energy to kinetic energy of moving water (and the blades of a turbine ) and ultimately to electric energy through an electric generator ), and a heat engine (from heat to work). Examples of energy transformation include generating electric energy from heat energy via a steam turbine, or lifting an object against gravity using electrical energy driving

565-528: A resistance of one ohm for one second. It is named after the English physicist James Prescott Joule (1818–1889). In terms of SI base units and in terms of SI derived units with special names , the joule is defined as J =   k g ⋅ m 2 ⋅ s − 2 =   N ⋅ m =   P

678-415: A system can be subdivided and classified into potential energy , kinetic energy , or combinations of the two in various ways. Kinetic energy is determined by the movement of an object – or the composite motion of the object's components – while potential energy reflects the potential of an object to have motion, generally being based upon the object's position within a field or what is stored within

791-467: A thermodynamic system , and rest energy associated with an object's rest mass . All living organisms constantly take in and release energy. The Earth's climate and ecosystems processes are driven primarily by radiant energy from the sun . The energy industry provides the energy required for human civilization to function, which it obtains from energy resources such as fossil fuels , nuclear fuel , and renewable energy . The total energy of

904-435: A Lagrangian; for example, dissipative systems with continuous symmetries need not have a corresponding conservation law. In the context of chemistry , energy is an attribute of a substance as a consequence of its atomic, molecular, or aggregate structure. Since a chemical transformation is accompanied by a change in one or more of these kinds of structure, it is usually accompanied by a decrease, and sometimes an increase, of

1017-474: A biological cell or organelle of a biological organism. Energy used in respiration is stored in substances such as carbohydrates (including sugars), lipids , and proteins stored by cells . In human terms, the human equivalent (H-e) (Human energy conversion) indicates, for a given amount of energy expenditure, the relative quantity of energy needed for human metabolism , using as a standard an average human energy expenditure of 12,500 kJ per day and

1130-515: A bound system is discrete (a set of permitted states, each characterized by an energy level ) which results in the concept of quanta . In the solution of the Schrödinger equation for any oscillator (vibrator) and for electromagnetic waves in a vacuum, the resulting energy states are related to the frequency by Planck's relation : E = h ν {\displaystyle E=h\nu } (where h {\displaystyle h}

1243-424: A century until this was generally accepted. The modern analog of this property, kinetic energy , differs from vis viva only by a factor of two. Writing in the early 18th century, Émilie du Châtelet proposed the concept of conservation of energy in the marginalia of her French language translation of Newton's Principia Mathematica , which represented the first formulation of a conserved measurable quantity that

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1356-536: A common typographic practice among both British and U.S. publishers to capitalise significant words (and in the United States, this is often applied to headings, too). This family of typographic conventions is usually called title case . For example, R. M. Ritter's Oxford Manual of Style (2002) suggests capitalising "the first word and all nouns, pronouns, adjectives, verbs and adverbs, but generally not articles, conjunctions and short prepositions". This

1469-417: A core concept. Work , a function of energy, is force times distance. This says that the work ( W {\displaystyle W} ) is equal to the line integral of the force F along a path C ; for details see the mechanical work article. Work and thus energy is frame dependent . For example, consider a ball being hit by a bat. In the center-of-mass reference frame, the bat does no work on

1582-492: A crane motor. Lifting against gravity performs mechanical work on the object and stores gravitational potential energy in the object. If the object falls to the ground, gravity does mechanical work on the object which transforms the potential energy in the gravitational field to the kinetic energy released as heat on impact with the ground. The Sun transforms nuclear potential energy to other forms of energy; its total mass does not decrease due to that itself (since it still contains

1695-470: A descending element; also, various diacritics can add to the normal height of a letter). There is more variation in the height of the minuscules, as some of them have parts higher ( ascenders ) or lower ( descenders ) than the typical size. Normally, b, d, f, h, k, l, t are the letters with ascenders, and g, j, p, q, y are the ones with descenders. In addition, with old-style numerals still used by some traditional or classical fonts, 6 and 8 make up

1808-556: A few exceptions, like those generated by volcanic events for example. An example of a solar-mediated weather event is a hurricane, which occurs when large unstable areas of warm ocean, heated over months, suddenly give up some of their thermal energy to power a few days of violent air movement. In a slower process, radioactive decay of atoms in the core of the Earth releases heat. This thermal energy drives plate tectonics and may lift mountains, via orogenesis . This slow lifting represents

1921-484: A force vector and a displacement vector. By contrast, torque is a vector – the cross product of a force vector and a distance vector. Torque and energy are related to one another by the equation E = τ θ , {\displaystyle E=\tau \theta \,,} where E is energy, τ is (the vector magnitude of) torque, and θ is the angle swept (in radians ). Since plane angles are dimensionless, it follows that torque and energy have

