The formation of images in the human eye has been a focal point of interest from the past to the present. Ancient philosophers developed both intromission and extramission views on how images are formed. Today, although these views have been proven to be invalid, many students still hold similar beliefs about image formation. In this study, instructional material denoted as the dark box–cat family experiment was developed for students to test and discuss the correctness of their theories on image formation using concrete experiences.
Two key approaches on image formation arose prior to and during the period of Plato (5th century BCE). The first was the extramission theory, as described in Euclid’s Optics, which considered the eye as a light source. According to this theory, the image of an object forms in the eye with rays leaving the eye and hitting the object.1 As a proof of this...