This is the second of two closely related articles (Paper I and Paper II) that together illustrate how research in physics education has helped guide the design of instruction that has proved effective in improving student understanding of atomic spectroscopy. Most of the more than 1000 students who participated in this four-year investigation were science majors enrolled in the introductory calculus-based physics course at the University of Washington (UW) in Seattle, WA, USA. The others included graduate and undergraduate teaching assistants at UW and physics majors in introductory and advanced physics courses at the University of Zagreb, Zagreb, Croatia. About half of the latter group were preservice high school physics teachers. Paper I describes how several conceptual and reasoning difficulties were identified among university students as they tried to relate a discrete line spectrum to the energy levels of atoms in a light source. This second article (Paper II) illustrates how findings from this research informed the development of a tutorial that led to improvement in student understanding of atomic emission spectra.
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During our investigation, we also identified student difficulties directly related to the experimental equipment used to produce and observe emission line spectra. These complications and the development of a tutorial to addresses them will be discussed in a future article.
For example, some students treated all the shades of green as a single distinct color. They then said that the number of energy levels was the same as the number of colors in the spectrum.
For Questions 2 and 3, students are shown a portion of an atomic spectra consisting of 11 lines and asked two questions. Question 2: Which of the line(s) correspond to a transition between the two closest atomic energy levels? Question 3: What is the minimum number of energy levels required to produce the spectra consisting of 11 lines?
The UW Honors course consists of students enrolled in a university honors program. Students in this section are interested in taking a physics course that goes into greater depth than do the regular sections. They tend to be strong students with good preparation, although the percentage of physics majors is essentially the same as in the regular course sections.
Tutorial questions are a standard part of the examinations in the introductory calculus-based physics courses at UW. Thus, the number of post-test questions that we can ask on a single exam is limited and the questions need to vary from exam to exam. Since the results have been similar from one quarter to another and from one class to another, our assessment of student understanding is constructed from a variety of questions given over multiple years to different students.
The juniors in Croatia and beginning physics graduate students at UW are very comparable. The coursework that has been taken by both groups is similar.
A breakdown by course ranking for students in the UW Honors section is not given since the number of students is relatively small. Moreover, the students in the UW Honors course generally are regarded as representing the best performing students in the regular sections of the introductory course.
The results from the Croatian junior level course and the UW TAs are consistent with this finding since these courses tend to draw on students who have done well in the introductory course.
The “clicker” questions were short multiple-choice questions posed by the instructor at various times during each lecture. Each student had a small electronic device (“clicker”) that he or she could use to transmit responses to a central computer. Students were asked to discuss their ideas with one another before choosing their answers.
