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The Measurement of Heat

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-281

2025-11-25

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The Measurement of Heat. - In order to measure the quantity of heat that is given to a certain amount of water, two things must be considered: the mass of the water and the change of the temperature. Since there are different units of mass and different thermometric scales, several thermal units are possible. The two most important are defined as follows: the quantity of heat required to raise 1 g. of water through 1° C. is called a calorie; 1 the quantity of heat required to raise 1 lb. of water through 1° F. is called a British thermal unit (B. T. U.).

1 B. T. U. = 252 calories. The measurement of the heat used in changing either the temperature or the physical condition of a body is called calorimetry.