This study investigates the students’ ideas about an atom by asking them to describe an atom on a paper and pencil questionnaire. Students’ understanding of the structure of an atom, its constituents and their approximate locations, the size of an atom, and energy released by an atom are investigated. Analysis of responses was based on the phenomenographic method. The study does not attempt to develop a catalog of students' "misconceptions" of atoms. It explores how students describe atoms when they are presented with an open-ended question.

Materials developed by the Visual Quantum Mechanics project teach some basic ideas of quantum mechanics to high school and introductory college students by integrating hands-on activities and computer visualization. During field tests of the materials we obtained data concerning student understanding of some quantum concepts including potential energy diagrams, energy levels and spectra in atoms, energy bands in solids, wave functions and probability, and quantum tunneling. Data were collected from written responses of students structured interviews and a concept map.