Convert Reaumur (°r) to Triple Point of Water (TPW) instantly.
About these units
Reaumur (°r)
The Réaumur scale, created by René Antoine Ferchault de Réaumur in 1730, was once a major temperature scale in Europe, particularly in France, Germany, Russia, and parts of Italy. It sets the freezing point of water at 0°r and the boiling point at 80°r, giving it eighty divisions between these points. Réaumur's scale was historically used in cheese-making, brewing, confectionery, textile production, and early scientific experiments. Many recipes and industrial methods from the 18th and 19th centuries reference it. The scale's smaller numeric range made it easy to work with, though it offered less granularity than Celsius. Eventually, the Celsius scale replaced Réaumur almost everywhere due to metric standardization. However, the Réaumur scale's legacy persists in historical documents, culinary traditions, and scientific literature from the Enlightenment era, where it formed a cornerstone of early temperature standardization.
Triple Point of Water (TPW)
The Triple Point of Water (TPW) is not a temperature scale but a defining thermodynamic condition where water exists simultaneously as solid, liquid, and vapor. This state occurs at a very precise temperature: 273.16 K (0.01°C) under a pressure of 611.657 pascals. The TPW was historically crucial because the kelvin was directly defined using this temperature. Prior to the 2019 SI redefinition, the triple point of water served as the anchor for the absolute temperature scale and was used to calibrate thermometers worldwide. This made high-precision thermometry simpler, as laboratories could reproduce the TPW by using sealed cells filled with highly pure water. Even though the kelvin is now defined through Boltzmann's constant, the TPW remains essential in metrology because it is one of the most reproducible physical phenomena known. Standard cells are still used for calibrations, research, and quality control in temperature-sensitive industries. The TPW embodies the elegance of thermodynamics: a single point where phase equilibrium meets the foundations of measurement.