Modeling Atoms & Molecules: A New Lesson for Upper Elementary & Middle School Students

Abstract

Our experiences with AP Biology students suggested that many had difficulty grasping even a rudimentary understanding of basic biological chemistry. Consequently, a great deal of time was spent, initially, to address this deficiency. One of the hands-on approaches developed for a simple one-hour lab was the use of balloons and BB's, with supportive demonstrations, to help students visualize the simplest concepts of atomic structure. Unlike other methods (e.g. gumdrops and toothpicks), our models present a 3D visualization of the 2D Bohr model format. Later, in lecture, the quantum theory of electrons in 3D orbitals within valence shells was developed. The single most important aspect of this method is a dynamic view of how electrons spinning in orbitals determine much of the spatial structure and, consequently, function of atoms and molecules. Given the elementary nature of this lesson, we thought it might be useful to upper elementary and middle school students. Moreover, we anticipated that teachers of those students would become so confident using this method that they would incorporate atomic/molecular explanations into other, formerly descriptive, lessons. During 1992-93, the lesson was given to 86 fifth-grade science students at a local elementary school, prior to a unit on freshwater, estuary and marine ecosystems. Highly favorable responses from students in these trials and in subsequent workshops with elementary and middle school teachers and their students gave us confidence to submit the following lesson for a more general audience.