Educational Research Institute of America (ERIA) conducted a 12-week pretest-posttest study to assess the effectiveness of an instructional model of the HMH Science Dimensions program. Study participants included 139 Grade 7 and 8 students and two teachers from two different schools in two different states. The pretests and posttests were developed for the module. Results indicated the average gain scores for the total group of 139 students were statistically significant. The results showed the gain scores for the low- and high-achieving pretest scoring groups also increased statistically significantly.