Cao Chong weighs an elephant

This tale of a boy who uses the principle of buoyancy to weigh an elephant is based on real Chinese prodigy Cao Chong (born 196 AD) and inspired by the Chinese author's grandfather's stories. With a blandly descriptive text and serviceable watercolor illustrations, the story just isn't engaging enough to inspire scientific exploration. Extensive curriculum worksheets are included, but explanations lack clarity. Bib. (c) Copyright 2018. The Horn Book, Inc., a wholly owned subsidiary of Media Source, Inc. No redistribution permitted.

When a giant elephant arrives as a birthday present for the prime minister of Han, his 6-year-old prodigy son, Cao Chong, orchestrates a plan to measure the beast's weight.Amazed by its size, spectators begin to place wagers on the elephant's enormous weight. But without a scale large enough and strong enough to withstand the animal's hefty mass, a challenge is presented to the prime minister's advisers. Much deliberation ensues, and when a suggestion to slice the elephant into smaller pieces to fit on a regular scale is made, Chong intervenes with a more clever and ingenious plan. The mathematical puzzle is deftly explained in a story based on ancient Chinese history. Chong places the elephant in a boat, marks a water line on the outside of the boat, replaces the elephant with as many rocks as needed to lower the boat to the same water level and combines the principal of buoyancy with the total volume of rocks to calculate the elephant's weight. Black-outlined colorful paintings provide a lush backdrop for the story's circa-200 C.E. China setting, with royal characters in long robes and bejeweled crowns. An addendum includes well-defined activities for understanding buoyancy and scale measurement, a succinct history and geography of the Han Dynasty, and a biography of Cao Chong. Nicely produced and balanced in its instructive approach. (Picture book. 5-8) Copyright Kirkus Reviews, used with permission.