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.

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.