Getting Started 
Misconception/Error The student models threedimensional objects with twodimensional shapes. 
Examples of Student Work at this Level The student names the shapes of the lateral faces and bases of the threedimensional objects.

Questions Eliciting Thinking Is your model twodimensional or threedimensional?
Can you model these objects with threedimensional solids?
Which geometric solids does each object resemble? 
Instructional Implications Clarify for the student the distinction between two and three dimensional figures. Remind the student that a geometric solid is a threedimensional figure studied in geometry.
Help the student visualize solids by using an interactive website such as NCTM’s Geometric Solids tool (http://illuminations.nctm.org/). This tool allows the student to virtually explore and manipulate various geometric solids. The student can explore the number of vertices, edges and faces. The student can also make the solid transparent in order to explore other properties. Finally, the student can create a net which can be printed and folded to form a threedimensional solid.
Review the names, types, and properties of prisms, pyramids, cylinders, cones, and spheres. Guide the student to use these solids to model the objects on the worksheet. Explain that models can consist of only part of a solid or the composition of several solids. 
Moving Forward 
Misconception/Error The student describes incorrect models for several of the objects and fails to see the composite nature of the final object. 
Examples of Student Work at this Level The student makes one or more of the following errors:
 Describes the first tent as a pyramid or a rectangular prism.
 Describes the dome tent as a cylinder.
 Describes the circus tent with a twodimensional shape, a cylinder, or a diagonal prism.

Questions Eliciting Thinking How is a pyramid different from a triangular prism?
Think about the shapes of the faces of a dome tent. How would you shape a dome tent if you were using play dough?
Will a cylinder look like the circus tent?
Look at the vertex on the top of the circus tent. What solid will have a vertex like that?
Would you need one or two geometric solids to form a model of the circus tent? 
Instructional Implications Specifically review the differences between a pyramid and a triangular prism. Ask the student to describe the number of and types of faces that make up the surface of each solid. Explain that models can consist of only part of a solid or the composition of several solids.
Consider implementing the MFAS task Estimating Volume (GMG.1.1). 
Almost There 
Misconception/Error The student identifies correct models for the objects represented, but fails to use specific and precise language in the descriptions. 
Examples of Student Work at this Level The student describes the third image as a cone and the fourth image as a cylinder and a cone.

Questions Eliciting Thinking Look closely at the pictures. Are the bases of the third and fourth pictures circles?
Could you be more specific in describing the solids you chose as models? 
Instructional Implications Review with the student the definitions and terminology needed to describe geometric solids including prism, cylinder, pyramid, cone, sphere, and hemisphere. Also remind the student to use precise descriptions of the bases of the solid when needed. Review the terminology used to describe features of threedimensional solids (e.g., vertices, faces, base, and lateral surfaces) as well as names of polygons and terms used to describe triangles (e.g., isosceles, equilateral, and regular).
Allow the student to modify his or her responses to add more specificity.
Consider implementing the MFAS tasks Estimating Volume (GMG.1.1), Estimating Area (GMG.1.1), and Camping Calculations (GMG.1.1). 
Got It 
Misconception/Error The student provides complete and correct responses to all components of the task. 
Examples of Student Work at this Level The student models each object with a geometric solid or a composition of geometric solids. The student uses appropriate terminology to describe the models. For example, the student provides the following descriptions:
 Triangular prism with an isosceles or equilateral triangle as its base.
 Square pyramid or a square pyramid with the top portion removed by taking a horizontal slice a little below the vertex.
 Octagonal pyramid.
 A composite shape formed by placing a regular dodecagonal pyramid on top of a regular dodecagonal prism with congruent bases.

Questions Eliciting Thinking What other examples of real world objects can be modeled by geometric solids or compositions of geometric solids?
Can you think of a real world object that could be modeled by a tetrahedron? An octahedron? 
Instructional Implications Challenge the student to provide more detailed models that include the dimensions of the solids used in the models. Then have the student use the models to estimate surface area or volume.
Consider implementing the MFAS tasks Estimating Volume (GMG.1.1), Estimating Area (GMG.1.1), and Camping Calculations (GMG.1.1). 