Effect of a research-based instructional intervention on student learning of the concept of gravity: Immediate and delayed achievement of fourth-grade students

The study was designed to determine the effect of an organized, conceptually-oriented set of lessons involving the concept of gravity on the immediate and delayed achievement of fourth-grade students. Two demographically similar schools were selected for the study, with two "Treatment" classes in one school and two "Comparison" classes in the other school. The sample included 91 fourth-grade students in the four classes who were taught the concept of gravity for two weeks involving three 30-minute lessons per week. The Treatment Group teachers taught the concept of gravity using six prepared lessons. Within the same time frame, Comparison Group teachers used the text book as a guide to teach six lessons on gravity. At the end of the two weeks of lessons on gravity, a 20-question posttest was administered to each class. After another three weeks, a delayed posttest was given. Results of the Cronbach's alpha procedure showed that the two tests were reliable and appropriate for use with fourth grade students. Results of a student opinion question concerning how much the students thought they learned about gravity during the two week period showed that the students in the Treatment Group had more positive answers concerning their learning than the Comparison Group students. The ANOVA results confirmed there was no significant interaction between gender, socio-economic status, reading ability, or ethnicity and the treatment. An independent t-test found that the mean differences between the Treatment Group and Comparison Group scores on both the posttest and delayed posttest were large (4.6 and 5.2). The Treatment Group results were higher, which points to a greater retention of the concept of gravity over time by students. Cohen's Effect Size resulted in a large effect for the posttest and delayed posttest (1.8 and 2.3), suggesting that the intervention may have had a significant effect on student learning of the concept of gravity. This study suggested that having well organized, conceptually-oriented instructional lessons may assist the teacher in improving student learning of scientific concepts and aid in the retention of the concepts over time.