Mechanical_Equivalent_Of_Heat

Mechanical Equivalent Of Heat Mechanical Equivalent of Heat [Abstract / Introduction] Long before physicists recognized that heat is a form of energy transfer resulting from the random microscopic motion of atoms, they defined heat in terms of the temperature changes it produces in a body. The traditional unit of heat is the calorie (cal), which is the amount of heat needed to raise the temperature of 1 g of water by 1¢ªC. The kilocalorie is 1000 cal: 1 kcal = 1000 cal. Incidentally, the calories marked on some packages of food in grocery stores are actually kilocalories, sometimes called large calories. The heat necessary to raise the temperature of 1 kg of a material by 1¢ªC is called the specific heat capacity, or the specific heat, usually designated by the symbol c. Thus, by definition, water has a specific heat of: c = 1 kcal/kg·¢ªC. Specific heat varies from substance to substance (see Appendix A, Table A4), and varies with temperature. For example, the specific heat of water varies by about 1% between 0¢ªC and 100¢ªC, reaching a minimum of 35¢ªC. This variation must be taken into account for a precise definition of the calorie: a calorie heat, temperature, water, work, specific, meh, mechanical, mass, large, equivalent, cones, j/cal, experiment, cal/g-c¢ª-1, amount, ¥Ät, metal, disk, cal, between, apparatus, two, total, submerged, stirrer, one, next, measured, known, form, force, energy, during, displacement, device