Things That Float and Things That Don't - Hardcover

*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