Book excerpt: Kids will learn how things they encounter every day operate by building their own models with this hands-on activity book. Projects include building a working model of the human hand's muscles, bones, and tendons using drinking straws, tape, and string; using a pair of two-liter bottles and a length of rubber tubing to learn how a toilet flushes; and discovering how musical instruments make sounds by fashioning a harmonica, saxophone, drum, flute, or oboe. All devices are designed to use recycled or nearly free materials and common tools. Kids are encouraged to modify and improve the designs, or create an entirely new device using the concepts explored. Each project includes materials and tools lists, step-by-step instructions with photographs, a summary of the science concept demonstrated, and follow-up questions to gauge student understanding for use in the classroom.