Early experiences develop students' interest and knowledge, and contribute to later success in science- related careers, but many students are behind in STEM areas by third grade. The Next Generation Science Standards (NGSS) offer a vision for science learning that connects core scientific ideas, crosscutting scientific principles and scientific and engineering practices. Scientists and educators at Baylor College of Medicine will develop, evaluate and disseminate new science and health teaching resources for grades K-3 to improve students' learning experiences, skills development and attitudes toward STEM that address NGSS disciplinary core ideas in the life sciences. The resources will be appropriate for use during class time or after school, and will reinforce development of reading/language arts skills. The project builds on multiple successful NIH-funded curriculum development programs and will be evaluated in schools with high enrollments of underrepresented minority and economically disadvantaged students. Project specific aims are to: 1) Recruit and support a team of teacher leaders, who will work together and with scientists and educators to guide the development of four NGSS-aligned curriculum modules (one for each grade: K, 1, 2, 3), designed to provide 3-6 weeks of inquiry-based instruction in school or informal learning settings, with connections to health and reading/language arts. 2) Successively field-test each curriculum module and supporting materials, in collaboration with project partners, using a well-matched comparison group study design, with random assignment of groups to treatment (implementation) or comparison conditions; 3) Revise the modules and supporting materials based on field test outcomes; and develop web-based tools- such as social media-discussions, streaming video lesson demonstrations and downloadable teaching materials-to create a dynamic, web-based curricular and professional development resource for teachers. 4) Disseminate the curriculum and related resources-lesson demonstrations, teacher professional development, and student materials-via the established, high traffic website, BioEd Online (www.bioedonline.org), and through other, more traditional pathways to reach national audiences with high quality, low-cost science teaching resources. All aspects of the project will be evaluated, both formatively and summatively, to gauge the quality and effectiveness with which project components are delivered and implemented, and the overall value of the experiences provided to teachers and students. We will measure changes in teachers' content knowledge, teaching practices, and science teaching efficacy beliefs. In addition, we will examine students' content knowledge and students' motivation and attitudes toward STEM.