2034-455: A force of one newton through a distance of one metre. However energy can also be expressed in many other units not part of the SI, such as ergs , calories , British thermal units , kilowatt-hours and kilocalories , which require a conversion factor when expressed in SI units. The SI unit of power , defined as energy per unit of time, is the watt , which is a joule per second. Thus, one joule

2147-474: A given temperature  T . This exponential dependence of a reaction rate on temperature is known as the Arrhenius equation . The activation energy necessary for a chemical reaction can be provided in the form of thermal energy. In biology , energy is an attribute of all biological systems, from the biosphere to the smallest living organism. Within an organism it is responsible for growth and development of

2260-444: A handwritten sticky note , may not bother to follow the conventions concerning capitalisation, but that is because its users usually do not expect it to be formal. Similar orthographic and graphostylistic conventions are used for emphasis or following language-specific or other rules, including: In English, a variety of case styles are used in various circumstances: In English-language publications, various conventions are used for

2373-400: A hyphen ( upper-case and lower-case  – particularly if they pre-modify another noun), or as a single word ( uppercase and lowercase ). These terms originated from the common layouts of the shallow drawers called type cases used to hold the movable type for letterpress printing . Traditionally, the capital letters were stored in a separate shallow tray or "case" that

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2486-477: A kind of gravitational potential energy storage of the thermal energy, which may later be transformed into active kinetic energy during landslides, after a triggering event. Earthquakes also release stored elastic potential energy in rocks, a store that has been produced ultimately from the same radioactive heat sources. Thus, according to present understanding, familiar events such as landslides and earthquakes release energy that has been stored as potential energy in

2599-462: A marker to indicate the beginning of a line of verse independent of any grammatical feature. In political writing, parody and satire, the unexpected emphasis afforded by otherwise ill-advised capitalisation is often used to great stylistic effect, such as in the case of George Orwell's Big Brother . Other languages vary in their use of capitals. For example, in German all nouns are capitalised (this

2712-498: A more general sense. It can also be seen as customary to capitalise any word – in some contexts even a pronoun  – referring to the deity of a monotheistic religion . Other words normally start with a lower-case letter. There are, however, situations where further capitalisation may be used to give added emphasis, for example in headings and publication titles (see below). In some traditional forms of poetry, capitalisation has conventionally been used as

2825-417: A non-standard or variant spelling. Miniscule is still less likely, however, to be used in reference to lower-case letters. The glyphs of lowercase letters can resemble smaller forms of the uppercase glyphs restricted to the baseband (e.g. "C/c" and "S/s", cf. small caps ) or can look hardly related (e.g. "D/d" and "G/g"). Here is a comparison of the upper and lower case variants of each letter included in

2938-425: A system. This property is responsible for the inertia and strength of gravitational interaction of the system ("mass manifestations"), and is also responsible for the potential ability of the system to perform work or heating ("energy manifestations"), subject to the limitations of other physical laws. In classical physics , energy is a scalar quantity, the canonical conjugate to time. In special relativity energy

3051-426: A tiny fraction of the original chemical energy is used for work : It would appear that living organisms are remarkably inefficient (in the physical sense) in their use of the energy they receive (chemical or radiant energy); most machines manage higher efficiencies. In growing organisms the energy that is converted to heat serves a vital purpose, as it allows the organism tissue to be highly ordered with regard to

3164-460: Is about the maximum. The human equivalent assists understanding of energy flows in physical and biological systems by expressing energy units in human terms: it provides a "feel" for the use of a given amount of energy. Sunlight's radiant energy is also captured by plants as chemical potential energy in photosynthesis , when carbon dioxide and water (two low-energy compounds) are converted into carbohydrates, lipids, proteins and oxygen. Release of

3277-434: Is also a scalar (although not a Lorentz scalar but a time component of the energy–momentum 4-vector ). In other words, energy is invariant with respect to rotations of space , but not invariant with respect to rotations of spacetime (= boosts ). Energy may be transformed between different forms at various efficiencies . Items that transform between these forms are called transducers . Examples of transducers include

3390-444: Is also equivalent to any of the following: The joule is named after James Prescott Joule . As with every SI unit named for a person, its symbol starts with an upper case letter (J), but when written in full, it follows the rules for capitalisation of a common noun ; i.e., joule becomes capitalised at the beginning of a sentence and in titles but is otherwise in lower case. The cgs system had been declared official in 1881, at

3503-547: Is also known as spinal case , param case , Lisp case in reference to the Lisp programming language , or dash case (or illustratively as kebab-case , looking similar to the skewer that sticks through a kebab ). If every word is capitalised, the style is known as train case ( TRAIN-CASE ). In CSS , all property names and most keyword values are primarily formatted in kebab case. "tHeqUicKBrOWnFoXJUmpsoVeRThElAzydOG" Mixed case with no semantic or syntactic significance to

