 |
Asia-Pacific Forum
on Science Learning and Teaching, Volume 9, Issue 2, Article 2
(Dec., 2008) |
This study is conducted with 78 pre-service science teacher including 2 groups, the control and experimental, at the third grade student level teachers of Science Education Department at Gazi University in the Faculty of Education. The control group consists of 40 pre-service science teachers including 21 women and 19 men, and the experimental group consist of 38 candidate teachers including 27 women and 11 men. In addition, the study was conducted within the course Science Laboratory Application during 2007–2008 Spring semester. Group work and demonstrative experiments based on conceptual change approach were randomly applied on selected pre-service science teachers in the experimental group during course sessions about photosynthesis and respiration in plants. Randomly selected pre-service teachers in the control group handled the subject in traditional methods.
“Photosynthesis and respiration in plants concept test”
Photosynthesis and respiration in plants concept test which was developed by Kose (2004) was given to pre-service teachers. Questions in this test were constructed with translation of literature and the results of the questionnaire and interviews which were held by Kose (2004). The 20-item multiple choice test has two phases. In the first phase of the test, pre-service teachers’ content knowledge was assessed. In the second phase, clarity of that knowledge that pre-service teachers had was assessed. Also, the validity of concept test was evaluated. The reliability of concept test was calculated as alpha=0.78.
In the first stage of the test there were multiple choice questions that contained common misconceptions determined by interviews and the written examination. In the second stage of the test, the underlying reasons of those decisions were discovered by asking questions like, “the reason why I chose this choice is that” with multiple choice answers. In multiple choice reasons there was a right answer as well as misconceptions that pre-service teachers have. In the grading process of the photosynthesis and respiration in plants concept test, the right choice-right reason is valued as 3 points, the wrong choice right reason is valued as 2 points, the right choice wrong reason is valued as 1 point, and the wrong choice-wrong reason is valued at 0 points.
Conceptual testing of photosynthesis and respiration consists of two stages. These two stage tests have been extensively used by many researchers for fifteen years in different fields of science (Haslam and Treagust, 1987; Odom and Barrow, 1995). Tests consisting of two stages are different from multiple choice tests because of the second stage component. The second stage of the test could be either an interview or a form containing student misconceptions derived from literature investigation based on the students’ misconceptions. There are studies that two-stage tests provide important conveniences to determine misconceptions of students and their reasons (Haslam and Treagust, 1987; Odom and Barrow, 1995).
This study was conducted on science education pre-service teachers while they are studying photosynthesis and respiration in plantsduring a science laboratory application course. The experimental group used group work and demonstrative experiments based on the conceptual change approach. The control group took the traditional course. In the control group, researchers want pre-service teachers, who will teach the subject, not to prepare extra materials beforehand and to present the content using a traditional approach. While preparing group work and demonstrative experiments based on conceptual change approach, it was necessary that students’ misconceptions on the related subject should be considered. Moreover, the minimization or elimination of those misconceptions was the goal. The students were expected to realise the subject and orient demonstrative experiments and group work. Pre-service teachers, who would instruct the subject in the experimental group, should prepare extra materials and demonstrative experiments, as well as presenting theoretical information about photosynthesis and respiration in plants.
In experimental group, pre-service teachers who would teach the photosynthesis and respiration in plants were prepared to experiment set-ups on questions like: “Does sunlight affect the growth of plant?”, “Do plants transpire?”, “Do plants respire?”, “Does air have any effect on plants?”, “Does respiration continues on day and night?”, “Does light have effect on photosynthesis?”, “understanding fermentation”, “understanding the factors that effect photosynthesis”, “the structure of chloroplast, mitochondria and their differences”. The pre-service teachers show and present the experiments that they prepared beforehand. The applications took 3 weeks at the beginning of the 2007–2008 Spring semester. The photosynthesis and respiration in plants concept test was conducted on both the experimental and control groups. Four weeks after the application of the pre-test, post tests were conducted to both the experimental and control groups.
In this study, group works and demonstrative experiments based on the conceptual change approach were used in the experimental group. On the other hand, the control group used traditional approaches. In order to assess whether there was a significant difference among control and experimental group, and within those groups knowledge of photosynthesis and respiration in plants concept test, the t-test was used. An independent sample t-test was conducted to understand the difference among the dependent variable of experimental and control group and whether it is significant in 95%-99% confidence interval or not. The paired sample t-test was conducted in the experimental and control group to understand the difference before and after treatment.
Moreover, in order to achieve homogeneity of groups before treatment results of independent sample t-test for each group was compared in addition to an analysis and comparison of these mean scores, standard deviations, t values and p values.
