The systems we can directly see are composed of huge numbers of particles.
So, the properties of these systems are obtained as statistical averages of the effects of
their particles. This casts a conceptual bridge between the macroscopic world wherein
we observe systems with their overall properties and the microscopic world where
particles with their own properties dominate the scene. Statistical mechanics shows that
the former world is determined by what happens in the latter, and this approach
provides a better, finer understanding of what’s going on at the macroscopic level and
why.
Keywords: Accessible microstates, Boltzmann entropy, Constraints,
Equilibration, Gibbs entropy, Inertness, Macroscopically stable equilibrium,
Maximum entropy, Maxwell-Boltzmann distribution, Microstates,
Microscopically dynamic equilibrium, Phase space, Second law, Spreading
function, Stability, Statistical mechanics, Thermodynamic ensemble, Trajectory.