In this lesson, students learn that scientists and engineers make observations over time. They read about Ada Twist in the book Ada Twist, Scientist, by Andrea Beaty. After reading, students will recognize that scientists and engineers make observations over time as they design an experiment to see what would happen to marshmallow confections such as the commercial brand Peeps in different liquids. This book selection highlights the practice of asking questions and defining problems, and it includes the Table of Contents, Foreword, Acknowledgments, About the Authors, and Index.