Temperature scales
Temperature scales are standardized systems used to measure the intensity of heat, with the three most common being Celsius, Fahrenheit, and Kelvin. Other scales used throughout history include Rankine, Réaumur, Delisle, Rømer and Newton.
Developed by Anders Celsius in 1742, it is the global standard for everyday and standard scientific use. It sets 0°C as the freezing point of pure water and 100°C as the boiling point at standard atmospheric pressure.
Created by Daniel Gabriel Fahrenheit in 1724, it is primarily used in the United States. It establishes 32°F for water's freezing point and 212°F for its boiling point, dividing the range into exactly 180 equal intervals.
Proposed by Lord Kelvin in 1848, this is the international standard unit (SI) for scientific thermodynamics. It is an absolute scale starting at 0 K (absolute zero), where all molecular motion ceases, with tick marks equal in size to a Celsius degree.
Proposed by William John Macquorn Rankine in 1859, this serves as an absolute thermodynamic scale paired with Fahrenheit. It places 0°R at absolute zero, but its degree increments are identical in size to a Fahrenheit degree.
Introduced by René Antoine Ferchault de Réaumur in 1730, this scale was once popular across Europe. It defines 0°Ré as the freezing point of water and 80°Ré as the boiling point, calibrated by the expansion volume of an alcohol-water mixture.
Created by French astronomer Joseph-Nicolas Delisle in 1732, this is a unique inverted scale. It set 0°D at the boiling point of water and 150°D at the freezing point, meaning the numerical values increase as the environment gets colder
Invented by Danish astronomer Ole Christensen Rømer in 1701, this was one of the earliest calibrated scales. It set 0°Rø using a freezing brine solution and 60°Rø as the boiling point of water, capturing the melting point of pure water at exactly 7.5°Rø
Devised by Sir Isaac Newton around 1701, this scale focused on heat's physical properties. It defined 0°N as the melting point of snow and 33°N as the boiling point of water, making it a precursor to the centigrade concept.