Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measured with a thermometer . It reflects the average kinetic energy of the vibrating and colliding atoms making up a substance.
74-642: Otuoke is a suburb in Ogbia local government area of Bayelsa State in the Niger Delta region of Nigeria . Majority of its inhabitants are farmers and fishermen. Otuoke town primarily consist of three families namely; Emom, Akatim and Akiniama. The town is accessible by land and water The community houses the Federal University Otuoke which is a federal government-owned institution. This Bayelsa State , Nigeria location article
148-430: A body in a state of thermodynamic equilibrium is always positive relative to absolute zero. Besides the internationally agreed Kelvin scale, there is also a thermodynamic temperature scale , invented by Lord Kelvin , also with its numerical zero at the absolute zero of temperature, but directly relating to purely macroscopic thermodynamic concepts, including the macroscopic entropy , though microscopically referable to
222-410: A cycle of states of its working body. The engine takes in a quantity of heat Q 1 from a hot reservoir and passes out a lesser quantity of waste heat Q 2 < 0 to a cold reservoir. The net heat energy absorbed by the working body is passed, as thermodynamic work, to a work reservoir, and is considered to be the output of the engine. The cycle is imagined to run so slowly that at each point of
296-402: A fixed volume and mass of an ideal gas is directly proportional to its temperature. Some natural gases show so nearly ideal properties over suitable temperature range that they can be used for thermometry; this was important during the development of thermodynamics and is still of practical importance today. The ideal gas thermometer is, however, not theoretically perfect for thermodynamics. This
370-488: A gas can be calculated theoretically from the gas's molecular character, temperature, pressure, and the Boltzmann constant. For a gas of known molecular character and pressure, this provides a relation between temperature and the Boltzmann constant. Those quantities can be known or measured more precisely than can the thermodynamic variables that define the state of a sample of water at its triple point. Consequently, taking
444-406: A linear relation between their numerical scale readings, but it does require that the relation between their numerical readings shall be strictly monotonic . A definite sense of greater hotness can be had, independently of calorimetry , of thermodynamics, and of properties of particular materials, from Wien's displacement law of thermal radiation : the temperature of a bath of thermal radiation
518-415: A loss of heat from a closed system, without phase change, without change of volume, and without a change in external force fields acting on it, decreases its temperature. While for bodies in their own thermodynamic equilibrium states, the notion of temperature requires that all empirical thermometers must agree as to which of two bodies is the hotter or that they are at the same temperature, this requirement
592-827: A sometimes inadequate bureaucratic system. Ogbia Local Government Council - Democratic Leadership : The local government council is led by Hon. Golden Jeremiah of the People's Democratic Party (PDP), who was elected as chairman in April 2024. Responsibilities : The council functions as the third tier of governance, focusing on efficient operations across all 13 wards in Ogbia. It delivers essential services, including education, elder care, infrastructure maintenance, waste management, and community planning. Structure - The council comprises: Chairman: The chief executive overseeing overall administration. Deputy Chairman: Supports
666-462: A spatially varying local property in that body, and this is because the temperature is an intensive variable. Temperature is a measure of a quality of a state of a material. The quality may be regarded as a more abstract entity than any particular temperature scale that measures it, and is called hotness by some writers. The quality of hotness refers to the state of material only in a particular locality, and in general, apart from bodies held in
740-551: A species being all alike. It explains macroscopic phenomena through the classical mechanics of the microscopic particles. The equipartition theorem of kinetic theory asserts that each classical degree of freedom of a freely moving particle has an average kinetic energy of k B T /2 where k B denotes the Boltzmann constant . The translational motion of the particle has three degrees of freedom, so that, except at very low temperatures where quantum effects predominate,
