Editing Thermometer (section)

== Indirect methods of temperature measurement ==
{{main|Temperature measurement#Technologies}}

;Thermal expansion
: Utilizing the property of [[thermal expansion]] of various [[phases of matter]].
: Pairs of solid metals with different expansion coefficients can be used for [[Bi-metallic strip#Applications|bi-metal mechanical thermometers]]. Another design using this principle is [[Breguet's thermometer]].
: Some liquids possess relatively high expansion coefficients over a useful temperature ranges thus forming the basis for an [[alcohol thermometer|alcohol]] or [[mercury thermometer|mercury]] thermometer. Alternative designs using this principle are the [[reversing thermometer]] and [[Beckmann thermometer|Beckmann differential thermometer]].
: As with liquids, gases can also be used to form a [[gas thermometer]].

;Pressure
: [[Vapour pressure thermometer]]

;Density
: [[Galileo thermometer]]<ref name=Ring2007>{{cite journal |title=The historical development of temperature measurement in medicine |author=E.F.J. Ring |journal=Infrared Physics & Technology |volume=49 |issue=3 |pages=297–301 |doi=10.1016/j.infrared.2006.06.029 |date=January 2007 |bibcode=2007InPhT..49..297R}}</ref>

;Thermochromism
: Some compounds exhibit [[thermochromism]] at distinct temperature changes. Thus by tuning the phase transition temperatures for a series of substances the temperature can be quantified in discrete increments, a form of [[digitization]]. This is the basis for a [[liquid crystal thermometer]].
:

;Band edge thermometry (BET)
: Band edge thermometry (BET) takes advantage of the temperature-dependence of the band gap of semiconductor materials to provide very precise optical (''i.e.'' non-contact) temperature measurements.<ref>{{Cite web|url=https://uwaterloo.ca/molecular-beam-epitaxy/facilities/epi-growth-and-monitoring/band-edge-thermometry|title=Band-edge thermometry|date=2014-08-19|website=Molecular Beam Epitaxy Research Group|access-date=2019-08-14}}</ref> BET systems require a specialized optical system, as well as custom data analysis software.<ref>{{Cite journal|last=Johnson|first=Shane|date=May 1998|title=In situ temperature control of molecular beam epitaxy growth using band-edge thermometry|journal=Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures|volume=16|issue=3|pages=1502–1506|doi=10.1116/1.589975|bibcode=1998JVSTB..16.1502J|hdl=2286/R.I.27894|hdl-access=free}}</ref><ref>{{Cite web|title=The truth behind today's wafer temperature methods: Band-edge thermometry vs. emissivity-corrected pyrometry|last=Wissman|first=Barry|date=June 2016|url=https://www.k-space.com/wp-content/uploads/kSA_Band_Edge_vs_ECP.pdf|access-date=December 22, 2020}}</ref>

;{{visible anchor|Blackbody radiation}}
: [[File:1024 Pyrometer-8445.jpg|thumbnail|An infrared thermometer is a kind of [[pyrometer]] ([[bolometer]]).]]All objects above [[absolute zero]] emit [[blackbody radiation]] for which the spectra is directly proportional to the temperature. This property is the basis for a [[pyrometer]] or [[infrared thermometer]] and [[thermography]]. It has the advantage of remote temperature sensing; it does not require contact or even close proximity unlike most thermometers. At higher temperatures, blackbody radiation becomes visible and is described by the [[colour temperature]]. For example a glowing heating element or an approximation of a [[star#Temperature|star's surface temperature]].

;Fluorescence
: [[Phosphor thermometry]]

;Optical absorbance spectra
: [[Fiber optical thermometer]]

;Electrical resistance
: [[Resistance thermometer]] which use materials such as [[Balco alloy]]
: [[Thermistor]]
: [[Coulomb blockade|Coulomb blockade thermometer]]

;Electrical potential
: [[Thermocouples]] are useful over a wide temperature range from cryogenic temperatures to over 1000°C, but typically have an error of ±0.5-1.5°C.
: [[Silicon bandgap temperature sensor]]s are commonly found packaged in integrated circuits with accompanying [[analog-to-digital converter|ADC]] and interface such as [[I2C|I<sup>2</sup>C]]. Typically they are specified to work within about —50 to 150°C with accuracies in the ±0.25 to 1°C range but can be improved by [[product binning|binning]].<ref>{{cite web |url=http://www.microchip.com/mymicrochip/filehandler.aspx?ddocname=en544703 |title=MCP9804: ±0.25°C Typical Accuracy Digital Temperature Sensor |date=2012 |publisher=Microchip |access-date=2017-01-03}}</ref><ref>{{cite web |url=http://www.silabs.com/Support%20Documents/TechnicalDocs/Si7050-1-3-4-5-A20.pdf |title=Si7050/1/3/4/5-A20: I2C Temperature Sensors |date=2016 |publisher=Silicon Labs |access-date=2017-01-03}}</ref>

;Electrical resonance
: [[Quartz thermometer]]

;Nuclear magnetic resonance
: [[Chemical shift]] is temperature dependent. This property is used to calibrate the thermostat of [[nuclear magnetic resonance|NMR]] probes, usually using [[methanol]] or [[ethylene glycol]].<ref>{{cite journal|last1=Findeisen|first1=M.|last2=Brand|first2=T.|last3=Berger|first3=S.|title=A1H-NMR thermometer suitable for cryoprobes|journal=Magnetic Resonance in Chemistry|date=February 2007|volume=45|issue=2|pages=175–178|doi=10.1002/mrc.1941|pmid=17154329|s2cid=43214876}}</ref><ref>{{cite book|last1=Braun|first1=Stefan Berger; Siegmar|title=200 and more NMR experiments : a practical course|date=2004|publisher=WILEY-VCH|location=Weinheim|isbn=978-3-527-31067-8|edition=[3. ed.].|url=http://ca.wiley.com/WileyCDA/WileyTitle/productCd-3527310673.html}}</ref> This can potentially be problematic for internal standards which are usually assumed to have a defined chemical shift (e.g 0 ppm for [[tetramethylsilane|TMS]]) but in fact exhibit a temperature dependence.<ref>{{cite journal|last1=Hoffman|first1=Roy E.|last2=Becker|first2=Edwin D.|title=Temperature dependence of the 1H chemical shift of tetramethylsilane in chloroform, methanol, and dimethylsulfoxide|journal=Journal of Magnetic Resonance|date=September 2005|volume=176|issue=1|pages=87–98|doi=10.1016/j.jmr.2005.05.015|pmid=15996496|bibcode=2005JMagR.176...87H|url=https://zenodo.org/record/1259141}}</ref>

;Magnetic susceptibility
: {{See also|Paramagnetism#Curie's law}}
: Above the  [[Curie temperature]], the [[magnetic susceptibility]] of a paramagnetic material exhibits an inverse temperature dependence. This phenomenon is the basis of a magnetic [[cryometer]].<ref>{{cite journal|last1=Krusius|first1=Matti|title=Magnetic thermometer|journal=AccessScience|date=2014|doi=10.1036/1097-8542.398650}}</ref><ref>{{cite book|last1=Sergatskov|first1=D. A.|title=AIP Conference Proceedings|volume=684|pages=1009–1014|chapter=New Paramagnetic Susceptibility Thermometers for Fundamental Physics Measurements|date=Oct 2003|doi=10.1063/1.1627261|chapter-url=http://authors.library.caltech.edu/27470/1/SERaipcp03.pdf|url=https://authors.library.caltech.edu/27470/1/SERaipcp03.pdf}}</ref>