Terminology:

• Statistical Mechanics - study of how the phenomena of the macroscopic world emerge from the microscopic world
• Classical Thermodynamics (and the laws of thermodynamics)
• Entropy - measures a system's disorder
• Equilibrium - a state of physical balance
• Macroscopic and microscopic properties - properties visible to a naked eye vs. behavior of individual atoms
• The Billiard Ball Model - the first modern atomic theory, viewing atoms as tiny, solid, indivisible spheres, much like billiard balls, with no internal structure