Learn how simple machines make work easier in these colorful nonfiction picture books all about science and engineering! If you were building a tree house, what could you use to keep the boards together? You could use nails, but you might also use screws. Screws are one of the simple machines that are designed to make different kinds of work easier! Lifting, pulling, pushing, and fastening things together--all these tasks are more efficient when you use a simple machine. In Screws Keep Things Secure: Simple Machines for Kids, readers ages 5 to 8 learn how a screw's shape can pull things together or push things apart or even move heavy objects from one place to another! Scientific concepts including forces and mechanical advantage come clear with engaging illustrations and lots of real-life examples that kids can spot in their home, schools, and neighborhoods. An introductory poem offers language arts connections while a hands-on activity at the end reinforces concepts in the book. A glossary and photographs offer even more supplemental learning opportunities. Screws Keep Things Secure is part of a six-book set of Picture Book Science books designed to introduce young engineers to physical science concepts. Other titles are Wedges Make a Point, Inclined Planes Ramp It Up, Pulleys Pull Their Weight, Wheels Make the World Go Round, and Levers Lessen the Load. All books are leveled for Guided Reading level and Lexile and align with Common Core state standards and Next Generation Science Standards. All titles are available in paperback, hardcover, and ebook formats.