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3616-409: Is an old form of emphasis , similar to the more modern practice of using a larger or boldface font for titles. The rules which prescribe which words to capitalise are not based on any grammatically inherent correct–incorrect distinction and are not universally standardised; they differ between style guides, although most style guides tend to follow a few strong conventions, as follows: Title case

3729-575: Is called the Lagrangian , after Joseph-Louis Lagrange . This formalism is as fundamental as the Hamiltonian, and both can be used to derive the equations of motion or be derived from them. It was invented in the context of classical mechanics , but is generally useful in modern physics. The Lagrangian is defined as the kinetic energy minus the potential energy. Usually, the Lagrange formalism

3842-417: Is capitalised, as are all proper nouns . Capitalisation in English, in terms of the general orthographic rules independent of context (e.g. title vs. heading vs. text), is universally standardised for formal writing. Capital letters are used as the first letter of a sentence, a proper noun, or a proper adjective . The names of the days of the week and the names of the months are also capitalised, as are

3955-424: Is capitalised. Nevertheless, the name of the unit, if spelled out, is always considered a common noun and written accordingly in lower case. For example: For the purpose of clarity, the symbol for litre can optionally be written in upper case even though the name is not derived from a proper noun. For example, "one litre" may be written as: The letter case of a prefix symbol is determined independently of

4068-473: Is defined in terms of the energy operator (Hamiltonian) as a time derivative of the wave function . The Schrödinger equation equates the energy operator to the full energy of a particle or a system. Its results can be considered as a definition of measurement of energy in quantum mechanics. The Schrödinger equation describes the space- and time-dependence of a slowly changing (non-relativistic) wave function of quantum systems. The solution of this equation for

4181-418: Is directly proportional to the mass of the body: E 0 = m 0 c 2 , {\displaystyle E_{0}=m_{0}c^{2},} where For example, consider electron – positron annihilation, in which the rest energy of these two individual particles (equivalent to their rest mass) is converted to the radiant energy of the photons produced in the process. In this system

4294-516: Is either from gravitational collapse of matter (usually molecular hydrogen) into various classes of astronomical objects (stars, black holes, etc.), or from nuclear fusion (of lighter elements, primarily hydrogen). The nuclear fusion of hydrogen in the Sun also releases another store of potential energy which was created at the time of the Big Bang . At that time, according to theory, space expanded and

4407-484: Is equal to (approximately unless otherwise stated): Units with exact equivalents in joules include: In mechanics , the concept of force (in some direction) has a close analogue in the concept of torque (about some angle): A result of this similarity is that the SI unit for torque is the newton-metre , which works out algebraically to have the same dimensions as the joule, but they are not interchangeable. The General Conference on Weights and Measures has given

4520-510: Is extremely large relative to ordinary human scales, the conversion of an everyday amount of rest mass (for example, 1 kg) from rest energy to other forms of energy (such as kinetic energy, thermal energy, or the radiant energy carried by light and other radiation) can liberate tremendous amounts of energy (~ 9 × 10 16 {\displaystyle 9\times 10^{16}} joules = 21 megatons of TNT), as can be seen in nuclear reactors and nuclear weapons. Conversely,

4633-623: Is mathematically more convenient than the Hamiltonian for non-conservative systems (such as systems with friction). Noether's theorem (1918) states that any differentiable symmetry of the action of a physical system has a corresponding conservation law. Noether's theorem has become a fundamental tool of modern theoretical physics and the calculus of variations. A generalisation of the seminal formulations on constants of motion in Lagrangian and Hamiltonian mechanics (1788 and 1833, respectively), it does not apply to systems that cannot be modeled with

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4746-402: Is no friction or other losses, the conversion of energy between these processes would be perfect, and the pendulum would continue swinging forever. Energy is also transferred from potential energy ( E p {\displaystyle E_{p}} ) to kinetic energy ( E k {\displaystyle E_{k}} ) and then back to potential energy constantly. This

4859-422: Is no technical requirement to do so – e.g., Sun Microsystems ' naming of a windowing system NeWS . Illustrative naming of the style is, naturally, random: stUdlY cAps , StUdLy CaPs , etc.. In the character sets developed for computing , each upper- and lower-case letter is encoded as a separate character. In order to enable case folding and case conversion, the software needs to link together

4972-405: Is not available. Acronyms (and particularly initialisms) are often written in all-caps , depending on various factors . Capitalisation is the writing of a word with its first letter in uppercase and the remaining letters in lowercase. Capitalisation rules vary by language and are often quite complex, but in most modern languages that have capitalisation, the first word of every sentence

5085-436: Is one watt-second, and 3600 joules equal one watt-hour. The CGS energy unit is the erg and the imperial and US customary unit is the foot pound . Other energy units such as the electronvolt , food calorie or thermodynamic kcal (based on the temperature change of water in a heating process), and BTU are used in specific areas of science and commerce. In 1843, French physicist James Prescott Joule , namesake of

