By : Primarinda dwita hapsari(20) . Different about alcohol as mercury thermometer 1.Advantage of alcohol thrmometer: •It can measure a low temperature,because its freezing point is low (-115˚C) •It can measure the temperture precisely, because it has large expansion coefficent
1.Advantage of alcohol thrmometer:
•It can measure a low temperature,because its freezing point is low (-115˚C)
•It can measure the temperture precisely, because it has large expansion coefficent
•Its expansion is regular
2.Disavantage of alcohol thermometer:
•It cannot measure a high temperature,because its oiling point is low (78˚C)
•It makes wet the wall of its place
•It is colourless so it must be given dyestuff in order to be visible
3.Advantage of mercury thermometer:
•It is visible, because its colour is silvery shining
•Its expansion is regular
•It does not make wet the wall of its place
•It can measure a high temperature, because its boiling point is high (356,9˚C)
•It can measure the temperature quickly and precisely
4.Disavantage of mercury thermometer:
•It cannot measure very low temperature, because its freezing point is high (-40˚C)
•Mercury is poisonous, so it is harmful if its tube is broken
•Its price is very high
This thermometer is usually used to measure a human body temperature.The tube of the thermometer is filled with mercury.The scale of the thermometer is designed from 35˚C until 42˚C ,considering the human body thermometer never lower than 35˚C and never higher than 42˚C.In clinic thermometer there is found the part of capillary tube which is narrowing.It is mean in order to mercury which has shown the numbering which has been measured , it does not decrease it self.So, the reading of body temperature can be done after the thermometer is taken from the under of tongue or arm.To return in decreasing the mercury of thermometer , it must be fluttered so the mercury level is back to the number 35 as the initial point of masurement.
This thermometer is used to measure a room temperature.Usually the thermometer is set on straight position on the wall in a room.The wall thermometer of measurement has two masurement scales, those are Celsius and Fahrenheit scales.
3)Six-Bellani maximum and minimum thermometer
This thermometer is used to measure a maximum temperature ,mainly inside glass house used for plantation as research object.The thermometer was found by James Six (1731-1793) an English scientist in the last of 18th century then it eveloped by Angelo Bellani.As shown in the figure 2.5, the thermometer consists of alcohol (now it is used creosote oil),mercury ,and small steel pointer which is equiped by light spring as its holder.