This chapter addresses experimental and field observations, which include aspects of Asking Questions and Defining Problems; Planning and Carrying Out Investigations; Constructing Explanations and Designing Solutions; and Engaging in Argument From Evidence. Simply getting out into the field to see some of the features and processes talked about in class engages students in the field and gives them an understanding of how our conclusions in geology are tied to field observational data. In this chapter, the example activity design (EAD) involves mapping of horizontal rock layers, a first step in understanding how we know about the changes on Earth through time. It can also serve as an introduction to geological mapping. One challenge of this EAD is to find the right location for the project. A materials list, teacher background information, safety practices, and outcomes are provided. This book selection includes the Table of Contents, Acknowledgments, About the Authors, About the Book, Introduction, and Index.