Holding a Door Open: Wedge vs. Wheels and Axles (First Step Nonfiction: Simple Machines to the Rescue) - Softcover

"In these simple episodes, big, glossy color photos depicting a diverse crew of children and adults demonstrate how various kinds of simple machines can be helpful, or not, in performing common tasks. Noah, for instance, has a big pumpkin to move, and though his mother shows how a shovel's lever action can lift it, a small wagon actually allows him to wheel it away. Similarly, Liz (with a priceless expression on her face) stops her father from trying to move sliced tomatoes into a salad bowl with a sharp knife and instead tips the cutting board to accomplish the task more safely. Though the writing is occasionally unclear and explanations throughout of how the simple machines work are skimpy or, in some cases, missing altogether, newly emergent readers will come away with both a grasp of how simple machines differ from one another, as well as with some exposure to special terms like fulcrum and force. Each volume closes with an open-ended question ('How can you use a wedge?' for instance), and a perfunctory glossary and index. VERDICT: Suitable STEM selections for the youngest scientists."--School Library Journal, Series Made Simple