The purpose of this study was to determine the relative effectiveness of three different types of visual devices in an instructional program designed to teach an understanding of selected theoretical science concepts to elementary school children. The visual devices were prepared using Bruner's three modes of representation (enactive, iconic, and symbolic) as guides; the visual devices differed in levels of abstraction. Six classes, selected from an available population of 19 classes, were randomly assigned two to each treatment. Seven 25-minute classes were given by the principal investigator to each class. A paper and pencil test (Test of Introductory Electrostatics) and a competency test (individual interview and demonstrations) were used as pre- and posttests. The preparation and validation of the tests were major aspects of the study. It was concluded that it is reasonable to teach the basic concepts of electrostatics to fourth-grade students. Students at this grade level are capable of working with theoretical concepts at the comprehension and application levels. Students do find models useful in explaining phenomena, and model building should be a skill developed in an elementary school science curriculum. (Author/BR)