Developing and validating a model of students’ understanding of wave properties of light
Educational chemistry research on student learning of light wave properties.
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- [00:00:01.420]Hi, I'm Simreen Kaur
- [00:00:03.667]and this summer I worked on a very interesting project with the moon group from the Department of chemistry at UNL, for which Im going to present the poster now
- [00:00:11.862]This project is aimed on developing a model of students' understanding of wave properties of light
- [00:00:20.120]To introduce you to the project, I would like to zoom on to this figure, which explains the process of student learning in a cyclical form, consisting of cognition, observation and interpretation.
- [00:00:33.255]The area that we worked on this summer is linked between cognition and observation.
- [00:00:38.858]Using our approach we made a model of student understanding of wave behavior of light that could generate a qualitative evidence of students' reasoning, called construct maps. Items and item responses were developed from the construct maps and help provide evidence of the students knowledge to researchers and educators.
- [00:00:57.483]The research questions framing this study are: -'How do students reason the behavior of light in the context of experiments such as the double slit and How can we can quantify students understanding of these concepts using a scale?
- [00:01:13.532]To answer these research questions data was collected from a total of 31 students from different years of chemistry. This data was qualitative and collected in interviews.
- [00:01:22.854]Data collection was followed by data analysis- where the interview transcripts were analyzed to identify themes.
- [00:01:30.693]Such as, in item 1, where the student was shown a continuous light stimulation and asked why they saw a specific pattern of light and dark coencentric circles, a lot of students who were not familiar with light matter studies told that it was as a result of light being blocked, showing dark regions or allowed to pass through freely, showing light regions.
- [00:01:56.113]This theme was observed throughout a number of students and hence was used to mark Level 1 on the construct map, which is a preliminary level of understanding.
- [00:02:08.869]Data Analysis is followed by Model Generation in which the identified themes were translated into construct maps and then into items.
- [00:02:22.085]Model revision was then followed by revision of the items and construct maps based on the coding performed.
- [00:02:29.768]Coding was the process where we marked specific sentences in the student transcripts and tried to match them to the item responses and construct map.
- [00:02:40.159]Data analysis, model generation, and model revision is an iterative process which means each step continually informs the other steps.
- [00:02:51.944]Moving on to the results, here I have put the student responses on the left , pointing to the corresponding item responses which also match with the construct map levels on the right
- [00:03:11.447]I have taken the example of Item 7 here to demonstrate the results.
- [00:03:16.201]In this Item, the students were shown two light stimulations of red and blue light through a double slit barrier and asked why they saw a different pattern for both of them, as illustrated in the figures given here.
- [00:03:28.557]In the first student response, the student in their transcript answers that the red figure has a bigger
wave so it could fit more colors in, which matches item response a, as it states that red light has a large wavelength which causes the it illuminated regions to take up more space.
- [00:03:50.382]This item and student response belong to level 1 of the construct map because the student demonstrates the understanding that longer wavelengths result in light taking up more space on the screen.
- [00:04:01.927]The second students says that the red light's wavelength is longer and has more spread out crests and troughs , which points to item response b, and the student is at level 2, because it marks when the student understands that light can add or cancel out due to the crests and troughs in it.
- [00:04:23.626]Since the third student says that the frequency of red light is lower so it is not moving fast enough and causes lesser interaction,this response match item response c, which states a similar reasoning -the red light has lower frequency and therefore takes a longer time for interference resulting in larger regions on the screen.
- [00:04:42.465]This response coded as level 3 since the student seems to understand that the frequency of light is related to the time associated.
- [00:04:53.184]In the 4th example here, the student says that there were lesser iterations in the stimulation with red light which was matched with item response d, and level 4, as the student shows the understanding that the interference gives rise to a specific repeating pattern of light which is dependent on the number of instances.
- [00:05:15.592]So is was how the coding for this project was performed and the codes that we obtained from all the students showed evidently that student understanding of light matter interactions varies in sophistication.
- [00:05:34.899]This is a more holistic approach and helps place students’ understanding along a broad continuum , instead of just terming it as correct or incorrect and helps researchers and educators understand student learning better
- [00:05:52.680]In the future, the items and construct maps designed in this project must be piloted with a wider sample of students.
- [00:06:00.578]Furthermore, Student responses to the item will inform revisions to the construct maps and to refining a learning progression on students’ understanding of light-matter interactions, which can then shape curricular reform.
- [00:06:16.233]After studying the results of this research, we can study how the sophistication changes over years of studying chemistry and what factors may be affecting the change.
- [00:06:27.216]I have also listed here the references that I have used in the project here.
- [00:06:33.413]Lastly I would like the moon group for helping me in this project and giving me this great opportunity.
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