5198-415: Is referred to as conservation of energy. In this isolated system , energy cannot be created or destroyed; therefore, the initial energy and the final energy will be equal to each other. This can be demonstrated by the following: The equation can then be simplified further since E p = m g h {\displaystyle E_{p}=mgh} (mass times acceleration due to gravity times

5311-853: Is removed and spaces are replaced by single underscores . Normally the letters share the same case (e.g. "UPPER_CASE_EMBEDDED_UNDERSCORE" or "lower_case_embedded_underscore") but the case can be mixed, as in OCaml variant constructors (e.g. "Upper_then_lowercase"). The style may also be called pothole case , especially in Python programming, in which this convention is often used for naming variables. Illustratively, it may be rendered snake_case , pothole_case , etc.. When all-upper-case, it may be referred to as screaming snake case (or SCREAMING_SNAKE_CASE ) or hazard case . "the-quick-brown-fox-jumps-over-the-lazy-dog" Similar to snake case, above, except hyphens rather than underscores are used to replace spaces. It

5424-572: Is sentence-style capitalisation in headlines, i.e. capitalisation follows the same rules that apply for sentences. This convention is usually called sentence case . It may also be applied to publication titles, especially in bibliographic references and library catalogues. An example of a global publisher whose English-language house style prescribes sentence-case titles and headings is the International Organization for Standardization (ISO). For publication titles it is, however,

5537-696: Is the Planck constant and ν {\displaystyle \nu } the frequency). In the case of an electromagnetic wave these energy states are called quanta of light or photons . When calculating kinetic energy ( work to accelerate a massive body from zero speed to some finite speed) relativistically – using Lorentz transformations instead of Newtonian mechanics – Einstein discovered an unexpected by-product of these calculations to be an energy term which does not vanish at zero speed. He called it rest energy : energy which every massive body must possess even when being at rest. The amount of energy

5650-418: Is the quantitative property that is transferred to a body or to a physical system , recognizable in the performance of work and in the form of heat and light . Energy is a conserved quantity —the law of conservation of energy states that energy can be converted in form, but not created or destroyed; matter and energy may also be converted to one another. The unit of measurement for energy in

5763-445: Is the main input to Earth's energy budget which accounts for its temperature and climate stability. Sunlight may be stored as gravitational potential energy after it strikes the Earth, as (for example when) water evaporates from oceans and is deposited upon mountains (where, after being released at a hydroelectric dam, it can be used to drive turbines or generators to produce electricity). Sunlight also drives most weather phenomena, save

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5876-424: Is transformed to what other kind) is often determined by entropy (equal energy spread among all available degrees of freedom ) considerations. In practice all energy transformations are permitted on a small scale, but certain larger transformations are not permitted because it is statistically unlikely that energy or matter will randomly move into more concentrated forms or smaller spaces. Energy transformations in

5989-433: Is trapped in a system with zero momentum, where it can be weighed. It is also equivalent to mass, and this mass is always associated with it. Mass is also equivalent to a certain amount of energy, and likewise always appears associated with it, as described in mass–energy equivalence . The formula E  =  mc ², derived by Albert Einstein (1905) quantifies the relationship between relativistic mass and energy within

6102-424: Is widely used in many English-language publications, especially in the United States. However, its conventions are sometimes not followed strictly – especially in informal writing. In creative typography, such as music record covers and other artistic material, all styles are commonly encountered, including all-lowercase letters and special case styles, such as studly caps (see below). For example, in

6215-519: The English alphabet (the exact representation will vary according to the typeface and font used): (Some lowercase letters have variations e.g. a/ɑ.) Typographically , the basic difference between the majuscules and minuscules is not that the majuscules are big and minuscules small, but that the majuscules generally are of uniform height (although, depending on the typeface, there may be some exceptions, particularly with Q and sometimes J having

6328-422: The International System of Units (SI) is the joule (J). Forms of energy include the kinetic energy of a moving object, the potential energy stored by an object (for instance due to its position in a field ), the elastic energy stored in a solid object, chemical energy associated with chemical reactions , the radiant energy carried by electromagnetic radiation , the internal energy contained within

6441-487: The gravitational collapse of supernovae to "store" energy in the creation of heavy isotopes (such as uranium and thorium ), and nuclear decay , a process in which energy is released that was originally stored in these heavy elements, before they were incorporated into the Solar System and the Earth. This energy is triggered and released in nuclear fission bombs or in civil nuclear power generation. Similarly, in

6554-416: The matter and antimatter (electrons and positrons) are destroyed and changed to non-matter (the photons). However, the total mass and total energy do not change during this interaction. The photons each have no rest mass but nonetheless have radiant energy which exhibits the same inertia as did the two original particles. This is a reversible process – the inverse process is called pair creation – in which