814-415: A specific intensive variable. An example is a diathermic wall that is permeable only to heat; the intensive variable for this case is temperature. When the two bodies have been connected through the specifically permeable wall for a very long time, and have settled to a permanent steady state, the relevant intensive variables are equal in the two bodies; for a diathermal wall, this statement is sometimes called
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#1732797336548888-400: A steady state of thermodynamic equilibrium, hotness varies from place to place. It is not necessarily the case that a material in a particular place is in a state that is steady and nearly homogeneous enough to allow it to have a well-defined hotness or temperature. Hotness may be represented abstractly as a one-dimensional manifold . Every valid temperature scale has its own one-to-one map into
962-435: A system undergoing a first-order phase change such as the melting of ice, as a closed system receives heat, without a change in its volume and without a change in external force fields acting on it, its temperature rises. For a system undergoing such a phase change so slowly that departure from thermodynamic equilibrium can be neglected, its temperature remains constant as the system is supplied with latent heat . Conversely,
1036-511: Is proportional , by a universal constant, to the frequency of the maximum of its frequency spectrum ; this frequency is always positive, but can have values that tend to zero . Thermal radiation is initially defined for a cavity in thermodynamic equilibrium. These physical facts justify a mathematical statement that hotness exists on an ordered one-dimensional manifold . This is a fundamental character of temperature and thermometers for bodies in their own thermodynamic equilibrium. Except for
1110-579: Is a stub . You can help Misplaced Pages by expanding it . Ogbia Anyama Clan Oloibiri Clan Ogbia is a traditional Kingdom and Local Government Area of Bayelsa State in the Niger Delta region of Nigeria . The headquarters of both the Traditional Kingdom and Local Government is located in Ogbia Town at 4°39′00″N 6°16′00″E / 4.65000°N 6.26667°E / 4.65000; 6.26667 . Ogbia Kingdom
1184-409: Is an intensive variable because it is equal to a differential coefficient of one extensive variable with respect to another, for a given body. It thus has the dimensions of a ratio of two extensive variables. In thermodynamics, two bodies are often considered as connected by contact with a common wall, which has some specific permeability properties. Such specific permeability can be referred to
1258-518: Is arbitrary, and an alternate, less widely used absolute temperature scale exists called the Rankine scale , made to be aligned with the Fahrenheit scale as Kelvin is with Celsius. The thermodynamic definition of temperature is due to Kelvin. It is framed in terms of an idealized device called a Carnot engine , imagined to run in a fictive continuous cycle of successive processes that traverse
1332-454: Is because the entropy of an ideal gas at its absolute zero of temperature is not a positive semi-definite quantity, which puts the gas in violation of the third law of thermodynamics. In contrast to real materials, the ideal gas does not liquefy or solidify, no matter how cold it is. Alternatively thinking, the ideal gas law, refers to the limit of infinitely high temperature and zero pressure; these conditions guarantee non-interactive motions of
1406-547: Is directly proportional to the temperature of the black body; this is known as Wien's displacement law and has a theoretical explanation in Planck's law and the Bose–Einstein law . Measurement of the spectrum of noise-power produced by an electrical resistor can also provide accurate temperature measurement. The resistor has two terminals and is in effect a one-dimensional body. The Bose-Einstein law for this case indicates that
1480-489: Is disregarded. In an ideal gas , and in other theoretically understood bodies, the Kelvin temperature is defined to be proportional to the average kinetic energy of non-interactively moving microscopic particles, which can be measured by suitable techniques. The proportionality constant is a simple multiple of the Boltzmann constant. If molecules, atoms, or electrons are emitted from material and their velocities are measured,
1554-551: Is exactly equal to −273.15 °C , or −459.67 °F . Referring to the Boltzmann constant , to the Maxwell–Boltzmann distribution , and to the Boltzmann statistical mechanical definition of entropy , as distinct from the Gibbs definition, for independently moving microscopic particles, disregarding interparticle potential energy, by international agreement, a temperature scale is defined and said to be absolute because it
