Daniel Gabriel Fahrenheit, also called Gabriel Daniel Fahrenheit (May 24, 1686 - September 16, 1736), was a physicist and an engineer, who most of his life worked in Netherlands and for whom the Fahrenheit scale of temperature is named.
Fahrenheit was born in Gdansk in Polish province of Royal Prussia where the Fahrenheits naturalised in 1650. He was the son of businessman Daniel Fahrenheit and Concordia Fahrenheit (widowed name Runge), who was the daughter of the well-known Gdansk business family Schumann. Of the five Fahrenheit children who survived childhood (2 sons, 3 daughters), Daniel was the oldest. Daniel's grandfather Reinhold Fahrenheit immigrated to Gdansk, from one of the quarters of Königsberg(Kneiphof/Knipawa) and settled there as a businessman. Research suggests that the Fahrenheit family originated in Hildesheim, although they lived in Rostock before moving to Königsberg
Upon the early death of his parents he had to take up business training. However, his interest in natural sciences caused him to take up studies and experimentation in that field. Fahrenheit's studies brought him to Amsterdam, where he gave lectures in chemistry. In 1724 he became a member of the Royal Society.
He developed precise thermometers. The Fahrenheit scale was widely used in Europe until a switch to the Celsius scale. It is still used by the general population for everyday temperature measurement in the United States.
When he first made his thermometers, he used alcohol instead of mercury. Later he used mercury, which gave better results.