STUDENTS PRECONCEPTIONS OF THE NATURE OF GASES

A total of 1098 students, from second graders to university chemistry students, drew representations of highly magnified views of air at 1.0 atmosphere of pressure and at 0.5 atmosphere of pressure. The drawings were classified and the authors inferred from them a relatively limited number of preconceptions of the nature of gases. Several major trends occurred in the frequencies of these infer-red preconceptions held at different grade levels. The majority of the drawings that were not in fairly close agreement with atomic theory seemed to reflect one or more of the following misconceptions: (a) air is a continuous (nonparticulate) substance, (b) gas behavior is similar to liquid behavior, and (c) there is relatively little space between gas particles. The number of drawings that gave evidence of particulate views ranged from 8% for Grades 2-4 to 85% for university chemistry students. However, 33% of the university students' drawings showed highly packed particles, and only 37% showed particles in an approximately correct geometrical distribution. The authors suggest a technique for promoting conceptual change among students who possess alternative views of the nature of gases.