Evaluating designs and offering feedback!

Third graders are using the engineering design process to improve their obstacle course designs.  Sometimes the force of their breath is too great for the design they're created, so they're working to manipulate the available materials to keep the cotton ball on track. Maybe the materials they chose are causing too much friction and the cotton ball can't move forward like it is intended to. They're also getting feedback from their peers, which is an incredibly important part of an engineer's work.