Sample

The sample of this study consisted of 78 first-year geology and geophysics students in the Faculty of Engineering in a large state university in western Turkey. Of these students, 20 were female and 58 were male (with a mean age of 20.9 with a standard deviation of 1.3). It was the only Faculty of Engineering that adopted a PBL curriculum in Turkey, and the geology and geophysics departments played an important role in the administration of the curriculum. The curriculum integrated the chemistry, mathematics and physics topics in two or three-week scenarios. The three-week scenario dealing with electromagnetism was the last one in the spring term. Therefore, the students were familiar with the instructional model. We can expect these students to be well-adapted to the needs of PBL. During the administration of the diagnostic electromagnetism test, the students were asked a question, rated on a ten-point scale, if they believed PBL was an effective approach to teach mechanics, electricity, magnetism, etc. The students selected a ten if the statement was very true to them and one if the statement was not at all true to them. The mean rating for the question was 5.6 with a standard deviation of 2.6. After at least one-year of PBL instruction, it seems that many students believed that PBL was not a very effective way of teaching physics topics.

The PBL scenario

The scenario used the Indiana University Cyclotron Facility as a context to teach the topics of electromagnetism including the magnetic field, due to a long straight current-carrying wire, magnetic force on electric charges, long straight current-carrying wires in a uniform magnetic field and electromagnetic induction. The facility is a multidisciplinary laboratory performing research and development in the areas of accelerator physics, nuclear physics, materials science and the medical applications of accelerators. One of the services provided by the facility is proton therapy, which uses a beam of protons to irradiate diseased tissue, most often in the treatment of cancer. It is a precise form of radiation treatment that minimizes damage to healthy tissue and surrounding organs (Midwest Proton Radiotherapy Institute, n.d.). The scenario, in which I was one of the co-authors, first gives some background information about the facility and states that for some reason the cyclotron stopped providing the proton beam necessary for the treatment. The students were required to state the problem, summarise the information given in the scenario, develop a hypothesis regarding the cause of the problem, and identify the learning issues to test their hypothesis. At the end of the scenario the students had an opportunity to solve some qualitative and quantitative problems in order to reinforce the electromagnetism ideas they learned in the scenario. Then, they were asked to create a concept map to improve the integration of these electromagnetism ideas with each other. The three-week scenario was supported by some direct instruction in electromagnetism after each PBL tutorial. During the administration of the diagnostic electromagnetism test, the students were asked questions, based on a ten-point scale, relating to whether they believed the scenario was effective in teaching electromagnetism. The mean rating for the question was 6.4 with a standard deviation of 2.3, suggesting that it was seen as a somewhat effective scenario by many students. The tutors in the PBL tutorials were experienced in the PBL approach and their area of study was either geology or geophysics. Therefore, they had limited knowledge of the basic ideas of electromagnetism.

Research instruments

The study included two research instruments, one for diagnosing students’ understanding of electromagnetism and another for assessing students’ motivational orientations and their use of different learning strategies for physics. The diagnostic magnetism test consisted of 16 five-option, multiple-choice questions drawn from the Conceptual Survey of Electricity and Magnetism (Maloney, et al., 2001), and Diagnostic Test of Students’ Ideas in Electromagnetism (Saglam & Millar, 2004). Of these 16 questions, two were about magnetic field due to current-carrying wire (Questions 2 and 10 in Table I), six were about magnetic force on electric charge (Questions 1, 5, 6, 7, 8 and 16 in Table I), three were about magnetic force on current-carrying wire (Questions 4, 14 and 15 in Table I), and five were about electromagnetic induction (Questions 3, 9, 11, 12 and 13 in Table I). The questions were translated into Turkish by the author of this article who had a satisfactory level of English. The questions were piloted with some civil engineering students, and necessary changes were made to improve clarity. The instrument collected information about the extent to which students believed that the PBL approach and the scenario used in the study were effective in teaching electromagnetism, as well as some demographic information. To prevent students from guessing and to reveal the misconceptions held by students, the students were given 100 points to divide between the answers for each question. If they were sure that one answer was correct, they gave it 100 points. If they could not decide between the answers, they were allowed to divide 100 points between the answers as they wished. If they had no idea about the question, they were told to divide the points equally between all the answers. In this study the information obtained from students’ use of the 100 points in each question was used to investigate students’ confidence in the basic ideas of electromagnetism.

The instrument used to assess students’ motivational orientations and their use of different learning strategies for physics was the Motivated Strategies for Learning Questionnaire (MSLQ) (Pintrich, Smith, Garcia, & McKeachie, 1991). The instrument is a self-reported, Likert-scaled instrument developed for college students. The motivation scales include three main components: (1) value components (intrinsic and extrinsic goal orientation, and task value); (2) expectancy components (control beliefs about learning, and self-efficacy): and (3) affective components (test anxiety). The learning strategies scales also consist of three components: (1) cognitive strategies components (rehearsal, elaboration, organization, and critical thinking); (2) metacognitive strategies components (planning, monitoring, and regulating strategies); and (3) resource management strategies components (managing time and study environment, effort management, peer learning, and help-seeking). Pintrich, Smith, Garcia and McKeachie (1993) report that the scale reliabilities of the MSLQ are robust, and it has a good factor structure. Buyukozturk, Akgun, Ozkahveci and Demirel (2004) adapted the MSLQ to Turkish. They report that “the Turkish version of the MSLQ can be utilized in experimental research to examine effects of various methods and applications, considering motivation and learning strategies. It can be also used in assessing to what extent students have motivation and use learning strategies at various educational institutions” (p. 235). The students were reminded that they should consider the physics content of the PBL scenario used in the study when they were responding to the MSLQ items.