University of Sydney (Australia)
University of Sydney: Structure and Properties of Materials/thermal Physics
An exhaustive set of "lecture notes" on various topics in thermal physics (including thermal expansion). Explanations are well done and more interesting than most. Includes both a mathematical and conceptual treatment of topics. Humor,...
Physics Classroom
The Physics Classroom: Thermal Physics: What Is Heat?
This physics tutorial is devoted to understanding how the relative temperature of two objects affects the direction that heat is transferred between the two objects.