Data set that reports on the Findings from a hands-on science intervention to build school students’ agency and epistemic insight into the power and limitations of science. We report on an empirical study that sought to address three questions: A study to extend the cognitive science of insight into the field of children’s developing understanding of the power and limitations of science A study to examine the effectiveness of the Epistemic Insight (EI) strategy which is designed to give each child hands-on, minds-on science A study to examine the effectiveness of the EI strategy to sustain science activity in schools during the challenging conditions of the pandemic 1919 children and 63 teachers from 24 schools in England took part in the project. This includes both primary and secondary schools. The data reported here are taken from ten primary schools representing 1045 children aged 8-12 in years 4 to 7.