Date of Award


Degree Name

Master of Arts



First Advisor

Dr. Alvin Rosenthal

Second Advisor

Dr. David Schuster

Third Advisor

Dr. Marcia Fetters

Access Setting

Masters Thesis-Campus Only


Vision is the primary sense by which we learn about the physical universe, and optics is thus an important subject in both physics research and education. Historical development toward our current understanding of the nature of light has yielded two useful models for explaining and predicting observations. "Geometrical optics" describes the direction of the path(s) of light, neatly depicting "ray" behavior upon encountering various kinds of obstacles or media, as in reflection and refraction. However, the visible spectrum of light is a subset of basic electromagnetic waves, and "physical optics" models the wave nature of light. While the ray model illustrates the direction of wave fronts; the more detailed wave model is necessary to explain and predict aspects of light behavior such as diffraction, interference/superposition, and color. Mastering these two models can be difficult.

This research aims to enrich qualitative understanding of student conceptions of and challenges with these topics, particularly by studying and explicating their thinking while solving problems that require one or both models of light. We analyze written work, exam problems, and details gleaned from problemsolving interviews of students in two semesters of a third year physics class on Waves and Optics. We describe and discuss key strengths and difficulties, offering specific implications for potentially enhancing effective instruction on these topics, plus some general implications for students of physics at this or any learning level.