• Matter is made up of atoms that are widely spaced in the gas phase. Yet it is very convenient to disregard the atomic
nature of a substance and view it as a continuous, homogeneous matter with no holes, that is, a continuum.
• The continuum idealization allows us to treat properties as point functions and toassume the properties vary continually
in space with no jump discontinuities.
• This idealization is valid as long as the size of the system we deal with is large relative to the space between themolecules.
• This is the case in practically all problems.
• In this text we will limit our consideration to substances