Title Flywheel Spinner 🔁 Rotational Inertia & Stored Energy (Grades 4–9) — 2-Page STEM Challenge + Data Table & 20-pt Rubric Short blurb Students design a string-pull flywheel and test how mass placement and hub size affect spin time. Quick build, clear metrics, and a student-friendly 20-pt rubric—print & go. Full description In this hands-on challenge, learners build a cardboard (or lid) flywheel with a string-pull axle, then investigate how rotational inertia changes with mass pl