# Réaumur to Rømer (°Ré to °Rø) Source: https://www.unitconvertercalculator.com/temperature/reaumur-to-romer/ To convert Reaumur to Romer, use the formula: Ro = Re x 21/32 + 7.5. The Reaumur scale is the historical European scale once standard in France and Germany, while the Romer scale is the early Danish scale that influenced Fahrenheit. Water freezes at 0 degrees Re (7.5 Ro) and boils at 80 degrees Re (60 Ro). ## Formula °Ré via Kelvin to °Rø ## Conversion Table | Réaumur (°Ré) | Rømer (°Rø) | |---|---| | -30 °Ré | -12.1875 °Rø | | -20 °Ré | -5.625 °Rø | | -10 °Ré | 0.9375 °Rø | | 0 °Ré | 7.5 °Rø | | 5 °Ré | 10.78125 °Rø | | 10 °Ré | 14.0625 °Rø | | 15 °Ré | 17.34375 °Rø | | 20 °Ré | 20.625 °Rø | | 25 °Ré | 23.90625 °Rø | | 30 °Ré | 27.1875 °Rø | | 40 °Ré | 33.75 °Rø | | 50 °Ré | 40.3125 °Rø | | 60 °Ré | 46.875 °Rø | | 70 °Ré | 53.4375 °Rø | | 80 °Ré | 60 °Rø | | 100 °Ré | 73.125 °Rø | | 200 °Ré | 138.75 °Rø | ## Units ### Réaumur (°Ré) A historical temperature scale where water freezes at 0 °Ré and boils at 80 °Ré. Named after René Antoine Ferchault de Réaumur. Once widely used in Europe. ### Rømer (°Rø) A temperature scale proposed by Ole Christensen Rømer in 1701. Water freezes at 7.5 °Rø and boils at 60 °Rø. It influenced Fahrenheit's scale development. ## Background The Reaumur scale was created by Rene Antoine Ferchault de Reaumur, 1730, once widespread in continental Europe. The Romer scale was created by Ole Romer, Danish astronomer, around 1701, influenced Fahrenheit. Converting between them bridges different eras and different measurement philosophies in the history of thermometry. ## Good to Know The history of temperature measurement is the history of scientific collaboration and competition across borders. The Reaumur scale (once widespread in continental Europe) and the Romer scale (influenced Fahrenheit) represent different national contributions to solving the same fundamental problem: how to assign numbers to the sensation of hot and cold. ## FAQ ### How do you convert Reaumur to Romer? Use the formula Ro = Re x 21/32 + 7.5. At the freezing point of water: 0 Re = 7.5 Ro. At the boiling point: 80 Re = 60 Ro. ### When would you need to convert Reaumur to Romer? This conversion is needed when interpreting historical scientific records, comparing temperature data across different measurement traditions, or completing engineering calculations that mix temperature scales from different national standards. ### What are the key reference points for both scales? Water freezes at 0 Re = 7.5 Ro. Water boils at 80 Re = 60 Ro. These two fixed points anchor both scales and provide easy verification of any conversion calculation. ## Non-Frequently Asked Questions ### Are Reaumur and Romer the two most European temperature scales? They are certainly the most continental. Reaumur (French, 1730) spread across France, Germany, and Russia. Romer (Danish, 1701) stayed mainly in Denmark. Together they represent the 18th-century European fever for rational measurement that eventually produced the metric system. Both scales were noble attempts; both were outcompeted by Celsius, proving that in science, second place means eventual oblivion. ### Does Reaumur-to-Romer ever appear on a physics exam? Only if the professor has a cruel sense of humor. The conversion requires knowing both scales' reference points (Reaumur: 0-80 for water; Romer: 7.5-60 for water) and the formula Ro = Re x 21/32 + 7.5. No student has ever needed this in a career. But it tests whether they can apply a conversion formula under pressure, which is arguably the real lesson. ### If 18th-century Europe held a temperature scale competition, who would judge it? The French Academy of Sciences would probably host it. Competitors would include Reaumur (French), Romer (Danish), Delisle (French, working in Russia), Newton (English), Fahrenheit (Polish-Dutch-English), and the up-and-coming Celsius (Swedish). The judges would argue for decades, which is essentially what happened historically. 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