Developers of educational applications that include science content can search the GBLxAPI vocabulary types for science URIs and also the Next Generation Science standards (NGSS) provided in this catalog. The catalog provides the permanent URI that relates to each NGSS standard that would be used for the contextual references in your xAPI statements.
From Next Generation Science Standards
The Next Generation Science Standards (NGSS) are K–12 science content standards. Standards set the expectations for what students should know and be able to do. The NGSS were developed by states to improve science education for all students.
A goal for developing the NGSS was to create a set of research-based, up-to-date K–12 science standards. These standards give local educators the flexibility to design classroom learning experiences that stimulate students’ interests in science and prepares them for college, careers, and citizenship.