6667-526: The nuclear force or the weak force , among other examples. The word energy derives from the Ancient Greek : ἐνέργεια , romanized :  energeia , lit.   'activity, operation', which possibly appears for the first time in the work of Aristotle in the 4th century BC. In contrast to the modern definition, energeia was a qualitative philosophical concept, broad enough to include ideas such as happiness and pleasure. In

6780-520: The wordmarks of video games it is not uncommon to use stylised upper-case letters at the beginning and end of a title, with the intermediate letters in small caps or lower case (e.g., ArcaniA , ArmA , and DmC ). Single-word proper nouns are capitalised in formal written English, unless the name is intentionally stylised to break this rule (such as e e cummings , bell hooks , eden ahbez , and danah boyd ). Multi-word proper nouns include names of organisations, publications, and people. Often

6893-571: The Earth's gravitational field or elastic strain (mechanical potential energy) in rocks. Prior to this, they represent release of energy that has been stored in heavy atoms since the collapse of long-destroyed supernova stars (which created these atoms). In cosmology and astronomy the phenomena of stars , nova , supernova , quasars and gamma-ray bursts are the universe's highest-output energy transformations of matter. All stellar phenomena (including solar activity) are driven by various kinds of energy transformations. Energy in such transformations

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7006-582: The ascender set, and 3, 4, 5, 7 , and 9 the descender set. A minority of writing systems use two separate cases. Such writing systems are called bicameral scripts . These scripts include the Latin , Cyrillic , Greek , Coptic , Armenian , Glagolitic , Adlam , Warang Citi , Garay , Zaghawa , Osage , Vithkuqi , and Deseret scripts. Languages written in these scripts use letter cases as an aid to clarity. The Georgian alphabet has several variants, and there were attempts to use them as different cases, but

7119-510: The ball. But, in the reference frame of the person swinging the bat, considerable work is done on the ball. The total energy of a system is sometimes called the Hamiltonian , after William Rowan Hamilton . The classical equations of motion can be written in terms of the Hamiltonian, even for highly complex or abstract systems. These classical equations have direct analogs in nonrelativistic quantum mechanics. Another energy-related concept

7232-510: The capitalisation of the following internal letter or word, for example "Mac" in Celtic names and "Al" in Arabic names. In the International System of Units (SI), a letter usually has different meanings in upper and lower case when used as a unit symbol. Generally, unit symbols are written in lower case, but if the name of the unit is derived from a proper noun, the first letter of the symbol

7345-414: The capitalisation of words in publication titles and headlines , including chapter and section headings. The rules differ substantially between individual house styles. The convention followed by many British publishers (including scientific publishers like Nature and New Scientist , magazines like The Economist , and newspapers like The Guardian and The Times ) and many U.S. newspapers

7458-446: The case is usually known as lower camel case or dromedary case (illustratively: dromedaryCase ). This format has become popular in the branding of information technology products and services, with an initial "i" meaning " Internet " or "intelligent", as in iPod , or an initial "e" meaning "electronic", as in email (electronic mail) or e-commerce (electronic commerce). "the_quick_brown_fox_jumps_over_the_lazy_dog" Punctuation

7571-447: The case of a chemical explosion , chemical potential energy is transformed to kinetic and thermal energy in a very short time. Yet another example is that of a pendulum . At its highest points the kinetic energy is zero and the gravitational potential energy is at its maximum. At its lowest point the kinetic energy is at its maximum and is equal to the decrease in potential energy . If one (unrealistically) assumes that there

7684-965: The case of animals. The daily 1500–2000  Calories (6–8 MJ) recommended for a human adult are taken as food molecules, mostly carbohydrates and fats, of which glucose (C 6 H 12 O 6 ) and stearin (C 57 H 110 O 6 ) are convenient examples. The food molecules are oxidized to carbon dioxide and water in the mitochondria C 6 H 12 O 6 + 6 O 2 ⟶ 6 CO 2 + 6 H 2 O {\displaystyle {\ce {C6H12O6 + 6O2 -> 6CO2 + 6H2O}}} C 57 H 110 O 6 + ( 81 1 2 ) O 2 ⟶ 57 CO 2 + 55 H 2 O {\displaystyle {\ce {C57H110O6 + (81 1/2) O2 -> 57CO2 + 55H2O}}} and some of

7797-418: The code too abstract and overloaded for the common programmer to understand. Understandably then, such coding conventions are highly subjective , and can lead to rather opinionated debate, such as in the case of editor wars , or those about indent style . Capitalisation is no exception. "theQuickBrownFoxJumpsOverTheLazyDog" or "TheQuickBrownFoxJumpsOverTheLazyDog" Spaces and punctuation are removed and

7910-422: The complete conversion of matter (such as atoms) to non-matter (such as photons) is forbidden by conservation laws . Upper case Letter case is generally applied in a mixed-case fashion, with both upper and lowercase letters appearing in a given piece of text for legibility. The choice of case is often denoted by the grammar of a language or by the conventions of a particular discipline. In orthography ,

