This five-year project is designed to provide urban youth in grades 4-8 with innovative, hands-on science experiences in an after-school environment that will enhance their science competencies, while increasing the capacity of after-school leaders. In Years 1-3, nine science modules will be developed, field-tested and evaluated in collaboration with 12 after-school programs in Boston, Massachusetts, serving diverse populations of low-income youth. Each module includes a full color activity book, comprehensive facilitation guide and guidelines that enable students to share results of their investigations on the project website. Topics to be addressed include electricity, planets, invention and habitats. A comprehensive training program will include training for coaches who will provide assistance with the implementation of science modules and offer ongoing professional development for after-school providers. In Years 4-5, the project will be disseminated to after-school programs in Los Angeles, CA, Columbus, OH, and Philadelphia, PA. Additionally, the PI will partner with the National Institute on Out of School Time (NIOST) to disseminate the project nationally using the Cross-Cities Network. All materials will be printed in both English and Spanish, while the website will offer the option of downloading materials in a variety of other languages. It is anticipated this project will serve more than 3,000 youth and 400 after-school providers.