Katie Clegg – Thesis Defense on Aug. 4
ORAL THESIS DEFENSE
MST Candidate: Katie Clegg
Thesis Advisor: Molly Schauffler
Submitted in Partial Fulfillment of the
Requirements for the Degree of
Master of Science in Teaching
August, 2010
Wednesday, Aug. 4, 2010
1:00 pm
102 Bennett Hall
ASSESSING MIDDLE AND HIGH SCHOOL STUDENTS’ CONCEPTUAL UNDERSTANDING
ABOUT PHOTOSYNTHESIS
This study investigated two major research questions regarding photosynthesis education. The first research question was, to what extent do middle and high school students understand the following five major concepts about photosynthesis and cellular respiration before, and after instruction: (a) chlorophyll is necessary for photosynthesis, (b) light is the energy source for photosynthesis, (c) carbon dioxide from the atmosphere is the carbon source for plants, (d) plants undergo cellular respiration, and (e) cellular respiration occurs within all cells. The second research question was, does there appear to be a relationship between how well teachers are able to predict their students’ responses as a class on the post-survey and the class’s normalized gain? Is there a similar positive correlation between teachers’ pedagogical content knowledge (PCK) and student gains in understanding when teaching photosynthesis, as found in physical science?
To test these research questions, pre- and post-surveys were administered to five middle school and four high school classes in Maine about photosynthesis (n = 335 students; n = 9 teachers). Teachers answered a pre-survey regarding materials they use, what concepts they cover, and completed a post-survey that asked teachers to predict their students’ responses to the post-survey. All surveys were administered between September 2008 and April 2009.
This study has uncovered two main findings. First, middle and high school students in this study lacked the conceptual knowledge about photosynthesis that is required by national and state science standards. This finding suggests that middle and high school students in this study did not learn the concepts that they are expected to understand as outlined in the science standards, and that middle school students are not entering high school with an accurate conceptual understanding about photosynthesis. Second, classes with gains in understanding after instruction were more likely to be taught by teachers who had high PCK scores (matched predictions). This was especially evident in questions that assessed concepts in which students have been shown to have deep-rooted misconceptions. Based on these two findings, I propose suggestions for future research and recommendations for the classroom.