The purpose of this study was to determine whether or not my practice of implementing Interactive Science Notebooks (ISN) impacts 4th grade students writing in science. Through this action research, students' writing was analyzed to determine whether the use of ISN affected students' use of details, support claims and justifications in their written responses. Also through the use of the Interactive Science Notebook, students' use of science vocabulary in their writing was also analyzed. Finally, students' reflective writing practices were examined in order to determine how students understood and explored physical science. A triangulation of data gathered consisted of the use of rubrics, focus groups and one-on-one conferencing. The data collected from this action research implied that the Interactive Science Notebooks did indeed have an impact on students' scientific writing. Students writing reflections demonstrated an increase in the use of claims and evidence, and meaningful questions related to the science topic investigated.