The purpose of this assessment probe is to elicit students’ ideas about Earth’s history. The probe is designed to reveal how old students think Earth is. It is important that students include in their explanation the type of evidence they think scientists use to support their ideas about the age of Earth. Students should give an estimated age, instead of a range, in their explanation. 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.