expert on orchids, the gardener may be asked to talk to senior citizens at an intergenerational center about his hobby, or become a volunteer docent or gardener at a local botanic garden or park. At this point, the gardener has assumed a new identity—as an expert in the field and as a teacher. Changing individual perspectives about science over the life span is a far-reaching goal of informal learning experiences.

Sustaining existing science-related identities may be more common than creating new ones. For example, in one study, visitors to the California Science Center already expressed a strong sense of connection to science, and their visit reinforced their self-image as someone with interest in or connections to science.

The strands are statements about what learners do when they learn science, reflecting the practical as well as the more abstract, conceptual, and reflective aspects of science learning. The strands also represent important outcomes of science learning. That is, they encompass the knowledge, skills, attitudes, and habits of mind demonstrated by learners who are fully proficient in science. The strands serve as an important resource for guiding the design of informal learning experiences and especially for articulating desired outcomes for learners. Throughout this book, we return to the strands as a way to highlight the learning described in the numerous case studies.