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#17327973365481628-472: Is in common use in the United States. Water freezes at 32 °F and boils at 212 °F at sea-level atmospheric pressure. At the absolute zero of temperature, no energy can be removed from matter as heat, a fact expressed in the third law of thermodynamics . At this temperature, matter contains no macroscopic thermal energy, but still has quantum-mechanical zero-point energy as predicted by
1702-523: Is independent of the characteristics of particular thermometric substances and thermometer mechanisms. Apart from absolute zero, it does not have a reference temperature. It is known as the Kelvin scale , widely used in science and technology. The kelvin (the unit name is spelled with a lower-case 'k') is the unit of temperature in the International System of Units (SI). The temperature of
1776-536: Is made up of four clans namely; Abureni Clan, Anyama Clan, Oloibiri Clan and Kolo Creek Clan. The people of Ogbia are part of the Ijaw (Ijo, Izon) Tribe. Ogbia has an area of 695 km and a population of over 179,926. It is well known for its historic value to the today Nigerian state economy mainstay. Crude oil was first discovered in Nigeria, at Oloibiri Town on Sunday 15 January 1956. The postal code of
1850-455: Is not safe for bodies that are in steady states though not in thermodynamic equilibrium. It can then well be that different empirical thermometers disagree about which is hotter, and if this is so, then at least one of the bodies does not have a well-defined absolute thermodynamic temperature. Nevertheless, any one given body and any one suitable empirical thermometer can still support notions of empirical, non-absolute, hotness, and temperature, for
1924-551: Is only one degree of freedom left to arbitrary choice, rather than two as in relative scales. For the Kelvin scale since May 2019, by international convention, the choice has been made to use knowledge of modes of operation of various thermometric devices, relying on microscopic kinetic theories about molecular motion. The numerical scale is settled by a conventional definition of the value of the Boltzmann constant , which relates macroscopic temperature to average microscopic kinetic energy of particles such as molecules. Its numerical value
1998-419: Is said to prevail throughout the body. It makes good sense, for example, to say of the extensive variable U , or of the extensive variable S , that it has a density per unit volume or a quantity per unit mass of the system, but it makes no sense to speak of the density of temperature per unit volume or quantity of temperature per unit mass of the system. On the other hand, it makes no sense to speak of
2072-497: The Boltzmann constant , the value of which is defined as fixed by international convention. Since May 2019, the magnitude of the kelvin is defined in relation to microscopic phenomena, characterized in terms of statistical mechanics. Previously, but since 1954, the International System of Units defined a scale and unit for the kelvin as a thermodynamic temperature , by using the reliably reproducible temperature of
2146-525: The Boltzmann constant . That constant refers to chosen kinds of motion of microscopic particles in the constitution of the body. In those kinds of motion, the particles move individually, without mutual interaction. Such motions are typically interrupted by inter-particle collisions, but for temperature measurement, the motions are chosen so that, between collisions, the non-interactive segments of their trajectories are known to be accessible to accurate measurement. For this purpose, interparticle potential energy
2220-608: The Celsius scale with the unit symbol °C (formerly called centigrade ), the Fahrenheit scale (°F), and the Kelvin scale (K), with the third being used predominantly for scientific purposes. The kelvin is one of the seven base units in the International System of Units (SI). Absolute zero , i.e., zero kelvin or −273.15 °C, is the lowest point in the thermodynamic temperature scale. Experimentally, it can be approached very closely but not actually reached, as recognized in
2294-528: The third law of thermodynamics . It would be impossible to extract energy as heat from a body at that temperature. Temperature is important in all fields of natural science , including physics , chemistry , Earth science , astronomy , medicine , biology , ecology , material science , metallurgy , mechanical engineering and geography as well as most aspects of daily life. Many physical processes are related to temperature; some of them are given below: Temperature scales need two values for definition:
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2368-602: The triple point of water as a second reference point, the first reference point being 0 K at absolute zero. Historically, the temperature of the triple point of water was defined as exactly 273.16 K. Today it is an empirically measured quantity. The freezing point of water at sea-level atmospheric pressure occurs at very close to 273.15 K ( 0 °C ). There are various kinds of temperature scale. It may be convenient to classify them as empirically and theoretically based. Empirical temperature scales are historically older, while theoretically based scales arose in
