Thermal capacity is the heat required to raise a body one unit or degree of temperature. Thermal capacity and heat capacity are synonymous.

Specific heat is the ratio of the thermal capacity of the substance to that of water (at 15 degree C). Therefore, thermal capacity is numerically equal to specific heat. Specific heat is a function of fluid structure and density. In hydrodynamic lubrication , specific heat is used in the calculation of heat transfer, temperature rise, and other thermal factors in an oil film

Therefore, more heat is required to raise the temperature of 1 kilogram of water and oil than is required for steel.

Specific heat is measured using ASTM D 3947. A sample is introduced into a differential scanning calorimeter by means of a hermetically sealed sample cell. The cell is placed on a thermocouple in a controlled environment programmed to increase temperature at a specific rate. This allows the calculation of the specific heat of the oil.