Crystal Models Made from Clear Plastic Boxes and Their Use in Determining Avogadro's Number

Easy-to-make crystal lattice models constructed from clear plastic boxes or pieces of acrylic plastic are described. The models include body-centered cubic, face-centered cubic, and more difficult to make hexagonal unit cells. They also include some mineral structural types such as sodium chloride and graphite. The use of these crystal lattice models in the classroom is presented, with an application in calculating Avogadro's number.