Although the primary purpose of this study was to determine possible relationships between types of science programs used and intellectual development of sixth-grade students, a second purpose was to investigate possible effects of the sequence presentation of two programs. A third purpose was to investigate possible relationships between IQ scores and scores on Piaget-type tasks. Fifty-six sixth-grade students were assigned equally to two experimental groups. Group I studied an SCIS unit the first semester and a locally developed program the second semester. Experimental group II received the same instruction but in reverse order. On three different occasions each subject was interviewed and given five Piaget-type tasks. Chi-square analysis produced no significant difference for any task at the 0.05 level. Factors considered to have produced these results included: cognitive growth in areas not measured by the tasks; treatment time too brief; similarity of effect of the two programs; or similar teacher classroom behavior. A significant difference in favor of Group I was found on the results from the conservation of displacement volume task. Monotonic trend tasks to determine relationships between IQ scores and scores on tasks produced no significant relationship. (Author/EB)