From School Library Journal
K-Gr 2–This introduction to density offers new vocabulary in bold font, delightful soft-hued illustrations, and clearly focused content on flotation. The strong examples provide extension activities that can be done at home or in the classroom. The images enhance the concept as readers meet a boy, a girl, and their dog as they embark on an adventure to discover what will float and what won't. For example, a spread depicting how density is relative to the size of the object shows the dog looking over a kitchen sink full of water as a piece of aluminum foil floats as a loose ball and sinks as a tight one. This title supports the Common Core State Standards that focus on measurement skills, interpretation of data, and incorporation of key ideas and details in the text. Recommended for math collections in public and school libraries and classroom shelves.–Melissa Smith, Royal Oak Public Library, MIα(c) Copyright 2013. Library Journals LLC, a wholly owned subsidiary of Media Source, Inc. No redistribution permitted.
*Starred Review* In this engaging book on density, Adler explains the concept in terms a child can understand; he does so through straightforward text and basic density-related activities. The brief explanation that something’s density is “its weight relative to its size” is useful, but the varied ways of demonstrating the concept are even better. A loosely crumpled ball of aluminum foil floats in water, but a tightly packed ball sinks because of its greater density. A lump of modeling clay sinks, but shaped into a boat that “encloses air,” the same clay floats. Other activities show how the density of water changes when it’s frozen or made salty. The section on “guessing which things float and which things don’t” is particularly fine, not only because it’s challenging and fun but also because it leads kids to use elements of the scientific method without mentioning the term. Created with ink washes and drawings and “assembled digitally,” Raff’s jaunty, imaginative illustrations feature two curious children and their dog playing around with objects and water. It’s rare to find a picture book that uses simple hands-on activities so successfully, leading young children to a fuller understanding of a scientific concept. Preschool-Grade 2. --Carolyn Phelan