Project Summary The purpose of this SEPA project is to design and field-test The Science of Essential Balance (SEB) curriculum for high schools. Building on an established university-public school SEPA Partnership including 5 school districts in the Piedmont region of North Carolina, this project seeks to develop a 40 lesson curriculum to teach the science about energy-balanced living in Healthful Living Course of Study. The curriculum will incorporate mobile technology to deliver course assignments that lead students through the 5-E science learning cycle to engage, experiment, explain, elaborate, and evaluate data they collect from themselves about nutrients (especially calories) intake and expenditure. Learning the science about energy balance in the physically active healthful living lessons will provide opportunities for students to study the relationship between nutrition, exercise, injury prevention, and obesity prevention using scientific inquiry processes. The knowledge learned from this SEB curriculum may form a foundation for students to further study and understand preventive medicine. Efficacy of the curriculum will be determined in an Evaluation Study (Phase 1) and a Dissemination Study (Phase 2). In the Evaluation Study, 20 high schools from the established SEPA Partnership districts will be randomly assigned to either the SEB condition or a control condition in the first three project years. A quasi-experiment design will be used in the Dissemination Study to determine the sustainability and transferability of the SEB curriculum using a sample across the U.S. The curriculum efficacy evaluation will be based on evidence representing student achievement outcome, teacher assessment of the curriculum, and community satisfaction about students? understanding demonstrated in student-led community events. A three-level Hierarchical Linear Model will be used in both studies to ensure validity, reliability, and generalizability of evidence for curriculum efficacy.