Photosynthesis is a complex process that involves the implementation of several reactions which, many times, makes this content difficult for students to understand. The objective of this study was to investigate if an interactive didactic model, crafted with simple materials, could facilitate the understanding and learning of students on photosynthesis. Initially students of first year high school class from a public school Western of Paraná were asked to diagram what they knew about photosynthesis and respond to a questionnaire. It was concluded that many of the students’ prior concepts were general or inaccurate, such as the idea of photosynthesis being the process of respiration in plants, and O₂ coming from the CO₂, not from the photo-oxidation of water. These prior conceptions were important for planning the approach to the subject. The process of photosynthesis was then covered in lecture and dialogued, using the interactive didactic model to highlight the explanations. A new questionnaire was completed by the students, and concluded that the use of the interactive didactic model was efficient, since it helped to consolidate correct concepts and simultaneously, introduced new ones as well it shook the equivocal relations.