Teachers want their students engaged in purposeful learning as soon as they enter the classroom. This volume contains what are commonly called "do-now", "warm-up", or introductory activities meant to focus students during the first few minutes of class while teachers take attendance or do other classroom "housekeeping" chores.The divergent ability levels of many classes make finding appropriate class starter activities challenging. These "Do Nows" are thought provoking and somewhat challenging, but not so difficult that students are filled with questions about how to complete the activity. All of "Do Nows" follow have the same format. Each is a one-page science article. Within each article, blanks have replaced ten words, which can be inferred through the context of the article. Students make their best "educated guess" as to the missing words. The uniformity of the assignment enables all students to experience success as they become accustomed to the format. The back of each warm-up is a blank lined page which can be used as an "exit-ticket" to summarize the day's learning. A series of exit-ticket starter statements are also provided within this volume. Besides use as starter activities, the 180 articles could be used during general classroom instruction and discussion. They are organized by topic: biochemistry, cellular energy, classification, ecology, evolution, genetics, human body systems, reproduction, scientific inquiry, and study of life. Many of the articles would also be appropriate for health classrooms. This is a versatile instructional tool