Illustrates the differences between solids, liquids, and gases. Explains what causes an object to change between solid, liquid, and gas, and how the states of matter affect everyday life. Colorful photographs and diagrams help illustrate each science concept. A chart compares the concepts head-to-head to help solidify readers' grasp of the material. Additional features include a table of contents, a phonetic glossary, an index, and sources for further research.