Learning Iteration for Grades 2-3: Puzzles vs. UMC in Code.org

n a project partially supported by research grant PANN20_00690 to Italy's CINI National Lab "Informatica e Scuola", we compared the effectiveness of two alternative instructional methods applied to scaffold the learning of iterations for children at grades 2-3. Eight university groups across the Country collaboratively run the project in two successive rounds throughout the year 2022. Teachers' feedback collected across the two rounds helped fine-Tune the deployment of the interventions. The experiment results show that the two alternative interventions have measurable outcome differences in the short term.