This paper discussed the use of structured observations as a research strategy in two recently completed studies that investigated students thought processes and behaviors in a microcomputer-based laboratory (MBL) environment and in other instrument-based laboratory environments. In the first study, students' behaviors and thought processes were investigated as they performed an acid-based neutralization. Eight students were divided into two groups and performed the same tasks but used different instruments. In the second study, students thought processes were investigated as they performed a series of acid-base titrations using either a microcomputer-interfaced pH probe, a stand alone pH meter, or a chemical indicator to detect changes in the pH of the chemical system. Fifteen students were divided among the groups. In both studies, the students were encouraged to think aloud as they were videotaped performing laboratory activities, and were sometimes asked to clarify and explain their expressed thoughts. The videotapes were then analyzed to determine how well the students' actions corresponded to their self-reported thought-processes. Structured observations recorded provide data about how students interact both with the instrumentation of the treatment and with the cognitive tasks of the treatment. (Author/MLB)