Teachers' Domain leverages WGBH's extensive broadcast, video, and interactive programming resources to provide elementary through high school teachers with rich materials designed to support standards-based teaching and learning materials. The website offers contextualized, rich media in several content areas that teachers can access easily, free of charge, and use within their classroom and professional development.

In an effort to support science teachers, the WGBH Educational Foundation expanded its Teachers' Domain digital library initiative to include an integrated set of pathways that promote, guide, and support the effective use of rich-media resources, both in the classroom and for professional development. Three partners joined WGBH in this effort: the Biological Sciences Curriculum Study (BSCS), the Harvard-Smithsonian Center for Astrophysics, and the Digital Library for Earth System Education (DLESE). CCT has been asked to conduct an evaluation of the newly expanded Earth and Space Science Collection.

The overarching goal of the Teachers' Domain Pathways to Science project is to get high-quality rich-media into the hands of K-12 science educators and students in formats directly targeted to their teaching and learning needs. Teachers' Domain already addresses each of the core subject areas in the K-12 science curriculum (Life Sciences, Physical Sciences/Engineering, and Earth/Space Sciences). As part of this project, WGBH worked toward the following new goals:

• Aggregate video, interactive, and other rich-media resources, drawn from across the NSDL and other archival collections
• Conform all assembled materials to the validated Teachers' Domain model, which includes background essays, lesson plans, and correlations to both national and state-level standards
• Create multiple pathways to facilitate effective use of these resources, through online courses and workshops, classroom videos, and CD-ROM demonstrations
• Leverage pre-existing digital collections, online courses, classroom footage, standards-correlation and metadata protocols, and customization tools already produced by WGBH and included at no additional cost to the project
• Conduct dissemination, promotion, and outreach to assure widespread distribution and informed use in schools and informal educational settings, in part through the prospective engagement of the public television system

Using a combination of online surveys, teacher interviews, and patterns of usage, CCT's evaluation explored the following research questions:

• In what ways have WGBH improved the approximately 40 NSDL resources it has reworked"?
• What is the impact of resources contained within Teachers' Domain Pathways on middle school students' knowledge of Earth and Space Science?
• How effective is the Earth and Space Science Professional Development module in supporting student learning and teachers' classroom practice?