This study attempted to determine at what grade levels children develop the ability to combine and control variables, the effect of the elementary science program on this development, and the relationship between a child's ability to control variables and his ability to form combinations of variables. (GS)

This is a National Trial Print of a unit on plants produced as a part of the Australian Science Education Project. The unit consists of an information booklet for students, a booklet for recording student data, and a teacher's guide. The material, designed for use with students in the upper elementary grades, takes from 15 to 20 forty-minute…