🧪 Rapid Heart–Lung Model Build

Teams use plastic bottles, balloons, straws, tape, and cardboard to build a quick working model that shows lung inflation and a simple heart pump motion. Before building, they review their team "How Might We" statement and user quotes to decide what their model must demonstrate during biking (faster pulse, more oxygen). Students label key parts (heart, lungs, oxygen, blood vessels) directly on the prototype.