This study focuses on the impact of scientific writing resulting from an inquiry-based instructional approach on students' critical thinking. Students are encouraged in being actively involved in the process of science, by using the Science Writing Heuristic (SWH; Hand and Keys, 1999). The SWH consists of a framework to guide students' science activities as well as a support to prompt students' reasoning about data while writing. Further, the SWH provides teachers with a template of suggested strategies to enhance learning from laboratory activities. As a whole, the SWH seeks to provide authentic meaning- making opportunities for learners. (Author)