2442-459: The uncertainty principle , although this does not enter into the definition of absolute temperature. Experimentally, absolute zero can be approached only very closely; it can never be reached (the lowest temperature attained by experiment is 38 pK). Theoretically, in a body at a temperature of absolute zero, all classical motion of its particles has ceased and they are at complete rest in this classical sense. Absolute zero, defined as 0 K ,
2516-464: The zeroth law of thermodynamics says that they all measure the same quality. This means that for a body in its own state of internal thermodynamic equilibrium, every correctly calibrated thermometer, of whatever kind, that measures the temperature of the body, records one and the same temperature. For a body that is not in its own state of internal thermodynamic equilibrium, different thermometers can record different temperatures, depending respectively on
2590-688: The Azikiel Group, recognized for his efforts in boosting the local economy and development initiatives. - King A.J. Turnah of Opume: A respected traditional ruler, influencing cultural preservation and community leadership within the Ogbia people. - George Turnah: A prominent political figure This Bayelsa State , Nigeria location article is a stub . You can help Misplaced Pages by expanding it . Temperature Thermometers are calibrated in various temperature scales that historically have relied on various reference points and thermometric substances for definition. The most common scales are
2664-409: The Boltzmann constant. Taking the value of the Boltzmann constant as a primarily defined reference of exactly defined value, a measurement of the speed of sound can provide a more precise measurement of the temperature of the gas. It is possible to measure the average kinetic energy of constituent microscopic particles if they are allowed to escape from the bulk of the system, through a small hole in
2738-480: The Gibbs statistical mechanical definition of entropy for the canonical ensemble , that takes interparticle potential energy into account, as well as independent particle motion so that it can account for measurements of temperatures near absolute zero. This scale has a reference temperature at the triple point of water, the numerical value of which is defined by measurements using the aforementioned internationally agreed Kelvin scale. Many scientific measurements use
2812-409: The Kelvin temperature scale (unit symbol: K), named in honor of the physicist who first defined it . It is an absolute scale. Its numerical zero point, 0 K , is at the absolute zero of temperature. Since May 2019, the kelvin has been defined through particle kinetic theory , and statistical mechanics. In the International System of Units (SI), the magnitude of the kelvin is defined in terms of
2886-530: The Ogbia people, is Ogbia town; a town conceptualized and founded in 1972 by the Ogbia brotherhood. It also serves as the local government headquarters . The inhabitants of Ogbia land are mainly fishermen and farmers. Former Nigerian president Goodluck Ebele Jonathan was born in Otuoke , Ogbia. The first civilian governor of the old Rivers state , Chief Milford Obiene Okilo was also from Emakalakala or Amakalakala in Ogbia. According Alagoa (2009) King Amakiri,
2960-653: The area is 562. The Ogbia people, speak the Ogbia language , a unique Ijaw dialect. The Ogbia people who inhabit the Ogbia local government of Bayelsa have close kinship and language ties with the Okoroma people of Nembe local government of Bayelsa ; the Odual people of Abua /Odual local government of Rivers state as well as the Ogbogolo people of Ahoada -West in Rivers state . The present political headquarters of
3034-412: The average translational kinetic energy of a freely moving particle in a system with temperature T will be 3 k B T /2 . Molecules, such as oxygen (O 2 ), have more degrees of freedom than single spherical atoms: they undergo rotational and vibrational motions as well as translations. Heating results in an increase of temperature due to an increase in the average translational kinetic energy of
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3108-411: The body is described by stating its entropy S as a function of its internal energy U , and other state variables V , N , with S = S ( U , V , N ) , then the reciprocal of the temperature is equal to the partial derivative of the entropy with respect to the internal energy: The above definition, equation (1), of the absolute temperature, is due to Kelvin. It refers to systems closed to
