Purpose Mobile technologies, such as QR codes, play a particularly important role in scaffolding the child user’s active learning in informal environments. The purpose of this paper is to examine the impact of QR code scanning on two informal learning outcomes: increased interest and greater knowledge understanding. Design/methodology/approach In total, 91 children and their families participated in the study as part of the iQ Zoo Project. Children in both the smartphone group and the control group completed were assessed qualitatively and quantitatively before and then after their zoo visits. Findings Qualitative findings suggest that most children’s interest in learning about animals was sustained as a result of the experience. Quantitative results reveal that QR code scanning was effective in promoting knowledge gains, especially on subjects that are challenging for the informal learner. Findings were comparable across the younger (5–8) and older (9–12) age groups. Originality/value This study provides empirical support for the value and usefulness of mobile technologies such as QR code scanning for children's learning in informal environments.