The purpose of this probe is to elicit students’ ideas about charged objects. It is designed to reveal whether students recognize that one can only make a limited conclusion about charge during an interaction where objects are attracted to each other. Two interaction examples using plastic balls are provided. Students are asked if these two examples are convincing evidence that both balls in each example are electrically charged. A materials list, teacher notes, standards, assessment, safety notes, and references are provided. This book selection also includes the Table of Contents, Preface, Acknowledgments, About the Authors, Introduction, and Index.