The past decade, inquiry-based learning in science education supported by technology has been promoted. Because of the all-in-one functionality and the possibility to serve as facilitators for authentic learning experiences, tablet devices are interesting tools to promote such learner-centred approaches. However, research is lacking to inform how the teacher should intervene during technology-enhanced science inquiry. The little available research shows that teachers often use technology to support traditional, teacher-centred practices, since these traditional practices fall short of meeting students' differentiated needs. More research is needed to investigate how teachers should scaffold inquiry learning using tablets in the classroom. In this light, a quasi-experimental study was set up during a four-week natural science course in seven secondary classes (n = 149). This study investigated the impact of the teacher's behaviour during tablet-supported inquiry learning on students' conceptual knowledge and their inquiry skills. An inquiry-based tablet application has been developed for this study. Using a two-by-two factorial design, the teachers were assigned to one of the four conditions: 1) acting as a reactive teacher, 2) acting as a proactive teacher, 3) a combination of both types of teacher roles or 4) acting without a predefined role (control condition). Reactive teachers only act when students ask questions by using their tablets to alert the teacher. Proactive teachers, who can follow the learning progress of their students through the tablets, anticipate on potential issues before they happen. The combi-teachers use both types of scaffolding (using the tablet to follow the questions of the students and to follow the progress of the students). Teachers in the control condition were not provided with a tablet to follow the learning progress and students could not ask questions by means of the tablet. Students in all four conditions used the inquiry-based tablet application. Results showed a significant improvement of conceptual knowledge for all students (Wilks' lambda = .65, F(1, 102) = 54.18, p = .000). Moreover, students in the conditions with a proactive teacher (M-proactive = 70.94, SD = 3.75; M-combi = 62.89, SD = 6.96) performed significantly better (F(3, 98) = 5.14, p = .002) compared to students in the reactive teacher condition (M-reactive = 49.39, SD = 5.04) and students in the control condition (M-control = 45.28, SD = 6.71). In addition, also knowledge about the inquiry skills of all students was improved after the intervention (Wilks' lambda = .25, F(1, 122) = 30.80, p = .000), with no differential impact of condition (F(3, 118) = 1.59, p > .05). Finally, students in the experimental, predefined teacher conditions reported to experience more differentiation (F(3, 123) = 6.45, p = .000), structure (Wilks' lambda = .76, F(6, 244) = 5.89, p = .000), and evaluated the intervention more positively (F(3, 123) = 3.34, p =.022) compared to students in the control condition. These results support the fact that technology should guide teachers to follow students' progression, and to be proactive, instead of only intervening when students ask help. The possibility to track student progression is an important indicator for teachers to make didactical decisions. The results indicate that implementing an innovative and learner-centred learning approach is only beneficial in combination with traditional, face-to-face interventions by the teachers.
