NSES Content Standard E  Science and Technology: Abilities of technological design Grades 5-8, page 165 Design a solution or product. Students should make and compare different proposals in the light of the criteria they have selected. They must consider constraints--such as cost, time, trade-offs, and materials needed--and communicate ideas with drawings and simple models.

 
Benchmark 3B The Nature of Technology: Design and Systems
Grades 6-8, page 51
Design usually requires taking constraints into account. Some constraints, such as gravity or the properties of the materials to be used, are unavoidable. Other constraints, including economic, political, social, ethical, and aesthetic ones, limit choices.

Benchmark 3C The Nature of Technology: Issues in Technology
Grades 3-5, page 54
Scientific laws, engineering principles, properties of materials, and construction techniques must be taken into account in designing engineering solutions to problems. Other factors, such as cost, safety, appearance, environmental impact, and at will happen if the solution fails also must be considered.

Benchmark 12C Habits of Mind: Manipulation and Observation
Grades 6-8, page 294
Inspect, disassemble, and reassemble simple mechanical devices and describe what the various parts are for; estimate what the effect that making a change in one part of a system is likely to have on the system as a whole.

Benchmark 12D Habits of Mind: Communication Skills
Grades 3-5, page 296
Make sketches to aid in explaining procedures or ideas.

Benchmark 12D Habits of Mind: Communication Skills
Grades 9-12, page 297
Make and interpret scale drawings.