The purpose of this assessment probe is to elicit students’ ideas about the structure of the solid Earth. The probe is designed to find out if students recognize that Earth’s outer layer (crust) is mostly solid rock with a thin layer of soil on top. It is best used with grades 3–8, and can be extended by encouraging students to draw a picture to visually represent their conceptual model. It can be used as a precursor to elicit ideas related to several of the standards and core ideas that involve weathering and erosion, and also provides an opportunity for students to use the scientific practice of developing and using a model. A materials list, teacher background information, references, assessment, and outcomes are provided. This book selection includes the Table of Contents, Foreword, Preface, Acknowledgments, About the Authors, Introduction, and Index.