Daniel Gabriel Fahrenheit, Polish-Dutch physicist and engineer, invented the thermometer (b. 1686)

Daniel Gabriel Fahrenheit FRS (; German: [ˈfaːʁn̩haɪt]; 24 May 1686 – 16 September 1736) was a physicist, inventor, and scientific instrument maker. Fahrenheit was born in Danzig (Gdańsk), then a predominantly German-speaking city in the Pomeranian Voivodeship of the Polish–Lithuanian Commonwealth. He later moved to the Dutch Republic at age 15, where he spent the rest of his life (1701–1736) and was one of the notable figures in the Golden Age of Dutch science and technology.

A pioneer of exact thermometry, he helped lay the foundations for the era of precision thermometry by inventing the mercury-in-glass thermometer (first widely used, practical, accurate thermometer) and Fahrenheit scale (first standardized temperature scale to be widely used). In other words, Fahrenheit's inventions ushered in the first revolution in the history of thermometry (branch of physics concerned with methods of temperature measurement). From the early 1710s until the beginnings of the electronic era, mercury-in-glass thermometers were among the most reliable and accurate thermometers ever invented.