Comics have an important role in non-formal learning environments. However, how comics may be effective teaching/learning activitities in formal education is an ongoing debate in literature. The purpose of this study is to create and evaluate a series of instructional comics about heat related concepts to be used as teaching/learning activities in real classroom settings. This research is designed as a case study aiming to observe and explain students' reactions to the implementation of an instructional intervention. In this study, six instructional comics about heat related concepts having empty speech balloons were constructed and implemented to a group of 6th graders as balloon completing activities. It was observed that many students completed empty balloons with several wrong statements, and it was concluded that students' wrong statements have crucial feedback for dealing with students' preconceptions about science concepts.