"Adler shows his customary skill for explicating mathematical concepts in this smart exploration of floatation and density. Several experiments allow for a hands-on approach: Adler suggests filling a sink with water and testing whether different objects float, as well as using modeling clay to demonstrate how shape is as important a factor as density. Raff’s pastel palette and cheerful characters keep the mood light and pair well with Adler’s explanations, which are clear without being dauntingly technical." —Publishers Weekly (starred review)