The guiding question in this activity is,“Do all liquids have the same density?” Students use plastic specimen collection tubes that are purchased in bulk to determine the density of liquids used. A detailed science behind the activity is provided. Before beginning this activity, we recommend you read Chapters 9 and 12 which are in this book selection. Chapter 9 is an overview of the section and introduces the format used to present ideas for Family Science Night activities. Chapter 12 features activities that we believe to be advanced level. A materials list, references, safety notes, standards, and teacher background information are provided. This book selection also includes the Table of Contents, Preface, Acknowledgments, About the Authors, Introduction, and Index. .