In 2000, the National Science Foundation created the National Science Digital Library (NSDL) to provide organized access to high quality resources and tools that support innovations in teaching and learning at all levels of science, technology, engineering, and mathematics (STEM) education. In addition to providing an organized point of access to high-quality STEM content, NSDL also provides open-access, non-proprietary tools to stimulate new ways to access and use science education information in an easily accessible online environment. NSDL currently catalogs over 60,000 resources from 57 digital collection providers and thousands of web sites. Individual resources in the library are characterized using qualified Dublin core metadata. 

NSDL makes an ideal testbed for researchers interested in exploring innovative approaches into “digging into data” over rich collections of web-based educational resources. NSDL uses a Fedora-based open-source digital library platform of technology and standards (NCore), creating a dynamic information layer on top of library resources. Collections, resources, and this information layer are easily accessible to researchers via a number of application programming interfaces. The repository contents can be accessed directly using the Digital Repository API. Additionally, a Search API is available for searching directly over NSDL collections. Finally, there is also the Strand Map Service API for searching and visualizing NSDL collections according to K-12 learning goals. This web service protocol supports the construction of interactive knowledge map interfaces based on the learning goals articulated in the American Association for the Advancement of Science (AAAS) Benchmarks for Science Literacy and the learning progressions and strand maps published in the AAAS Atlas of Science Literacy. The library’s Dublin core metadata descriptions can also be harvested using OAI-PMH. 

Documentation:

Digital Repository API documentation is available here:http://wiki.nsdl.org/index.php/Community:NDR

Search API documentation is available here:http://wiki.nsdl.org/index.php/Community:Search 

Strand Map Service API documentation is available here:http://wiki.nsdl.org/index.php/Community:StrandMaps