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
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