A lot of emphasis in science is placed on the how and the why: How is energy created? Why does the body release gases? But just as important is understanding where energy, liquid, gases, and solids go after they have been used! This set presents readers with essential information about the states of matter, emphasizing some of the most high-interest science topics around--bodily functions! Full-color illustrations and diagrams break down complex ideas to make them understandable to readers of many levels.