Book Review
What is the World Made Of? All About Solids, Liquids, and Gases by Kathleen Weidner Zoehfeld, is a good introduction to the concept of matter for preschoolers through early elementary grades.  

The author explains that matter is everywhere, and that it is found in solid, liquid or gaseous states. Several experiments or activities are suggested to help define the different states. Water is discussed in detail as a special substance that moves relatively easily between all three states. The pictures are colorful and engaging and illustrate the concepts well. The book should answer some basic questions and inspire further curiosity. Parents and teachers who read this book to children should easily be able to augment the experience with more "what if?" questions.  

A good introduction to the science behind everyday experiences, well presented for a very young audience.  I would give it a full 5 stars and recommend it as a full Cornerstone.

~ K.K., MLS, Brunswick