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
Celsius (°C) – The Standard Temperature Scale
The Celsius scale, also known as the centigrade scale, is one of the most widely used temperature measurement systems worldwide. Named after the Swedish astronomer Anders Celsius, it is based on the freezing and boiling points of water at standard atmospheric pressure.
History of the Celsius Scale
The Celsius scale was introduced in 1742 by Anders Celsius, who initially defined it in reverse: 0°C as the boiling point and 100°C as the freezing point. This was later reversed to its modern form. The scale was designed to be practical for scientific and meteorological applications.
Usage and Applications
- Weather Forecasting:Used globally in climate and meteorology.
- Medical Applications:Human body temperature is typically around 37°C.
- Cooking and Food Industry:Oven temperatures and food safety guidelines are often in Celsius.
- Scientific Research:Used in laboratories and industries.
Conversion Formulas
- To Fahrenheit: (°C × 9/5) + 32
- To Kelvin: °C + 273.15
- To Rankine: (°C + 273.15) × 9/5
- To Réaumur: °C × 4/5