8023-451: The complex organisms can occupy ecological niches that are not available to their simpler brethren. The conversion of a portion of the chemical energy to heat at each step in a metabolic pathway is the physical reason behind the pyramid of biomass observed in ecology . As an example, to take just the first step in the food chain : of the estimated 124.7 Pg/a of carbon that is fixed by photosynthesis , 64.3 Pg/a (52%) are used for

8136-553: The concept of special relativity. In different theoretical frameworks, similar formulas were derived by J.J. Thomson (1881), Henri Poincaré (1900), Friedrich Hasenöhrl (1904) and others (see Mass–energy equivalence#History for further information). Part of the rest energy (equivalent to rest mass) of matter may be converted to other forms of energy (still exhibiting mass), but neither energy nor mass can be destroyed; rather, both remain constant during any process. However, since c 2 {\displaystyle c^{2}}

8249-404: The context of an imperative, strongly typed language. The third supports the macro facilities of LISP, and its tendency to view programs and data minimalistically, and as interchangeable. The fourth idiom needs much less syntactic sugar overall, because much of the semantics are implied, but because of its brevity and so lack of the need for capitalization or multipart words at all, might also make

8362-428: The early 19th century, and applies to any isolated system . It was argued for some years whether heat was a physical substance, dubbed the caloric , or merely a physical quantity, such as momentum . In 1845 James Prescott Joule discovered the link between mechanical work and the generation of heat. These developments led to the theory of conservation of energy, formalized largely by William Thomson ( Lord Kelvin ) as

8475-473: The energy is used to convert ADP into ATP : The rest of the chemical energy of the carbohydrate or fat are converted into heat: the ATP is used as a sort of "energy currency", and some of the chemical energy it contains is used for other metabolism when ATP reacts with OH groups and eventually splits into ADP and phosphate (at each stage of a metabolic pathway , some chemical energy is converted into heat). Only

8588-457: The energy stored during photosynthesis as heat or light may be triggered suddenly by a spark in a forest fire, or it may be made available more slowly for animal or human metabolism when organic molecules are ingested and catabolism is triggered by enzyme action. All living creatures rely on an external source of energy to be able to grow and reproduce – radiant energy from the Sun in the case of green plants and chemical energy (in some form) in

8701-438: 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 to energy, namely time. In the International System of Units (SI), the unit of energy is the joule . It is a derived unit that is equal to the energy expended, or work done, in applying

8814-436: The field itself. While these two categories are sufficient to describe all forms of energy, it is often convenient to refer to particular combinations of potential and kinetic energy as its own form. For example, the sum of translational and rotational kinetic and potential energy within a system is referred to as mechanical energy , whereas nuclear energy refers to the combined potentials within an atomic nucleus from either

8927-413: 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

9040-531: The first International Electrical Congress . The erg was adopted as its unit of energy in 1882. Wilhelm Siemens , in his inauguration speech as chairman of the British Association for the Advancement of Science (23 August 1882) first proposed the joule as unit of heat , to be derived from the electromagnetic units ampere and ohm , in cgs units equivalent to 10 erg . The naming of

9153-464: The first letter of each word is capitalised. If this includes the first letter of the first word (CamelCase, " PowerPoint ", "TheQuick...", etc.), the case is sometimes called upper camel case (or, illustratively, CamelCase ), Pascal case in reference to the Pascal programming language or bumpy case . When the first letter of the first word is lowercase (" iPod ", " eBay ", "theQuickBrownFox..."),

9266-437: The first-person pronoun "I" and the vocative particle " O ". There are a few pairs of words of different meanings whose only difference is capitalisation of the first letter. Honorifics and personal titles showing rank or prestige are capitalised when used together with the name of the person (for example, "Mr. Smith", "Bishop Gorman", "Professor Moore") or as a direct address, but normally not when used alone and in

9379-413: The height) and E k = 1 2 m v 2 {\textstyle E_{k}={\frac {1}{2}}mv^{2}} (half mass times velocity squared). Then the total amount of energy can be found by adding E p + E k = E total {\displaystyle E_{p}+E_{k}=E_{\text{total}}} . Energy gives rise to weight when it

9492-408: The late 17th century, Gottfried Leibniz proposed the idea of the Latin : vis viva , or living force, which defined as the product of the mass of an object and its velocity squared; he believed that total vis viva was conserved. To account for slowing due to friction, Leibniz theorized that thermal energy consisted of the motions of the constituent parts of matter, although it would be more than

9605-412: The lowercase when space restrictions require very small lettering. In mathematics , on the other hand, uppercase and lower case letters denote generally different mathematical objects , which may be related when the two cases of the same letter are used; for example, x may denote an element of a set X . The terms upper case and lower case may be written as two consecutive words, connected with

