Energy is difficult to define. The purpose of this assessment probe is to elicit students’ ideas about energy and is designed to reveal how students define or describe energy. This probe is best used with students in grades 4–12. When used with grades 4-5, remember that students are not expected to define energy at this grade level. The probe is provided in English and Spanish. A materials list, teacher notes, standards, assessment, and references are provided. This book selection also includes the Table of Contents, Preface, Acknowledgments, Dedication, About the Authors, Introduction, and Index.