As more concerns have been raised about withholding answers during science teaching, this article argues for a need to detach 'withholding answers' from 'hands-on' investigation tasks. The present study examined students' learning of light-related content through three conditions: 'hands-on' + no 'withholding' (hands-on only: HO), 'hands-on' + 'withholding' (hands-on investigation with answers withheld: HOW), and no 'hands-on' + no 'withholding' (direction instruction: DI). Students were assessed in terms of how well they (1) knew the content taught in class; (2) reasoned with the learned content; and (3) applied the learned content to real-life situations. Nine classes of students at 4th and 5th grades, N = 136 in total, were randomly assigned to one of the three conditions. ANCOVA results showed that students in the hands-on only condition reasoned significantly better than those in the other two conditions. Students "in this condition" also seemed to know the content fairly better although the advance was not significant. Students in all three conditions did not show a statistically significant difference in their ability to apply the learned content to real-life situations. The findings from this study provide "important contributions regarding" issues relating to withholding answers during guided scientific inquiry.