A cryometer is a
thermometer
A thermometer is a device that temperature measurement, measures temperature or a temperature gradient (the degree of hotness or coldness of an object). A thermometer has two important elements: (1) a temperature sensor (e.g. the bulb of a merc ...
used to measure very low temperatures of objects. Ethanol-filled thermometers are used in preference to mercury for meteorological measurements of minimum temperatures and can be used down to −70 °C (-94 °F). The physical limitation of the ability of a thermometer to measure low temperature is the freezing point of the liquid used.
There are many types of devices used as cryometers:
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thermocouples
A thermocouple, also known as a "thermoelectrical thermometer", is an electrical device consisting of two dissimilar electrical conductors forming an electrical junction. A thermocouple produces a temperature-dependent voltage as a result of the ...
: these can be used down to measure about 1 K temperature.
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vapour pressure thermometer
A vapour pressure thermometer is a thermometer that uses a pressure gauge to measure the vapour pressure of a liquid.
References
Thermometers
{{thermodynamics-stub ...
s: these can be used to measure temperatures down to about 0.5K
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resistance thermometers: these can be used to measure temperatures at 0.01 K.
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melting curve thermometers: these can be used to measure temperatures between about 0.001K and 0.5K
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resistance noise thermometers: these can be used to down to about 0.001K
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magnetic thermometers: which are used at 0.001 K temperatures.
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nuclear-resonance thermometers: these are required to measure very low temperatures such as 0.0000001 K.
References
*Oxford dictionary of science, 1999, 4th edition, .
Thermometers
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