3182-483: The boiling point of mercury , a mercury-in-glass thermometer is impracticable. Most materials expand with temperature increase, but some materials, such as water, contract with temperature increase over some specific range, and then they are hardly useful as thermometric materials. A material is of no use as a thermometer near one of its phase-change temperatures, for example, its boiling-point. In spite of these limitations, most generally used practical thermometers are of
3256-410: The chairman in various responsibilities. Cabinet: Appointed by the chairman, this group manages specific departments and ensures effective policy implementation. Councillors: Elected representatives who serve as a legislative body, responsible for creating and enacting local laws and policies. This dual leadership framework not only safeguards Ogbia's rich cultural heritage but also effectively meets
3330-408: The constituent molecules. The magnitude of the kelvin is now defined in terms of kinetic theory, derived from the value of the Boltzmann constant . Kinetic theory provides a microscopic account of temperature for some bodies of material, especially gases, based on macroscopic systems' being composed of many microscopic particles, such as molecules and ions of various species, the particles of
3404-501: The constituent particles of matter, so that they have a limiting specific heat of zero for zero temperature, according to the third law of thermodynamics. Nevertheless, a thermodynamic temperature does in fact have a definite numerical value that has been arbitrarily chosen by tradition and is dependent on the property of particular materials; it is simply less arbitrary than relative "degrees" scales such as Celsius and Fahrenheit . Being an absolute scale with one fixed point (zero), there
3478-410: The containing wall. The spectrum of velocities has to be measured, and the average calculated from that. It is not necessarily the case that the particles that escape and are measured have the same velocity distribution as the particles that remain in the bulk of the system, but sometimes a good sample is possible. Temperature is one of the principal quantities in the study of thermodynamics . Formerly,
3552-426: The cycle the working body is in a state of thermodynamic equilibrium. The successive processes of the cycle are thus imagined to run reversibly with no entropy production . Then the quantity of entropy taken in from the hot reservoir when the working body is heated is equal to that passed to the cold reservoir when the working body is cooled. Then the absolute or thermodynamic temperatures, T 1 and T 2 , of
3626-442: The definition just stated, was printed in 1853, a paper read in 1851. Numerical details were formerly settled by making one of the heat reservoirs a cell at the triple point of water, which was defined to have an absolute temperature of 273.16 K. Nowadays, the numerical value is instead obtained from measurement through the microscopic statistical mechanical international definition, as above. In thermodynamic terms, temperature
3700-863: The empirically based kind. Especially, it was used for calorimetry , which contributed greatly to the discovery of thermodynamics. Nevertheless, empirical thermometry has serious drawbacks when judged as a basis for theoretical physics. Empirically based thermometers, beyond their base as simple direct measurements of ordinary physical properties of thermometric materials, can be re-calibrated, by use of theoretical physical reasoning, and this can extend their range of adequacy. Theoretically based temperature scales are based directly on theoretical arguments, especially those of kinetic theory and thermodynamics. They are more or less ideally realized in practically feasible physical devices and materials. Theoretically based temperature scales are used to provide calibrating standards for practical empirically based thermometers. In physics,
3774-466: The first king of modern Kalabari kingdom (1669-1757) came from Emakalakala in Ogbia. The leadership structure of Ogbia exemplifies a successful integration of traditional and democratic governance, ensuring both cultural preservation and effective administration. Ogbia Kingdom - Traditional Leadership : The Ogbia Kingdom is headed by an Obanobhan (King), currently His Royal Majesty King Dumaro Charles Owaba, Obanobhan III. The kingship rotates among
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#17327973365483848-455: The formulation of the first law of thermodynamics. Carnot had no sound understanding of heat and no specific concept of entropy. He wrote of 'caloric' and said that all the caloric that passed from the hot reservoir was passed into the cold reservoir. Kelvin wrote in his 1848 paper that his scale was absolute in the sense that it was defined "independently of the properties of any particular kind of matter". His definitive publication, which sets out
