THE MISSING CUCKOO CLOCK

Summer-camp kids get (scientifically) physical.

Falling between a boxed definition of gravity and explanations of how that force interacts with others, the story is largely a framework for nonstop real-life demonstrations of gravity in action. Readers see it at work on clock weights, dripping water, a beach ball, random falling objects—and horse-mad new camper Megan, who falls a hair below the height requirement to ride in the afternoon, but (after a night spent lying down) measures a half-inch taller the next morning. Helmer supplies brightly colored cartoon panels featuring a multicultural crew of young campers engaged in general horseplay or watching in wide-eyed wonder as a counselor explains how a mechanical clock works or concocts simple physics demonstrations. Even the titular cuckoo clock swings past as just a MacGuffin for showing how a pendulum works.

Predominantly instructional, but light enough not to sink beneath the weight of its purpose.