Chemistry

Gr 4–6—It's nice to have a little built-in flexibility for a club or classroom activity. The four projects in each of these books are presented in levels—if you've completed one level and still have time, you can try the next, or if a step took longer than expected, you can pause your project without having to backtrack to square one. Clean design with neatly laid out instructions helps ensure success, and readily available materials reduce planning time. Chemistry stands out, with reaction projects that work despite errors; yeast will eat sugar regardless of how your balloon is aligned. By contrast, many of the built objects in Motion and Electronics will fail if construction is fumbled. Engineering is particularly suited to the incremental nature of these books. Triangles can become a truss bridge and then a geodesic dome as materials are multiplied and combined.