The goal of this phase is to design a scenario that presents the phenomenon in a way that highlights what is puzzling so it is clear to students there is something to be figured out using their 3D understanding.
Identify what is puzzling to students about the phenomenon. Thinking like a student in the context of the learning experiences leading up to the assessment is helpful to identify the puzzling aspect. (Sometimes a comparison is a useful way to present a phenomenon as puzzling.)
Include data and information that motivate the initial question, engage student interest, and make the phenomenon visible in multiple modalities.
Review the scenario with the Assessment Scenario Checklist.
Review your scenario in student hat to see if it engages student interest and sets up authentic use of the 3Ds.
Make sure that images make the phenomenon visible and aren't just a representation. For example, the extremities of Siamese cats change colors in different temperatures. One photo of a Siamese cat doesn't make the phenomenon visible.
Remember that the scenario should give just enough information to stimulate curiosity. Additional data and information can be introduced later in the task as needed for sensemaking.