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Temperature is a physical quantity that quantitatively expresses the attribute of hotness or ... the total number of microstates in the combined system 1 + system 2 ...
History Anders Celsius's original thermometer used a reversed scale, with 100 as the freezing point and 0 as the boiling point of water.. In 1742, Swedish astronomer Anders Celsius (1701–1744) created a temperature scale that was the reverse of the scale now known as "Celsius": 0 represented the boiling point of water, while 100 represented the freezing point of water.
The highest natural ground surface temperature ever recorded may have been an alleged reading of 93.9 °C (201.0 °F) at Furnace Creek, California, United States, on 15 July 1972. [7] In 2011, a ground temperature of 84 °C (183.2 °F) was recorded in Port Sudan, Sudan. [8] The theoretical maximum possible ground surface temperature has been ...
Since 1982, STP has been defined as a temperature of 273.15 K (0 °C, 32 °F) and an absolute pressure of exactly 10 5 Pa (100 kPa, 1 bar ). NIST uses a temperature of 20 °C (293.15 K, 68 °F) and an absolute pressure of 1 atm (14.696 psi, 101.325 kPa). [3] This standard is also called normal temperature and pressure (abbreviated as NTP ).
Degree symbol. The degree symbol or degree sign, °, is a glyph or symbol that is used, among other things, to represent degrees of arc (e.g. in geographic coordinate systems ), hours (in the medical field), degrees of temperature or alcohol proof. The symbol consists of a small superscript circle.
A thermometer is a device that measures temperature (the degree of hotness or coldness of an object) or temperature gradient (the rates of change of temperature in space). A thermometer has two important elements: (1) a temperature sensor (e.g. the bulb of a mercury-in-glass thermometer or the pyrometric sensor in an infrared thermometer) in ...
Formula for the calculation of the Prandtl number of air and water. For air with a pressure of 1 bar, the Prandtl numbers in the temperature range between −100 °C and +500 °C can be calculated using the formula given below. The temperature is to be used in the unit degree Celsius.
A temperature of 0 K (−273.15 °C; −459.67 °F) is equal to 0 °R. Usage. The Rankine scale is used in engineering systems where heat computations are done using degrees Fahrenheit. The symbol for degrees Rankine is °R (or °Ra if necessary to distinguish it from the Rømer and Réaumur scales).
In fluid mechanics, the Rayleigh number ( Ra, after Lord Rayleigh [1]) for a fluid is a dimensionless number associated with buoyancy -driven flow, also known as free (or natural) convection. [2] [3] [4] It characterises the fluid's flow regime: [5] a value in a certain lower range denotes laminar flow; a value in a higher range, turbulent flow.
The "degree Kelvin" (°K) is a former name and symbol for the SI unit of temperature on the thermodynamic (absolute) temperature scale. [1] Since 1967, it has been known simply as the kelvin, with symbol K (without a degree symbol). [2] [3] [4] Degree absolute (°A) is obsolete terminology, often referring specifically to the kelvin but ...