In this lesson, students learn that scientists and engineers are generous. They read about Katherine Sessions in the book The Tree Lady: The True Story of How One Tree-Loving Woman Changed a City Forever, by H. Joseph Hopkins. After reading, students will engage in a scientific experiment and observe how light affects a plant leaf. This book selection highlights the practice of obtaining, evaluating, and communicating information, and it includes the Table of Contents, Foreword, Acknowledgments, About the Authors, and Index.