This study investigates how collaborative knowledge construction within a discovery learning environment can be supported with tools aimed at supporting students’ proposition generation and testing processes. Sixty-six, fourth year pre-university education students, participated in a kinematics learning task. The instructional goal of the learning activity was to develop students’ understanding of one dimensional kinematics, the activity focused on collaborative inquiry and reasoning. All students completed a proposition list in which they could indicate their individual opinion about the truth value of specific propositions. The students were coupled into dyads and assigned to one of three conditions: 1) an expression builder (scratchpad), 2) a shared propositions table and 3) a control condition. Students in the scratchpad condition were provided with dropdown menu’s containing variables and relations. In the shared proposition table we combined students’ individual opinions about the truthvalue of a proposition into one shared proposition table. The shared proposition table displayed the truth-value, both students assigned to a particular proposition. Students in the control condition received no extra support related to propositions. Learning outcomes were assessed using an intuitive knowledge pre- and posttest. Students supported with the shared proposition table improved significantly from pre- to post-test and discussed significantly more alternative propositions.