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
Kelvin (K) – The Absolute Temperature Scale
The Kelvin scale is the absolute thermodynamic temperature scale, used primarily in scientific and engineering applications. It starts at absolute zero (0 K), the point at which all molecular motion ceases.
History of the Kelvin Scale
The Kelvin scale was developed in 1848 by Lord Kelvin (William Thomson). He proposed an absolute temperature scale where absolute zero (-273.15°C) represents the lowest possible temperature.
Usage and Applications
- Physics and Chemistry:Used in gas laws and thermodynamic calculations.
- Astronomy:Measuring temperatures of stars and celestial bodies.
- Scientific Research:Essential for precision temperature measurements.
Conversion Formulas
- To Celsius: K - 273.15
- To Fahrenheit: (K - 273.15) × 9/5 + 32
- To Rankine: K × 9/5
- To Réaumur: (K - 273.15) × 4/5