temperature scales - arbitrary thermometric calibrations that serve as convenient references for temperature determination. There are two widely used thermometric scales based on the freezing and boiling point of water at a pressure of one atmosphere: the Fahrenheit (F) scale (32°= freezing, 212° = boiling) and the Celsius (C), or Centigrade, scale (0°= freezing, 100° = boiling). Additionally, there are two scales in which 0°= absolute zero, the temperature at which all molecular movement theoretically ceases: the Kelvin (°K), or Absolute (°A), scale and the Rankine (°R) scale, which are related to the Celsius and the Fahrenheit scales, respectively (0°K= -273.16°C; 0°R = -459.69°F). The four scales can be related to each other by the following formulas:
°C = 5/9 (°F-32) °K = °C + 273.16 °F = 9/5 °C+32 °R = °F + 459.69
Another scale based on the thermometric properties of water is the Reaumur scale, in which the freezing point is set at zero degrees and the boiling point at 80 degrees. This scale has only limited application.