What is the importance of the concept of continuum in engineering thermodynamics.

Sol: Tough the simplification of matter into atoms, electrons, molecules, and so on, is very complex a picture for so many problems of thermodynamics. Thermodynamics forms no hypotheses about the structure of the matter of the system. The volumes of the system referred are very large compared to molecular dimensions. The system is considered as a continuum. The system is supposed to consist of continuous distribution of matter.

There are no cavities and voids. The pressure, temperature, density and other properties are the average values of action of several molecules and atoms. Such type of idealization is must for solving most problems. The laws and issues of thermodynamics are independent of structure of matter. As per to this concept there is minimum limit of volume up-to which the property remain continuum. Lower than this volume, there is sudden change in the value of the property. Such type of a region is known as region of discrete particles and the region for which the property are maintain is known as region of continuum. The limiting volume up to which continuum properties are kept is called continuum limit.