I enjoyed reading the “Little Gems” column on “A Glass of Wine a Day Does Not Keep Optics Away” in the November 2013 issue of TPT (p. 506). A very similar activity can be achieved with a good friend, a dark room, and a candle. With the candle lit in front of you, tell your friend to come close and “look into my eyes….” At this point you better tell your friend that you are doing a physics experiment with Purkinje images. (You can read much more about them on Wikipedia).
The first Purkinje image (I) is a reflection from the front surface (anterior) of the cornea, and the second (II) is a reflection from the inner surface (posterior) of the cornea. Image (II) is very difficult to see because of the thinness of the cornea. Image three (III) is a reflection from the front surface (anterior) of the lens,...