To best help students meet their learning goals, subgoals often have to be identified and articulated. Coming to understand a particular model requires well-organized knowledge of concepts and inquiry procedures, which often requires time and many “little steps” to reach the larger goal. With a solid understanding of science, the underlying structure of the discipline can help serve as the roadmap to guide a teacher in selecting and sequencing activities, assessments, and with their other interactions with students (NRC, 1999a).

Inquiry and the National Science Education Standards (NRC, 2000) elaborates on some of the more particular elements of inquiry as ability and understanding for the K-4, 5-8, 9-12 grade spans. Mastering the abilities and understandings associated with inquiry in particular is difficult and can seem elusive even for the most experienced teacher. Such detail would be useful for a teacher when articulating subgoals to support student inquiry in the classroom. Box 5-1 is an example of delineation of the fundamental abilities and understandings for inquiry at the 9-12 level. For further elaboration, the Standards (NRC, 1996) offer complete descriptions of scientific inquiry as abilities and understandings at the K-4, 5-8, and 9-12 levels.

This process of organizing content into meaningful steps and activities is one of the most demanding aspects of teaching. The teacher needs both a clear idea about the structure of the concepts and skills involved and knowledge of the ways in which students may progress. If intermediary goals are too ambitious, the step towards growth may be too difficult, while if they are too slight, students may not be challenged. An appropriate subgoal is one that goes beyond what the student can learn without help but is within reach given a reasonable degree of teacher support. For more background on the theoretical roots presented here, see Vygotsky's discussion (1962) of the zone of proximal development. Teacher knowledge of common misconceptions and of tools available to promote conceptual reconstruction or to promote fluency with new skills can powerfully inform the process of structuring the curriculum.

Teachers also need ways to respond to the information they elicit from