This study was conducted to find the effect of discovery approach on students'

critical thinking skills and its relation to achievement in General Science.

The study was conducted at Macario B. Asistio Sr., High School, Unit 1, Division of City Schools, Caloocan during the second grading period of the school year 1999. 2000 Four intact classes of first year students were used. There were 30 matched pairs where they were matched according to age, sex, mental ability and protest scores in critical thinking. Only those included in the matched pairs were considered in the analysis of data. The experimental group was subjected to discovery approach while the control group to the conventional method.

The critical thinking skills test used in this study was the Gutierrez Tent on Critical Thinking (GTCT). The achievement test items were selected from the previous years' achievement tests given by the Division of City Schools, Caloocan.

The t-test for correlated samples was used to determine the significant difference in the means in critical thinking skills of pretest and posttest scores. The same test was used to determine the significant difference in the mean gain scores in critical thinking skills of the experimental and the control group. The t-test for independent samples was used to determine the significant difference of the mean posttest scores of the experimental and control groups. Pearson Product Moment Correlation Coefficient, r was used to determine if there is a positive relationship between critical thinking skills and achievement in General Science.

Findings revealed that students taught using discovery approach improved better in critical thinking skills than those taught using conventional method as indicated by a significantly higher critical thinking skills mean gain. Furthermore, it was also found that critical thinking skills is positively related to achievement in General Science.