Over the past 10 years, we have developed at University Paris-Sud a first year course on geometrical
optics centered on experimentation. In contrast with the traditional top-down learning structure
usually applied at university, in which practical sessions are often a mere verification of the laws
taught during preceding lectures, this course promotes ‘active learning’ and focuses on experiments
made by the students. Interaction among students and self questioning is strongly encouraged and
practicing comes first, before any theoretical knowledge. Through a series of concrete examples, the
present paper describes the philosophy underlying the teaching in this course. We demonstrate that
not only geometrical optics can be taught through experiments, but also that it can serve as a
useful introduction to experimental physics. Feedback over the last 10 years shows that our approach
succeeds in helping students to learn better and acquire motivation and autonomy. This approach can
e…