The purpose of this lab is to introduce students to the core idea of forces and motion by having them explore ”What Is the Relationship Between the Mass of an Object and Its Acceleration During Free Fall?” The Teacher Notes provide the connections to standards, references, a timeline, safety notes, information on materials and preparation, and instructions for facilitating the lesson and assessing student outcomes. After the Teacher Notes, you will find a Lab Handout and Checkout Questions. Before beginning the lesson, we recommend reading Chapters 1 and 2, which are included in this book selection. Chapter 1 provides an overview of Argument-Driven Inquiry (ADI) with an explanation of what happens during each of the eight stages of ADI, which are the same for every ADI investigation. Chapter 2 focuses on the lab investigations that were designed using the ADI instructional model. These investigations are not designed to replace an existing curriculum, but to transform the laboratory component of a science course. This book selection also includes Table of Contents, Preface, Acknowledgments, About the Authors, Introduction, Appendixes, Image credits, and Index.