This unit is most exciting. Students will work in their teams to actively engage in the building of a well-designed and testable prototype. Teams will develop an agreed upon, step-by-step explanation of the assembly directions for the building of their prototype and will also have a design solution that satisfies all criteria. They will keep in mind that the materials used for their prototypes may have to be adjusted based on cost, availability and access to the equipment necessary for the fabrication process. Teams will perform several different tests, which may be conducted at different phases of the construction process. Teams will define and justify the testing method and they will need to demonstrate that they are using sound engineering, scientific, and mathematical principles. The collected test data will be evaluated against the criteria that the team established to determine success or failure. Teams will understand that the success or failure of the prototype is not the goal of engineering design and development. EDD is all about the process.