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Scales Of Temperature
Scale of temperature is a methodology of calibrating the physical quantity temperature in metrology. Empirical scales measure temperature in relation to convenient and stable parameters or reference points, such as the freezing and boiling point of water. Absolute temperature is based on thermodynamic principles: using the lowest possible temperature as the zero point, and selecting a convenient incremental unit. Celsius, Kelvin, and Fahrenheit are common temperature scales. Other scales used throughout history include Rankine, Rømer, Newton, Delisle, Réaumur, Gas mark, Leiden, and Wedgwood. Technical definition The zeroth law of thermodynamics describes thermal equilibrium between thermodynamic systems in form of an equivalence relation. Accordingly, the set of all thermal systems may be divided into a quotient set of equivalence classes, denoted as M, where any element of M collects all systems that are in thermal equilibrium with one another. If the set M has cardin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physical Quantity
A physical quantity (or simply quantity) is a property of a material or system that can be Quantification (science), quantified by measurement. A physical quantity can be expressed as a ''value'', which is the algebraic multiplication of a ''numerical value'' and a ''unit of measurement''. For example, the physical quantity mass, symbol ''m'', can be quantified as ''m'n''kg, where ''n'' is the numerical value and kg is the unit symbol (for kilogram). Quantities that are vectors have, besides numerical value and unit, direction or orientation in space. Components Following ISO 80000-1, any value or Magnitude (mathematics), magnitude of a physical quantity is expressed as a comparison to a unit of that quantity. The ''value'' of a physical quantity ''Z'' is expressed as the product of a ''numerical value'' (a pure number) and a unit [''Z'']: :Z = \ \times [Z] For example, let Z be "2 metres"; then, \ = 2 is the numerical value and [Z] = \mathrm is the unit. Conversely, the nu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gas Mark
The gas mark is a temperature scale used on gas ovens and cookers in the United Kingdom, Republic of Ireland, Ireland and some Commonwealth of Nations countries. History Early gas ovens had no thermostats and it was up to the cook to continually adjust a manual valve to keep the oven at the desired temperature. For this and other reasons gas cookers were not popular; most users preferred the coal-fired open kitchen range. The breakthrough came in the 1920s when a manufacturer introduced the Regulo. REGULO was originally a proprietary name chosen by Radiation Ltd. to denote their new automatic temperature controller. In a series of press advertisements published on 13 May 1923 to announce their "New World" cooker it was stated that, by simply setting a pointer, the oven would go to the desired temperature and stay there without requiring further attention. The current (2025) online edition of the ''Oxford English Dictionary'' indicates that Radiation Ltd. applied to register ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |