Using toothpaste and soap are acts most of us do every day, and this selection in the “Chemtastrophe!” series explains that we have chemistry to thank for most of the products we use to clean ourselves—and our homes. A brief overview of chemistry includes explanations of mass, volume, states of matter, and more. “Fun Facts” sidebars reveal chemistry-related tidbits such as the fact that over 1,800 years ago, an ancient Greek doctor encouraged people to wash using soap but the practice did not become common until the early 1900s. Inset “How We Know” sections offer historical information.