What do a slide, a flagpole, and a tricycle have in common? They illustrate principles of physics relating to simple machines: an inclined plane, a pulley, a wheel and axle, a wedge and a lever. The emphasis in each description is that simple machines make work easier. An inclined plane can be a simple ramp, a winding road leading to the mountain top, or a screw. The wheel and axle of a tricycle is shown next to the more complex Ferris wheel. Children will be drawn to the depictions of the machines in familiar situations such as turning on a water faucet or playing on a seesaw. The charming illustrations, featuring children, adults, and even a cat, enhance the impact of the message by depicting a small community going about their lives and using simple machines to make work easier.

K-Gr 3 While Adler and Raff's Things That Float and Things That Don't (Holiday House, 2013) succeeded in introducing STEM principles, their latest picture book offers more confusion than clarification in its attempts to cover a variety of simple machines in a single title. The soothing, sumi ink-washed illustrations follow two children, a cat, and a lumberjack as they explore wedges, inclined planes, levers, wheels and axles, and pulleys. The screw is mentioned merely as a sidebar of inclined planes. The book lacks visual cues and headings, and readers may be caught unawares jumping from one machine to the next, especially as illustrations build upon one another. Vocabulary words are in bold, but most are never clearly defined, and the concluding sentence leaves readers hanging on a pulley: "With the pulleys, the motor in the crane needs less lifting power." Libraries will be better served by Bellwether's "Simple Machines," which covers one simple machine per title. VERDICT An attractive yet unsuccessful attempt; give this one a miss. Jennifer Wolf, Beaverton City Library, OR