This paper explores the effects of infusing writing-to-learn strategies into an inquiry-oriented science unit on simple machines, inventions and inventors. This study used an intact group pretest and posttest design to capture the ecological validity of a classroom of grade 4 students and teacher. The design incorporated quantitative research methods of structured interviews of target students. Students' science understanding and writing skills were documented further with daily teacher reflections and students writing samples. This hybrid research design was selected to provide richness and depth to any conceptual changes detected and to identify potential relationships between writing tasks and science achievement within the limitations of a nonrandom intact group. Student performance on the pretest indicated minimum prior knowledge of simple machines, inventions, and inventors. Students correctly answered 37.3% of the recall items, 9.5% of the understanding items, and 25.3% of all items. Performance on the posttest demonstrated a marked improvement: students correctly answered 75.6% of recall items, 60% of understanding items, and 69.2% of all items. A correlated t-test showed that there was a significant difference between pretest and posttest means. (CCM)