3922-467: The four clans, promoting inclusivity and representation, with the next monarch expected from the Kolo Creek clan. The Obanobhan fulfills several important roles, such as mediating between the community and the state, preserving Ogbia's cultural traditions, fostering national identity, driving both infrastructure and human capital development, resolving minor disputes, and acting as a stabilizing force in
3996-494: The hotness manifold. When two systems in thermal contact are at the same temperature no heat transfers between them. When a temperature difference does exist heat flows spontaneously from the warmer system to the colder system until they are in thermal equilibrium . Such heat transfer occurs by conduction or by thermal radiation. Experimental physicists, for example Galileo and Newton , found that there are indefinitely many empirical temperature scales . Nevertheless,
4070-419: The internal energy at a point, while when local thermodynamic equilibrium prevails, it makes good sense to speak of the temperature at a point. Consequently, the temperature can vary from point to point in a medium that is not in global thermodynamic equilibrium, but in which there is local thermodynamic equilibrium. Thus, when local thermodynamic equilibrium prevails in a body, the temperature can be regarded as
4144-409: The internationally agreed conventional temperature scale is called the Kelvin scale. It is calibrated through the internationally agreed and prescribed value of the Boltzmann constant, referring to motions of microscopic particles, such as atoms, molecules, and electrons, constituent in the body whose temperature is to be measured. In contrast with the thermodynamic temperature scale invented by Kelvin,
4218-428: The magnitude of the kelvin was defined in thermodynamic terms, but nowadays, as mentioned above, it is defined in terms of kinetic theory. The thermodynamic temperature is said to be absolute for two reasons. One is that its formal character is independent of the properties of particular materials. The other reason is that its zero is, in a sense, absolute, in that it indicates absence of microscopic classical motion of
4292-419: The mechanisms of operation of the thermometers. For experimental physics, hotness means that, when comparing any two given bodies in their respective separate thermodynamic equilibria , any two suitably given empirical thermometers with numerical scale readings will agree as to which is the hotter of the two given bodies, or that they have the same temperature. This does not require the two thermometers to have
4366-444: The middle of the nineteenth century. Empirically based temperature scales rely directly on measurements of simple macroscopic physical properties of materials. For example, the length of a column of mercury, confined in a glass-walled capillary tube, is dependent largely on temperature and is the basis of the very useful mercury-in-glass thermometer. Such scales are valid only within convenient ranges of temperature. For example, above
4440-435: The molecules. Heating will also cause, through equipartitioning , the energy associated with vibrational and rotational modes to increase. Thus a diatomic gas will require more energy input to increase its temperature by a certain amount, i.e. it will have a greater heat capacity than a monatomic gas. As noted above, the speed of sound in a gas can be calculated from the gas's molecular character, temperature, pressure, and
4514-400: The noise-power is directly proportional to the temperature of the resistor and to the value of its resistance and to the noise bandwidth. In a given frequency band, the noise-power has equal contributions from every frequency and is called Johnson noise . If the value of the resistance is known then the temperature can be found. Historically, till May 2019, the definition of the Kelvin scale
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#17327973365484588-423: The point chosen as zero degrees and the magnitudes of the incremental unit of temperature. The Celsius scale (°C) is used for common temperature measurements in most of the world. It is an empirical scale that developed historically, which led to its zero point 0 °C being defined as the freezing point of water , and 100 °C as the boiling point of water, both at atmospheric pressure at sea level. It
4662-510: The practical governance needs of the community. In Ogbia, the year-round weather is stifling, with the wet season being warm and cloudy and the dry season being hot and largely clear. The average annual temperature is between 72°F and 87°F; it rarely falls below 64°F or rises beyond 90°F. Ogbia Communities/Town' Ogbia is indeed home to several notable figures who have made significant contributions to Nigeria. These individuals have greatly influenced politics, governance, and development in
