Facilitating as the Guide-On-the-Side is essential for STEAM student learning. Support student-centered collaboration with strategic and analytic prompting or questioning. After students investigate a science concept, how do they defend their explanation or argue the “correctness” of their theory? Using Claim-Evidence-Reasoning (C-E-R) concepts and graphic organizers to support students’ explanations and ideas about what they are learning in science and engineering is a clear technique to provide student success in meeting this practice. C-E-R can also be used as a summative assessment.