and iterative process, collaboration (team work)) Big Idea 2: Concepts (systems, balance, assumptions, uncertainty, open-ended or ill-defined problems, boundaries, dimensional analysis, input/output, spatial reasoning and visualization, equilibrium, stability, state and rate of change) Big Idea 3: Tools (technical and non-technical communication, regression, statistics and probability, risk assessment, resource management, communication/defending, justifying solutions, persuasion, collaboration (team work), project management, computer-aided and mathematical models, pencil & paper tools) Big Idea 4: Engineering and Society (ethics, sustainability, Grand Challenges, different disciplines, interaction