Scale of temperature the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale two years before his death. The degree Celsius (°C) can refer to a specific temperature on the Celsius scale as well as a unit to indicate a temperature "interval "(a difference between two temperatures or an uncertainty). From 1744 until 1954, 0 °C was defined as the freezing point of water and 100 °C was defined as the boiling point of water, both at a pressure of one standard atmosphere. Although these defining correlations are commonly taught in schools today, by international agreement the unit "degree Celsius" and
Temperature which implies Since the first function is independent of "T", this temperature must cancel on the right side, meaning "f"("T","T") is of the form "g"("T")/"g"("T") (i.e. "f"("T","T") = "f"("T","T")"f"("T","T") = "g"("T")/"g"("T")· "g"("T")/"g"("T") = "g"("T")/"g"("T")), where "g" is a function of a single temperature. A temperature scale can now be chosen with the property that Substituting (4) back into (2) gives a relationship for the efficiency in terms of temperature: For "T" = 0 K the efficiency is 100% and that efficiency becomes greater than 100% below 0 K. Since an efficiency greater than 100% violates the first law of thermodynamics,