Despite the importance placed on laboratory work in the undergraduate chemistry curriculum, there have been few research studies showing that laboratory experiments are an effective vehicle for promoting understanding of chemistry. Laboratory activities that are inquiry-based have been reported to have potential for improving the pedagogical value of laboratory work. This study compared the performance of general chemistry laboratory students who used the standard laboratory report format to the performance of students who used the Science Writing Heuristic (SWH) format on a lecture examination problem and on a laboratory practical examination task involving physical equilibrium. The standard laboratory reports had title, purpose, procedure, data and observations, calculations and graphs, and discussion sections. The SWH reports had beginning questions and ideas, tests and procedures, observations, claims, evidence, and reflection sections. Students in the SWH sections exhibited a better understanding of ...