An instructional model based on a learning cycle including correlation, analysis, and generalization (CAG) was developed and applied to design an instructional module for grade 8 students in Taiwan, Republic of China. The CAG model was based on Piagetian theory and a concept model (Pella, 1975). The module developed for heat and temperature was administered to test its effects by comparing its use with the same unit in the New Physical Science Curriculum (NPSC). The population was comprised of classes selected from four types of schools. The treatments given were instructional materials, teacher training, pretest, and posttest. Students who were in the experimental group received a copy of the CAG module. Students who were in the control group used the NPSC (1988) material. The major findings were presented as follows: (1) the CAG module tended to improve science learning in an effective way; (2) academic ability and reasoning skills of students were related significantly to achievement; (3) concrete written materials tended to have a positive impact on the science achievement for eighth-grade students; (4) Piagetian logical thinking was found to be a significant predictor for science achievement; and (5) several student misconceptions related to the topics were detected in the tests and interview analyses. (CW)