Seeing the Light: A Classroom-Sized Pinhole Camera Demonstration for Teaching Vision

We describe a classroom-sized pinhole camera demonstration (camera obscura) designed to enhance students' learning of the visual system. The demonstration consists of a suspended rear-projection screen onto which the outside environment projects images through a small hole in a classroom window. Students can observe these images in a darkened classroom. Instructors can demonstrate the function of the lens and pupil and the structural basis for nearsightedness and farsightedness. Students who saw the demonstration as part of a lecture on the visual system learned more (i.e., showed greater performance gains from pretest to posttest) than a comparable group of students who received the lecture only. Students reacted favorably to the demonstration. These data suggest that incorporating the demonstration into class presentations on vision can improve student learning.