4736-454: The presently conventional Kelvin temperature is not defined through comparison with the temperature of a reference state of a standard body, nor in terms of macroscopic thermodynamics. Apart from the absolute zero of temperature, the Kelvin temperature of a body in a state of internal thermodynamic equilibrium is defined by measurements of suitably chosen of its physical properties, such as have precisely known theoretical explanations in terms of
4810-551: The region: - His Excellency, Dr. Goodluck Jonathan, GCFR, GCON : The 14th President of Nigeria, who served from 2010 to 2015, is well-known for his leadership during a transformative period in the country. - Chief Melford Okilo : The first Governor of Rivers State, who played a crucial role in the state’s early development and governance. - Senator Clever Ikisikpo : A prominent political figure, contributing to legislative processes and regional advocacy. - Dr. Eruani Azibapu Godbless : A former Bayelsa Commissioner and Chairman of
4884-403: The reservoirs are defined such that The zeroth law of thermodynamics allows this definition to be used to measure the absolute or thermodynamic temperature of an arbitrary body of interest, by making the other heat reservoir have the same temperature as the body of interest. Kelvin's original work postulating absolute temperature was published in 1848. It was based on the work of Carnot, before
4958-453: The spectrum of their velocities often nearly obeys a theoretical law called the Maxwell–Boltzmann distribution , which gives a well-founded measurement of temperatures for which the law holds. There have not yet been successful experiments of this same kind that directly use the Fermi–Dirac distribution for thermometry, but perhaps that will be achieved in the future. The speed of sound in
5032-407: The study by methods of classical irreversible thermodynamics, a body is usually spatially and temporally divided conceptually into 'cells' of small size. If classical thermodynamic equilibrium conditions for matter are fulfilled to good approximation in such a 'cell', then it is homogeneous and a temperature exists for it. If this is so for every 'cell' of the body, then local thermodynamic equilibrium
5106-428: The transfer of matter and has a special emphasis on directly experimental procedures. A presentation of thermodynamics by Gibbs starts at a more abstract level and deals with systems open to the transfer of matter; in this development of thermodynamics, the equations (2) and (3) above are actually alternative definitions of temperature. Real-world bodies are often not in thermodynamic equilibrium and not homogeneous. For
5180-428: The value of the Boltzmann constant as a primarily defined reference of exactly defined value, a measurement of the speed of sound can provide a more precise measurement of the temperature of the gas. Measurement of the spectrum of electromagnetic radiation from an ideal three-dimensional black body can provide an accurate temperature measurement because the frequency of maximum spectral radiance of black-body radiation
5254-411: The zeroth law of thermodynamics. In particular, when the body is described by stating its internal energy U , an extensive variable, as a function of its entropy S , also an extensive variable, and other state variables V , N , with U = U ( S , V , N ), then the temperature is equal to the partial derivative of the internal energy with respect to the entropy: Likewise, when
5328-432: Was called a centigrade scale because of the 100-degree interval. Since the standardization of the kelvin in the International System of Units, it has subsequently been redefined in terms of the equivalent fixing points on the Kelvin scale, so that a temperature increment of one degree Celsius is the same as an increment of one kelvin, though numerically the scales differ by an exact offset of 273.15. The Fahrenheit scale
5402-421: Was defined to be exactly 273.16 K . Since May 2019, that value has not been fixed by definition but is to be measured through microscopic phenomena, involving the Boltzmann constant, as described above. The microscopic statistical mechanical definition does not have a reference temperature. A material on which a macroscopically defined temperature scale may be based is the ideal gas . The pressure exerted by
5476-411: Was that invented by Kelvin, based on a ratio of quantities of energy in processes in an ideal Carnot engine, entirely in terms of macroscopic thermodynamics. That Carnot engine was to work between two temperatures, that of the body whose temperature was to be measured, and a reference, that of a body at the temperature of the triple point of water. Then the reference temperature, that of the triple point,
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