This study, part of an instructional development project, explores the effects of three different representations of functional algorithms in an introductory chemistry laboratory. Intact classes were randomly assigned to a flowchart, list, or standard prose representation of the procedures (algorithms). At the completion of 11 laboratory sessions, data were collected on critical thinking ability as measured by the Watson-Glaser Critical Thinking Appraisal. Laboratory instructors' estimates of completion time for each lab were obtained. Analysis indicates that mode of representation produces no significant difference between groups on critical thinking ability. However, a differential effect in laboratory completion times was found. Appended is a sample of each type of functional algorithm employed. (STS)