The purpose of this study was twofold: to determine if, and how integrating the writing process with the second grade science curriculum in the classroom improved science learning and impacted higher order thinking skills. Instruction incorporated Writing-to-learn concepts with lecture, laboratory experiments, and writing opportunities in science. A teacher-made unit assessment was used as a Pre-Test and Post-Test. Percentage scores were compared to determine the level of content mastery in science. Student work was collected in portfolios and assessed using a rubric to determine evidence of higher-level thinking. Data were triangulated using the student portfolios, student self-assessments and researcher notes. The population was a second grade classroom, at an elementary school in a school district in Houston, Texas. A mixed-methodology design was used over a four-week period. This research study showed that writing in the science classroom improved students' learning and impacted higher order thinking skills and student achievement gains.