BrainPOP Science is a research-based program that has been shown to be effective in improving and quickly developing students' scientific reasoning skills. This white paper presents a comprehensive case study conducted in school districts in the Southeastern United States. BrainPOP Science is one of the leading supplemental middle school programs. This study investigated the effectiveness of BrainPOP Science for enhancing students' proficiency in constructing scientific explanations and arguments by utilizing evidence and reasoning according to the Claim-Evidence-Reasoning (CER) framework. Data were collected from students' first and fourth CER submissions to explore changes in CER skills over time. A multivariate analysis of covariance (MANCOVA) was conducted to assess the joint significance of the difference between students' first and fourth claim, evidence, and reasoning subscores and total CER scores, as well as to examine the role of BrainPOP Science usage as a covariate. The results reveal significant learning gains on average between students' first and fourth CER scores. Multivariate analysis found the model was jointly significant for the total CER score, as well as each claim, evidence and reasoning subscores. A significant effect of BrainPOP usage was also observed, such that any usage (low, moderate, high) increased the total CER score, and evidence subscores. Additionally, moderate usage increased claim subscores, and moderate and high usage increased reasoning subscores. A key implication of this research is the expansion of teacher capacity. BrainPOP Science provides educators with ready-to-use, standards-aligned investigations that effectively support multidimensional science learning. The platform offers a scaffolded approach to evidence-based writing, incorporating exemplar answers and assessment rationales. This strategic integration of teaching resources empowers educators to confidently guide students in their development of Claim-Evidence-Reasoning skills, which is transferable to high-school readiness and preparation for state summative assessments.