The German instrument maker Gabriel Fahrenheit made the first reliable thermometers, and the temperature scale he created is named after him.

Early life

Born in Danzig, Germany, on May 14, 1686, Gabriel Daniel Fahrenheit was one of Daniel and Concordia Schumann Fahrenheit's five children. His father was a wealthy merchant. Both his parents died on the same day, August 14, 1701, and he was then sent to Amsterdam, the Netherlands, to work for and learn from a shopkeeper. After completing a term of four years there, Fahrenheit became interested in making scientific instruments. Although he lived in Amsterdam most of his life, he traveled widely to observe the work of scientists and makers of instruments in other areas. He spent considerable time in England, where he became a member of the Royal Society (Great Britain's oldest organization of scientists).

Creation of thermometers

Fahrenheit completed his first two thermometers by 1714. They contained alcohol and agreed exactly in their readings. The scale that was to bear Fahrenheit's name had not yet been made standard, and many different scales were tried before he settled on one. He soon decided to replace the alcohol with mercury and completed a series of investigations based on the work of Danish astronomer Olaus Roemer. In these investigations he determined the boiling point of water and other liquids and studied the expansion (increase in volume) properties of mercury. These experiments led to the discovery that the boiling point of water varies with changes in the pressure of the atmosphere. Fahrenheit also discovered the method of supercooling water—that is, cooling water to below its normal freezing point without it becoming ice.

Taking all of these factors into consideration, Fahrenheit began to doubt the reliability of the freezing and boiling points of water. He finally settled on a temperature scale ranging from 0 to 212