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For higher temperatures, expected values for T − T 90 are below 0.1 mK for temperatures 4.2 K – 8 K, up to 8 mK at temperatures close to 130 K, to 0.1 mK [3] at the triple point of water (273.1600 K), but rising again to 10 mK at temperatures close to 430 K, and reaching 46 mK at temperatures close to 1150 K. [9]
There are often small differences between measurements calibrated per ITS–90 and thermodynamic temperature. For instance, precise measurements show that the boiling point of VSMOW water under one standard atmosphere of pressure is actually 373.1339 K (99.9839 °C) when adhering strictly to the two-point definition of thermodynamic temperature ...
But before the redefinition, the triple point of water was exact and the Boltzmann constant had a measured value of 1.380 649 03 (51) × 10 −23 J/K, with a relative standard uncertainty of 3.7 × 10 −7. [54] Afterward, the Boltzmann constant is exact and the uncertainty is transferred to the triple point of water, which is now 273.1600(1) K ...
A thermometer calibrated to a known fixed point is accurate (i.e. gives a true reading) at that point. The invention of the technology to measure temperature led to the creation of scales of temperature. [41] In between fixed calibration points, interpolation is used, usually linear. [39]
A maximum minimum thermometer, also known as Six's thermometer, is a thermometer which registers the maximum and minimum temperatures reached over a period of time, typically 24 hours. The original design contains mercury, but solely as a way to indicate the position of a column of alcohol whose expansion indicates the temperature; it is not a ...
Another type of thermometer that is not really used much in practice, but is important from a theoretical standpoint, is the gas thermometer. Other important devices for measuring temperature include: Thermocouples; Thermistors; Resistance temperature detector (RTD) Pyrometer; Langmuir probes (for electron temperature of a plasma) Infrared ...
1612 — Santorio Sanctorius makes the first thermometer for medical use. 1617 — Giuseppe Biancani published the first clear diagram of a thermoscope 1624 — The word thermometer (in its French form) first appeared in La Récréation Mathématique by Jean Leurechon, who describes one with a scale of 8 degrees.
Thermodynamic temperature is a quantity defined in thermodynamics as distinct from kinetic theory or statistical mechanics.. Historically, thermodynamic temperature was defined by Lord Kelvin in terms of a macroscopic relation between thermodynamic work and heat transfer as defined in thermodynamics, but the kelvin was redefined by international agreement in 2019 in terms of phenomena that are ...