Optics Demonstration with Student Eyeglasses Using the Inquiry Method

A favorite qualitative optics demonstration I perform in introductory physics classes makes use of students' eyeglasses to introduce converging and diverging lenses.1 Taking on the persona of a magician, I walk to the back of the classroom and approach a student wearing glasses. The top part of Fig. 1 shows a glasses-wearing student who is farsighted in her left eye and has a slight astigmatism in her right eye.