Our 8th grade students have been busy working on a STEM design project in science class. In groups, they built their own small-scale model roller coasters using pipe insulation and marbles, and then analyzed them using physics principles. Our students examined conversions between kinetic and potential energy and frictional effects to design roller coasters that were completely driven by gravity. Teams were then judged on the tallest, fastest, most turns and inversions, and most unique coaster.