According to several studies, the three levels of representation in chemistry are the fundamental aspects of effective learning and understanding of chemistry. In this study, we aim to illustrate how students identify changes in the matter using eye-tracking and verbalizations. Five students observed chemical and physical phenomena depicted by using the three representational levels under eye-tracking monitoring. This allows making inferences about which representation received students' attention for the longest time. In order to enrich this illustrative experiment, data were triangulated with think-aloud techniques and researchers' observations during the procedure. Our results suggest that eye-tracking experiments may provide some relevant insights into students' cognition regarding representational levels. The multiple case study presented hereby pointed out that the levels observed for the longest time were the macro and the submicro levels, although only the macro level was relevant to the student's answers, according to their verbalizations. Finally, qualitative analyses of these illustrations are also presented and discussed.