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Temperature (and humidity) measurement: Difference between revisions
Temperature (and humidity) measurement (view source)
Revision as of 08:33, 11 July 2014
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An alternative way of achieving registration (preserving the value) is to have a narrow bore tube (minimum volume to be affected by expansion/contraction) with a capilary constriction separating off the bulb (that does contract but becomes isolated from the narrow bore tube permitting it to continue displaying the highest temperature). This design was used for the traditional clinical body temperature measurement. | An alternative way of achieving registration (preserving the value) is to have a narrow bore tube (minimum volume to be affected by expansion/contraction) with a capilary constriction separating off the bulb (that does contract but becomes isolated from the narrow bore tube permitting it to continue displaying the highest temperature). This design was used for the traditional clinical body temperature measurement. | ||
=Temperature Scales= | =Temperature Scales= | ||
Temperature scales use a unit called degrees apparently because some early thermonmeter designs were based on circular tubes containing liquid and had 360 equally spaced markings on them as a rough way of reporting relative 'temperatures' before any formal scales based on calibrated points was introduced. | |||
==Fahrenheit== | ==Fahrenheit== | ||
Daniel Gabriel Fahrenheit (24 May 1686 to 16 September 1736) visited Ole Remer in 1708. In 1709 Fahrenheit originated the alcohol-in-glass thermometer, and in1724 Fahrenheit developed the scale named after him based on 3 fixed points (a slightly modified version of this scale still called Fahrenheit is still used by some people in UK and is the official scale in a few countries such as the USA). | Daniel Gabriel Fahrenheit (24 May 1686 to 16 September 1736) visited Ole Remer in 1708. In 1709 Fahrenheit originated the alcohol-in-glass thermometer, and in1724 Fahrenheit developed the scale named after him based on 3 fixed points (a slightly modified version of this scale still called Fahrenheit is still used by some people in UK and is the official scale in a few countries such as the USA). | ||
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CENTIGRADE: Zero Centigrade is the freezing point of water and 100 units from there is water's boiling point at a pressure of one standard atmosphere. Jean-Pierre Christin in 1743 independently developed a temperature scale with zero for water's freezing point and 100 for water's boiling point and in May of that year he published the design of a thermometer by a craftsman in Lyon using this scale. The temperature scale 'in 100 steps' or in Latin 'centum gradus' (anglicised as Centigrade) officially ceased to exist in 1948, when the unit became degrees Celsius. Older people still use the term Centigrade sometimes in the temperature measuring context, outside the Spanish- and French-speaking world where grad applies to angular measurement (and centigrade is equivalent to 0.009 angular degrees - angular degrees is the unit where 360 is one rotation). | CENTIGRADE: Zero Centigrade is the freezing point of water and 100 units from there is water's boiling point at a pressure of one standard atmosphere. Jean-Pierre Christin in 1743 independently developed a temperature scale with zero for water's freezing point and 100 for water's boiling point and in May of that year he published the design of a thermometer by a craftsman in Lyon using this scale. The temperature scale 'in 100 steps' or in Latin 'centum gradus' (anglicised as Centigrade) officially ceased to exist in 1948, when the unit became degrees Celsius. Older people still use the term Centigrade sometimes in the temperature measuring context, outside the Spanish- and French-speaking world where grad applies to angular measurement (and centigrade is equivalent to 0.009 angular degrees - angular degrees is the unit where 360 is one rotation). | ||
=Instruments= | =Instruments= | ||
==Liquid-in-glass== | ==Liquid-in-glass== | ||