Daniel Gabriel Fahrenheit (24 May 1686 – 16 September 1736) was a German physicist and engineer who worked most of his life in the Dutch Republic. The Fahrenheit (°F) scale of temperature is named after him.
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Biography
Fahrenheit was born in Danzig (Gdańsk) in the Polish-Lithuanian Commonwealth on 24 May 1686. The Fahrenheit family were merchants who had moved from one Hanseatic League city to the other. Fahrenheit's great-grandfather had lived in Rostock, although research suggests that the Fahrenheit family originated in Hildesheim.[1] Daniel's grandfather Reinhold Fahrenheit vom Kneiphof moved from Kneiphof (Königsberg) to Danzig and settled there as a merchant in 1650. Father Daniel Fahrenheit married Concordia (widowed name, Runge), daughter of the well-known Danzig business family of Schumann. Daniel Gabriel was the eldest of the five Fahrenheit children who survived childhood (two sons, three daughters). Upon the accidental early death of his parents, by consumption of poisonous mushrooms, Gabriel had to take up business training, as a merchant in Russia. However, his interest in natural sciences caused him to take up studies and experimentation in that field, and after travelling around, he settled 1717 in The Hague with the trade of glassblowing, making barometer, altimeter and thermometer. From 1718 onwards, he gave lectures in chemistry in Amsterdam, and became a member of the Royal Society in 1724. Fahrenheit died in The Hague.
Mercury thermometers
Fahrenheit developed precise thermometers. He filled his first thermometers with alcohol, before switching to mercury, and later developing further improvements.
Fahrenheit scale
Fahrenheit needed to associate a scale with his thermometers in order to use them to record temperature. His initial work with a temperature scale was based on three benchmarks. His low temperature mark was the coldest temperature attainable under laboratory conditions at that time: a mixture of water, ice and ammonium chloride[2]. Fahrenheit defined that as 0°F (approx. -17.8°C). Next was the freezing point of water, which he set at 32°F. Finally, he defined the human body temperature as 96°. Later, with the aid of a mercury thermometer that could measure higher temperatures, Fahrenheit adjusted his scale[3] so the high end was the boiling point of water, which he put at 212°F. With the adjustment, normal human body temperature moved to the now familiar 98°F. Fahrenheit's final temperature scale has 180 degrees between the freezing and boiling points of water. The Fahrenheit scale was widely used in Europe until the switch to the degree Celsius scale. It is still used for everyday temperature measurements by the general population in the United States and less so in the UK.
