Teachers often struggle to implement inquiry-based science teaching. To support them, IndagApp—a 3D educational app that offers curriculum-aligned, inquiry-based lesson plans—was designed. The app is rooted in the inquiry phases recommended in best-practices literature, which arguably align with most international standards. This study describes IndagApp and evaluates its usability with fifth-graders from two elementary schools in Spain (N = 43). The system usability scale (SUS) and the Pictorial-SUS were used to collect students' feedback on usability. Both frequentist and Bayesian analyses were conducted to compare the mean SUS score with established benchmarks for usability. The results showed that IndagApp had high usability ratings, with most students rating it as the “Best imaginable” or “Good.” The mean SUS score was 84.816, which was significantly higher than the benchmark score of 68. There were no differences in usability between girls and boys, and students in private and public schools. These findings suggest that IndagApp is a valuable resource for inquiry learning in elementary grades and has significant implications for science education and science teacher professional development, as it helps teachers adopt reform-oriented teaching practices that align with the curricular standards and goals.
