Réaumur (°Re) – The Historic Scientific Scale
The Réaumur scale was once widely used in Europe, particularly in France and Germany. It is based on the freezing (0°Re) and boiling (80°Re) points of water.
History of the Réaumur Scale
Created by René Antoine Ferchault de Réaumur in 1731, the scale was primarily used in scientific and industrial applications until it was replaced by the Celsius system.
Usage and Applications
- Historic Applications:Used in 18th-19th century Europe.
- Food Industry:Some cheese-making and confectionery recipes still use Réaumur.
Conversion Formulas
- To Celsius: °Re × 5/4
- To Fahrenheit: (°Re × 9/4) + 32
- To Kelvin: (°Re × 5/4) + 273.15
- To Rankine: (°Re × 9/4) + 491.67
Fahrenheit (°F) – The American Temperature Scale
The Fahrenheit scale is widely used in the United States and some Caribbean nations. It was created by German physicist Daniel Gabriel Fahrenheit in 1724 and is based on three fixed points: 32°F (freezing point of water), 212°F (boiling point of water), and 98.6°F (average human body temperature).
History of the Fahrenheit Scale
Fahrenheit’s scale was initially based on a mixture of water, ice, and salt as the lowest calibration point. It was later refined to set 32°F as the freezing point of pure water and 212°F as its boiling point under standard atmospheric pressure.
Usage and Applications
- Weather Forecasting:Used in the U.S., Belize, and some island nations.
- Household Applications:Air conditioning, refrigeration, and oven settings.
- Medical Applications:Body temperature is often measured in Fahrenheit in the U.S.
Conversion Formulas
- To Celsius: (°F - 32) × 5/9
- To Kelvin: (°F - 32) × 5/9 + 273.15
- To Rankine: °F + 459.67
- To Réaumur: (°F - 32) × 4/9