This Instructional Activity is a part of the Lesson 16, Unit 1, Grade 6. This activity clarifies the distinction between volume and surface area and illustrates that two polyhedra can have the same volume but different surface areas. Students build shapes using two sets of eight cubes and determine their volumes and surface areas. Since all of the designs are made of the same number of cubes, they all have the same volume. Students then examine all of the designs and discuss what distinguishes shapes with smaller surface areas from those with greater ones.