Book excerpt: Challenge your students to learn more about the scientific world around them. This packet contains activities designed to be completed in 15 minutes or less and can be used as lead-in exercises for classroom discussion, homework, or extra credit assignments. The activities help strengthen students’ understanding of key scientific concepts and examine thought-provoking issues. New worlds are explored as students answer questions, complete Extra Challenges, and solve problems. This is is a valuable tool that should be used in any science classroom!