Identifying student and teacher difficulties in interpreting atomic spectra using a quantum model of emission and absorption of radiation

Abstract

Our study sets out to identify the difficulties that high school students, teachers, and university students encounter when trying to explain atomic spectra. To do so, we identify the key concepts that any quantum model for the emission and absorption of electromagnetic radiation must include to account for the gas spectra and we then design two questionnaires, one for teachers and the other for students. By analyzing the responses, we conclude that (i) teachers lack a quantum model for the emission and absorption of electromagnetic radiation capable of explaining the spectra, (ii) teachers and students share the same difficulties, and (iii) these difficulties concern the model of the atom, the model of radiation, and the model of the interaction between them.

Problem-based structure for a teaching-learning sequence to overcome students’ difficulties when learning about atomic spectra

“…The percentage of answers left blank by control students is particularly high compared to an insignificant percentage in the experimental group. The lack of answers, also detected by other previous studies [15,19], can be attributed to the lack of an explanatory model that helps them find and/or justify their answers. Regarding the difficulties related to the key ideas, we observe that the percentage of difficulties detected in the experimental students is lower in all cases, except for difficulty B3 for question Q3 that remains constant.…”

“…With regard to the students' difficulties on the subject, a review of previous research has been conducted [49,50]. Moreover, preliminary research was conducted on the students' difficulties in relation to the objectives defined in the TLS [19].…”

“…To evaluate the learning achievement reached by the experimental and control students, a pretest and post-test were designed with very similar open questions. The posttest questions, that have already been validated in another study [19], are attached as the Appendix. It includes three questions:…”

“…In a previous paper [19], we established the key concepts (KC) that any quantum model of emission and absorption of electromagnetic radiation should consider in order to explain gas spectra in quantum physics introductory courses (see Table I). Moreover, we identified the main difficulties that high school students, university physics students, and high school teachers had regarding this issue.…”

“…It should be emphasized that, although these KCs refer to the emission and absorption of radiation and they can be considered to be typical of quantum physics introductory TABLE I. Key concepts that should be considered in any quantum model of emission and absorption of electromagnetic radiation to explain the gas spectra [19]. KC1 (atomic model).…”