Older Units and English Units
An older unit of heat is the kilogram-calorie (Cal), originally defined as the energy required to raise the temperature of one kilogram of water by one degree Celsius, typically from 15 to 16 °C. The specific heat capacity of water on this scale would therefore be exactly 1 Cal/(°C·kg). However, due to the temperature-dependence of the specific heat, a large number of different definitions of the calorie came into being. Whilst once it was very prevalent, especially its smaller cgs variant the gram-calorie (cal), defined so that the specific heat of water would be 1 cal/(K·g), in most fields the use of the calorie is now archaic.
In the United States other units of measure for heat capacity may be quoted in disciplines such as construction, civil engineering, and chemical engineering. A still common system is the English Engineering Units in which the mass reference is pound mass and the temperature is specified in degrees Fahrenheit or Rankine. One (rare) unit of heat is the pound calorie (lb-cal), defined as the amount of heat required to raise the temperature of one pound of water by one degree Celsius. On this scale the specific heat of water would be 1 lb-cal/(K·lb). More common is the British thermal unit, the standard unit of heat in the U.S. construction industry. This is defined such that the specific heat of water is 1 BTU/(°F·lb).
Read more about this topic: Heat Capacity
Famous quotes containing the words english, older and/or units:
“There being in the make of an English mind a certain gloom and eagerness, which carries to the sad extreme; religion to fanaticism; free-thinking to atheism; liberty to rebellion.”
—George Berkeley (16851753)
“Poor Faulkner. Does he really think big emotions come from big words? He thinks I dont know the ten-dollar words. I know them all right. But there are older and simpler and better words, and those are the ones I use.”
—Ernest Hemingway (18991961)
“Even in harmonious families there is this double life: the group life, which is the one we can observe in our neighbours household, and, underneath, anothersecret and passionate and intensewhich is the real life that stamps the faces and gives character to the voices of our friends. Always in his mind each member of these social units is escaping, running away, trying to break the net which circumstances and his own affections have woven about him.”
—Willa Cather (18731947)