structuring the data, interpreting and evaluating the data, and using results to develop and refine arguments, models, and theories.

Scientific knowledge builds on itself over time. Proficient science learners understand that scientific knowledge can be revised as new evidence emerges. They can also track and reflect on their own ideas as those ideas change over time. This strand includes ideas usually considered part of understanding the “nature of science,” such as the history of scientific ideas. However, it focuses more on how scientific knowledge is constructed. That is, how evidence and arguments based on that evidence are generated. It also includes students’ ability to reflect on the status of their own knowledge.

Strand 3 brings the nature of science into practice, encouraging students to learn what it feels like to do science as well as to understand what the game of science is all about. Strand 3 focuses on students’ understanding of science as a way of knowing. Scientific knowledge is a particular kind of knowledge with its own sources, justifications, and uncertainties. Students recognize that predictions or explanations can be revised on the basis of seeing new evidence, learning new facts, or developing a new model. In this way, students learn that they can subject their own knowledge to analysis.

When students understand the nature and development of scientific knowledge, they know that science entails searching for core explanations and the connections between them. Students recognize that there may be multiple interpretations of the same phenomenon. They understand that explanations are increasingly valuable as they account for the available evidence more completely. They also recognize the value of explanations in generating new and productive questions for research.