9718-424: The mass equivalent of an everyday amount energy is minuscule, which is why a loss of energy (loss of mass) from most systems is difficult to measure on a weighing scale, unless the energy loss is very large. Examples of large transformations between rest energy (of matter) and other forms of energy (e.g., kinetic energy into particles with rest mass) are found in nuclear physics and particle physics . Often, however,

9831-474: The metabolism of green plants, i.e. reconverted into carbon dioxide and heat. In geology , continental drift , mountain ranges , volcanoes , and earthquakes are phenomena that can be explained in terms of energy transformations in the Earth's interior, while meteorological phenomena like wind, rain, hail , snow, lightning, tornadoes and hurricanes are all a result of energy transformations in our atmosphere brought about by solar energy . Sunlight

9944-433: The modern written Georgian language does not distinguish case. All other writing systems make no distinction between majuscules and minuscules – a system called unicameral script or unicase . This includes most syllabic and other non-alphabetic scripts. In scripts with a case distinction, lowercase is generally used for the majority of text; capitals are used for capitalisation and emphasis when bold

10057-427: The molecules it is built from. The second law of thermodynamics states that energy (and matter) tends to become more evenly spread out across the universe: to concentrate energy (or matter) in one specific place, it is necessary to spread out a greater amount of energy (as heat) across the remainder of the universe ("the surroundings"). Simpler organisms can achieve higher energy efficiencies than more complex ones, but

10170-753: The name, though there is some variation in this. With personal names , this practice can vary (sometimes all words are capitalised, regardless of length or function), but is not limited to English names. Examples include the English names Tamar of Georgia and Catherine the Great , " van " and "der" in Dutch names , " von " and "zu" in German , "de", "los", and "y" in Spanish names , "de" or "d'" in French names , and "ibn" in Arabic names . Some surname prefixes also affect

10283-405: The rest mass of particles is created from the radiant energy of two (or more) annihilating photons. In general relativity, the stress–energy tensor serves as the source term for the gravitational field, in rough analogy to the way mass serves as the source term in the non-relativistic Newtonian approximation. Energy and mass are manifestations of one and the same underlying physical property of

10396-475: The rules for "title case" (described in the previous section) are applied to these names, so that non-initial articles, conjunctions, and short prepositions are lowercase, and all other words are uppercase. For example, the short preposition "of" and the article "the" are lowercase in "Steering Committee of the Finance Department". Usually only capitalised words are used to form an acronym variant of

10509-554: The same dimensions. A watt-second (symbol W s or W⋅s ) is a derived unit of energy equivalent to the joule. The watt-second is the energy equivalent to the power of one watt sustained for one second . While the watt-second is equivalent to the joule in both units and meaning, there are some contexts in which the term "watt-second" is used instead of "joule", such as in the rating of photographic electronic flash units . Energy Energy (from Ancient Greek ἐνέργεια ( enérgeia )  'activity')

10622-474: The same total energy even in different forms) but its mass does decrease when the energy escapes out to its surroundings, largely as radiant energy . There are strict limits to how efficiently heat can be converted into work in a cyclic process, e.g. in a heat engine, as described by Carnot's theorem and the second law of thermodynamics . However, some energy transformations can be quite efficient. The direction of transformations in energy (what kind of energy

10735-467: The situation is the reverse. Chemical reactions are usually not possible unless the reactants surmount an energy barrier known as the activation energy . The speed of a chemical reaction (at a given temperature  T ) is related to the activation energy  E by the Boltzmann's population factor e ; that is, the probability of a molecule to have energy greater than or equal to  E at

10848-611: The successor organisation of the International Electrical Congress) adopted the " Giorgi system", which by virtue of assuming a defined value for the magnetic constant also implied a redefinition of the joule. The Giorgi system was approved by the International Committee for Weights and Measures in 1946. The joule was now no longer defined based on electromagnetic unit, but instead as the unit of work performed by one unit of force (at

10961-459: The term majuscule an apt descriptor for what much later came to be more commonly referred to as uppercase letters. Minuscule refers to lower-case letters . The word is often spelled miniscule , by association with the unrelated word miniature and the prefix mini- . That has traditionally been regarded as a spelling mistake (since minuscule is derived from the word minus ), but is now so common that some dictionaries tend to accept it as

11074-433: The time not yet named newton ) over the distance of 1 metre . The joule was explicitly intended as the unit of energy to be used in both electromagnetic and mechanical contexts. The ratification of the definition at the ninth General Conference on Weights and Measures , in 1948, added the specification that the joule was also to be preferred as the unit of heat in the context of calorimetry , thereby officially deprecating

11187-561: The tokens, such as function and variable names start to multiply in complex software development , and there is still a need to keep the source code human-readable, Naming conventions make this possible. So for example, a function dealing with matrix multiplication might formally be called: In each case, the capitalisation or lack thereof supports a different function. In the first, FORTRAN compatibility requires case-insensitive naming and short function names. The second supports easily discernible function and argument names and types, within

