This document discusses challenges with implementing constructivist approaches to teaching science in classrooms. It argues that the phases of constructivist teaching sequences are often described separately but need to be integrated in practice. It is also difficult for teachers to plan activities that address each individual student's existing understanding given class sizes. The document introduces concept cartoons as an innovative way to engage students in thinking about science concepts by presenting alternative views in a visually appealing format. This allows teachers to elicit students' initial ideas and challenge them to develop their understanding in a practical classroom-based approach.