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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.
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.
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).
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.
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 ).
The current official highest registered air temperature on Earth is 56.7 °C (134.1 °F), recorded on 10 July 1913 at Furnace Creek Ranch, in Death Valley in the United States. [1] For ninety years, a former record that was measured in Libya had been in place, until it was decertified in 2012 based on evidence that it was an erroneous reading.
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.