Engineering involves using tools and materials to build structures. Some basic tools include screwdrivers, hammers, and drills. Common materials are wood, lumber, and bark. Important things to build are shelter, benches, and tables, which provide places to live, sit, and use items. Wood sizes can vary and are described by measurements like 3 by 6 or 7 by 9. The right materials must be selected for each project. For example, wood is better than stone for a dining room table. Proper engineering allows people to construct buildings and other items.