Specific Heat

The specific heat of a substance is the amount of heat required to raise the temperature of a given mass of the substance one degree centigrade, compared with the amount of heat required to raise an equal mass of some standard substance one degree centigrade. Water is taken as a standard and its specific heat is 1. Compared to water specific heat of milk is 0.9454 which is lower than that of water. Thus it requires less heat to raise the temperature compared to same quantity of water. It also takes less ice to cool a certain volume of milk one degree than it does to cool the same quantity of water through one degree.

The specific heat of skim milk is lower than milk. This is due to the absence of fat from skim milk. Skim milk has a value of 0.933 to 0.954 cal g -1 C -1 . Fat has a higher specific heat of about 0.52 cal g -1 C -1 . The specific heat of milk and cream depend strongly upon the fat content.

Specific heat is measured easily with the help of a calorimeter with an electric heater. With the help of calorimeter energy used to raise the temperature can be easily measured. Specific heat of milk varies with the temperature. Specific heatof warm milk is the same as that of normal milk. This is due to the fact that fat is in the liquid state. This value is however, lower of milk as milk is cooled below 19 0 C. At this temperature some of the heat supplied to the milk system at a temperature near the melting point of the fat is used by the fat for its melting.

Specific heat of milk and milk products