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
Rankine (°R) – The Engineering Absolute Scale
The Rankine scale is an absolute temperature scale similar to Kelvin but based on Fahrenheit increments. It is used mainly in thermodynamic calculations, particularly in the United States.
History of the Rankine Scale
Developed by William Rankine in 1859, this scale is designed for engineering applications where Fahrenheit is commonly used.
Usage and Applications
- Thermodynamics:Used in heat and energy calculations.
- Engineering:Common in power plants and refrigeration.
Conversion Formulas
- To Celsius: (°R - 491.67) × 5/9
- To Fahrenheit: °R - 459.67
- To Kelvin: °R × 5/9
- To Réaumur: (°R - 491.67) × 4/9