What students learn from hands on activities
The ability to design and interpret controlled experiments is an important scientific process skill and a common objective of science standards. Numerous intervention studies have investigated how the control of variables strategy (CVS) can be introduced to students. However, a meta analysis of 72 intervention studies found that the opportunity to train CVS skills with hands on tasks (g 0.59) did not lead to better acquisition of CVS relative to interventions without a hands on component (g 0.74) We conducted an intervention study in which we investigated the differential effects of hands on and paper and pencil training tasks on 161 eighth grade students' achievement. CVS was demonstrated to all students before they were grouped into a hands on or a paper and pencil training condition. In both training conditions, students designed and interpreted experiments about which variables influence the force of electromagnets. Students in the hands on group interacted with physical equipment while students in the paper and pencil group planned experiments using sketches and interpreted the outcome of experiments presented in photographs. We found no general advantage or disadvantage of hands on tasks, as both groups did equally well on CVS and content knowledge tests. However, hands on students outperformed paper and pencil students on a hands on test identical to the training tasks, whereas the paper and pencil students outperformed hands on students on a science fair poster evaluation task similar to the paper and pencil training. In summary, students learned task specific procedural knowledge, but they did not acquire a deeper conceptual understanding of CVS or the content domain as a function of type of training. Implications for instruction and assessment are discussed. (c) 2016 Wiley Periodicals, Inc. J Res Sci Teach 53:980 1002, 2016