Abstract: This study aimed to determine the effectiveness of structured and unstructured laboratory approaches on the scientific comprehension and performance skills of Third Year High School students in one of the private secondary schools in Central Philippines towards Chemistry Subject. Quasi-experimental design with matched pairs and post-test only control and experimental groups was employed to 100 respondents who were assessed through comprehensive tests on the physical and chemical properties of matter and performance skill evaluations using teacher-made rubrics. T-test and Pearson Product Moment Correlation were applied at the 0.05 level of significance as the applied statistical tools. Findings revealed that students exposed to the unstructured laboratory approach achieved higher mean scores in scientific comprehension compared to those under the structured approach, both interpreted as satisfactory. Performance skills were also superior in the unstructured group, interpreted as Highly Skilled while the structures group was Highly Skilled. There were significant differences found in both comprehension and performance skills between the two approaches, endorsing the unstructured method. Additionally, comprehension and performance skills under both approaches showed strong positive correlation which indicated that the cognitive and psychomotor domains complement each other in laboratory learning. The results suggest that unstructured laboratory activities promote stronger independence, critical thinking, and skill acquisition, underscoring their academic significance in Chemistry instruction. Recommendations involve organizational support for unstructured laboratory manuals, assimilation of lecture and laboratory schedules, and focus on safety and proactive student participation.
LYDIA F. GORRICETA* (Wed,) studied this question.