This set of 20 printable STEM challenge cards gives students an engineering problem to solve, a constraint to work within, and a reflection question. Each card is designed for small groups and requires only common classroom or makerspace materials. The challenges in this set have been used with students across a range of grade levels, from early elementary through middle school, and include material lists, time estimates, and teacher tips. A free sample card (the Spaghetti Skyscraper challenge)