University students’ recognition of typical wave optics patterns

The recognition and distinction of typical interference and diffraction patterns are among the expected learning outcomes of studying wave optics. Previous studies have reported high school students’ difficulties with this task. In this study, we investigated university students’ ability to distinguish typical wave optics patterns obtained by the double slit, single slit, and diffraction grating. We also used eye tracking to obtain an insight into the distribution of students’ visual attention during the task. The results showed that university students had similar difficulties in recognizing wave optics patterns as high school students. They mostly struggled with identification of the double-slit interference patterns and diffraction grating patterns of monochromatic light while they were more successful in recognition of the diffraction pattern of white light on an optical grating and single-slit diffraction patterns. The eye-tracking data also revealed that students spent more time attending colourful than grey patterns in questions regarding diffraction of white light on an optical grating, thus suggesting that they were aware that the diffraction grating separates white light into colours. In questions regarding monochromatic light patterns, students overall mostly attended the single-slit diffraction pattern probably because of its distinct central maximum. Furthermore, the longer fixation duration for patterns compared to the text implies that students found it easier to extract information from the text than from the patterns. No prior research has compared the number of transitions during problem solving with the accuracy of the answers. In this study, we observed that students who incorrectly solved a task demonstrated a significantly higher number of gaze transitions between the question and the options, as well as among different options. The results of this study indicate that the recognition of typical wave optics patterns is also difficult for university students, thus suggesting that more attention should be paid to systematic observation and identification of key features of basic wave optics phenomena in lecture demonstrations and student laboratories.