11300-420: The total energy of the substances involved. Some energy may be transferred between the surroundings and the reactants in the form of heat or light; thus the products of a reaction have sometimes more but usually less energy than the reactants. A reaction is said to be exothermic or exergonic if the final state is lower on the energy scale than the initial state; in the less common case of endothermic reactions

11413-451: The unit in honour of James Prescott Joule (1818–1889), at the time retired but still living (aged 63), followed the recommendation of Siemens: Such a heat unit, if found acceptable, might with great propriety, I think, be called the Joule, after the man who has done so much to develop the dynamical theory of heat. At the second International Electrical Congress, on 31 August 1889, the joule

11526-412: The unit of energy the name joule , but has not given the unit of torque any special name, hence it is simply the newton-metre (N⋅m) – a compound name derived from its constituent parts. The use of newton-metres for torque but joules for energy is helpful to avoid misunderstandings and miscommunication. The distinction may be seen also in the fact that energy is a scalar quantity – the dot product of

11639-406: The unit of measure, discovered that the gravitational potential energy lost by a descending weight attached via a string was equal to the internal energy gained by the water through friction with the paddle. In classical mechanics, energy is a conceptually and mathematically useful property, as it is a conserved quantity . Several formulations of mechanics have been developed using energy as

11752-596: The unit symbol to which it is attached. Lower case is used for all submultiple prefix symbols and the small multiple prefix symbols up to "k" (for kilo , meaning 10 = 1000 multiplier), whereas upper case is used for larger multipliers: Some case styles are not used in standard English, but are common in computer programming , product branding , or other specialised fields. The usage derives from how programming languages are parsed , programmatically. They generally separate their syntactic tokens by simple whitespace , including space characters , tabs , and newlines . When

11865-421: The universe cooled too rapidly for hydrogen to completely fuse into heavier elements. This meant that hydrogen represents a store of potential energy that can be released by fusion. Such a fusion process is triggered by heat and pressure generated from gravitational collapse of hydrogen clouds when they produce stars, and some of the fusion energy is then transformed into sunlight. In quantum mechanics , energy

11978-401: The universe over time are characterized by various kinds of potential energy, that has been available since the Big Bang , being "released" (transformed to more active types of energy such as kinetic or radiant energy) when a triggering mechanism is available. Familiar examples of such processes include nucleosynthesis , a process ultimately using the gravitational potential energy released from

12091-416: The uppercase is reserved for special purposes, such as the first letter of a sentence or of a proper noun (called capitalisation, or capitalised words), which makes lowercase more common in regular text. In some contexts, it is conventional to use one case only. For example, engineering design drawings are typically labelled entirely in uppercase letters, which are easier to distinguish individually than

12204-417: The use of the calorie . This is the definition declared in the modern International System of Units in 1960. The definition of the joule as J = kg⋅m⋅s has remained unchanged since 1946, but the joule as a derived unit has inherited changes in the definitions of the second (in 1960 and 1967), the metre (in 1983) and the kilogram ( in 2019 ). One joule represents (approximately): 1 joule

12317-445: The use of the capitals. Sometimes only vowels are upper case, at other times upper and lower case are alternated, but often it is simply random. The name comes from the sarcastic or ironic implication that it was used in an attempt by the writer to convey their own coolness ( studliness ). It is also used to mock the violation of standard English case conventions by marketers in the naming of computer software packages, even when there

12430-409: Was distinct from momentum , and which would later be called "energy". In 1807, Thomas Young was possibly the first to use the term "energy" instead of vis viva , in its modern sense. Gustave-Gaspard Coriolis described " kinetic energy " in 1829 in its modern sense, and in 1853, William Rankine coined the term " potential energy ". The law of conservation of energy was also first postulated in

12543-578: Was located above the case that held the small letters. Majuscule ( / ˈ m æ dʒ ə s k juː l / , less commonly / m ə ˈ dʒ ʌ s k juː l / ), for palaeographers , is technically any script whose letters have very few or very short ascenders and descenders, or none at all (for example, the majuscule scripts used in the Codex Vaticanus Graecus 1209 , or the Book of Kells ). By virtue of their visual impact, this made

12656-527: Was officially adopted alongside the watt and the quadrant (later renamed to henry ). Joule died in the same year, on 11 October 1889. At the fourth congress (1893), the "international ampere" and "international ohm" were defined, with slight changes in the specifications for their measurement, with the "international joule" being the unit derived from them. In 1935, the International Electrotechnical Commission (as

12769-635: Was previously common in English as well, mainly in the 17th and 18th centuries), while in Romance and most other European languages the names of the days of the week, the names of the months, and adjectives of nationality, religion, and so on normally begin with a lower-case letter. On the other hand, in some languages it is customary to capitalise formal polite pronouns , for example De , Dem ( Danish ), Sie , Ihnen (German), and Vd or Ud (short for usted in Spanish ). Informal communication, such as texting , instant messaging or

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