This study investigated the effects of variations in the kinetic structure on science knowledge acquisition. According to the rationale of the kinetic structure theory, a communication having high structrue would facilitate greater knowledge acquisition than a presentation with low structure. To testify that hypothesis, a modified non-equivalent pretest posttest control group design was used. Four 10th grade classes (2 classes for each sex) were selected. On the topic of human digestive system, two tape recorded lessons differing in kinetic structure were developed. On n of two was high structure ($ar{B}_{1}$=0.56), and the other was low structrue ($ar{B}_{1}$=0.99) Results indicated that the high structure lesson did not show significantly higher score than the low structrue lesson(F=2.225, P<0.137). But when the data were analyzed by sex, only boy students showed the result that the high structure lesson had significantly higher score than the low structure lesson (F=4.785, P<0.009). The results of this study suggest that a high Structure communication will facilitate the science achievement in the case of boy students.