Abstract: Based on authors’ teaching experiences in college physics and solid state physics for decades and the experience of observing young teachers in college physics classrooms, several knowledge blind spots of teachers that often occur in teaching college physics due to the lack of solid state physics knowledge are summarized. The causes of conceptual ambiguity and even scientific error are precisely analyzed, and the correct understanding or expression is expounded from solid-state physics level.

Key words:  knowledge blind spots in college physics, solid state physics, longitudinal wave and shear wave velocity, birefringence, total reflection