Thermodynamics is the branch of physical
science concerned with heat and its relation to
other forms of energy and work. It defines
macroscopic variables (such as temperature, entropy,
and pressure) that describe average properties of
material bodies and radiation, and explains how they
are related and by what laws they change with time.
[Wikipedia]
Statistical mechanics is a branch of
physics that applies probability theory, which
contains mathematical tools for dealing with large
populations, to the study of the thermodynamic
behavior of systems composed of a large number of
particles. ription of statistics and mechanics at
the microscopic level. [Wikipedia]
