What's strange to me, is that my interpretation of the results of such an experiment wouldn't even lead to your professor's conclusion. The takeaway being the fallibility of sensory perception, where I might then prompt the class for a discussion of their intuitive refutations of empiricism before diving into the literature.
Unfortunately, being a philosophy major myself, I know all too well that a crap teacher can totally ruin a philosophy topic (let alone a topic of any subject). From my 4 years in philosophy classes of varying levels of difficulty, the common denominator between a fruitful time spent in class has been the willingness of the professor to engage with their students. Whether it's logic, metaphysics, epistemology, ontology, &c, the principal property of a quality professor is his/her dialectical ability.
Hell, that's how philosophy & theology was taught in the first universities! The professor would profess and then the students would engage their master in the subject at hand.