Temperature scale

ORDERBY-NAME:  Temperature scale

OTHER-NAME:

DATE INVENTED/BEGAN:  1701

PLACE INVENTED/BEGAN:  Copenhagen, Denmark

DATE ENDED:

PLACE ENDED:

CATEGORY: Technology

DISCIPLINE: Precision instrumentation

ASSESSMENT: The temperature scale was developed early in the modern world and has been in successful common use ever since.

LANGUAGE:  Danish; German, Swedish

DETAILS:  In 1701 Danish astronomer Ole <developed by> Romer* called the boiling point of water 60 degrees and saw that freezing happened at about  an eight of that figure (7.5). 

In 1708 German physicist Gabriel <developed by> Fahrenheit* made the system more accurate by multiplying Roemer’s numbers by four, so freezing was now 30 and boiling 240 (later refined to 32 and 212). 

In 1742 Swedish astronomer Andreas <developed by> Celsius* attempted further refinement when he placed a thin cylinder of glass filled with mercury into ice made of pure water and at the moment when the ice melted and the mercury level stopped rising he marked the level on the cylinder.  Then he did the same thing above water as it reached boiling point.  When the mercury in the cylinder, suspended in the boiling water vapor, stopped rising, he marked the mercury level.  He called these two points ‘0’ and ‘100’ and then divided the cylinder up into 100 equally-spaced marks.  He called this system (of one hundred degrees):  ‘centigrade.’ 

Celsius’ system has been adopted by most countries and by the scientific community.

ONELINER:  Temperature scale

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