Although these three types of environments are very different, they all share some basic characteristics that are believed to encourage learning:

• engaging participants in multiple ways, including physically, emotionally, and cognitively;

• encouraging participants to have direct or media-facilitated interactions with phenomena of the natural world and the designed physical world in ways that are largely determined by the learner;

• providing multifaceted and dynamic portrayals of science;

• building on the learner’s prior knowledge and interest; and

• allowing participants considerable choice and control over whether and how they engage and learn.

These characteristics have emerged from a philosophical stance toward what it means to provide an informal experience, and they also are informed by a growing research base on learning and how best to promote it. This research base, which forms the foundation for this book, represents multiple fields of inquiry that reflect a wide range of interests, questions, and methods. The diversity of approaches to investigating learning outside schools—both how it occurs and how best to support it—makes the evidence base difficult to pull together. At the same time, the research reveals that the opportunities for promoting learning, as well as inherent challenges in doing so, are similar across the three types of informal environments.

Two examples provide insight into different kinds of informal learning experiences. One is a computer game that can be played at home, and the other is a program for adults. They occur in different settings, with different age groups, different structures, and different time scales. The similarities and differences in the two descriptions highlight the shared characteristics of informal environments for science learning, as well as the unique potential for learning that variation in design can provide.