Understanding Temperature Scales
The Celsius scale (formerly Centigrade) was developed by Swedish astronomer Anders Celsius in 1742. It defines 0°C as the freezing point of water and 100°C as the boiling point at standard atmospheric pressure. It is the primary temperature scale used in most of the world for everyday purposes, scientific work, and weather reporting.
The Fahrenheit scale was proposed by German physicist Daniel Gabriel Fahrenheit in 1724. It sets the freezing point of water at 32°F and the boiling point at 212°F. It remains in everyday use in the United States and a few other countries, though science and medicine in those countries typically use Celsius.
The Kelvin scale is the SI base unit of temperature, used primarily in science and engineering. It uses the same degree size as Celsius but starts at absolute zero — the theoretical lowest possible temperature, at which all molecular motion ceases. 0 K equals -273.15°C or -459.67°F. There are no negative values on the Kelvin scale.
The conversion formulas are: Fahrenheit to Celsius: (°F − 32) × 5/9. Celsius to Fahrenheit: (°C × 9/5) + 32. Celsius to Kelvin: °C + 273.15.