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Structure of Laboratory Thermometer

Physics

definition

Construction and working of types of thermometer

Laboratory thermometers:They are used to measure temperatures or temperaturechangeswithahighdegreeofprecision.Theyaremadeofmetalorglassandstrengthenedthroughprocessessuchasthermaltemperingorannealing.For example, liquid-in-glassthermometersaremadeofsealedglassandcontainafluid,usuallymercuryorredcolouredalcohol,whosevolumechangesrelativelytoitstemperature.Bimetallicstripthermometersincludetwodifferentmetalsthatarebondedtogetherandexpandatdifferentratesastheywarmup.Longbimetallicstripsarewoundintoacoilandusedwithadial.
Clinicalthermometer: It isdesigned forclinicaluse inhumansoranimals.Itismadeofafinecapillarywithabulbfilledwithmercuryatoneend.Nearthebulb,ithasanarrowbendknownasconstriction.Beforeuse,thethermometerisjerkedsothatthemercuryflowsbackintothebulb.

definition

Importance of Laboratory Thermometer

The range of a laboratory thermometer is generally from 10C to 110C. Hence it is not used for measuring body temperature.
Importance of laboratory thermometer:
  • Laboratory thermometers are designed small to make it potable.
  • Bulb of laboratory thermometer is usually larger than its bore in order to contain more liquid, to improve its sensitivity.That's why its more precise as even a small change in temperature will make the liquid to rise in the capillary tube.