 |
Asia-Pacific Forum
on Science Learning and Teaching, Volume 13, Issue 1, Article 4 (Jun., 2012) |
This study was conducted using quasi-experimental research design. Pretest-Post test non-equivalent control group design was applied in this study. The subjects were chosen from SSIII students of two secondary schools randomly selected from a population of six Senior Secondary Schools in Otukpo Urban of Benue state in Nigeria.
This study was applied to 124 SSIII physics students, of which 63 were in the experimental group and 61 were in control group. In the control group, the convectional teaching method (e.g. lecture method) was applied, whereas in the experimental group 4E learning cycle method was applied. The procedures in the experimental group were as follows.
Exploration: This involves laboratory activities. In this phase, the students are at the centre of the action as they collect data to solve the problem. For instance, students were asked to attach a metal bob to one end of the string from a rigid support and pull the mass slightly to one side of its equilibrium position and release it. The students were asked to observe the to and fro movement of the bob about the rest position and take the time taken for complete oscillation.
Explanation: In this stage, the teacher leads the students to relate the results of the activity and/or topic to other topics already understood. The teacher discusses the activities or the observations of the students with them. That is, the teacher will share his insights, knowledge and experience with the students by asking probing questions that permit the students to move toward scientifically accepted explanations. The teacher also introduces new vocabulary, phrases or sentences to label what the students have already identified.
Expansion: This stage requires that the students engage in the application of scientific knowledge gained. The creative ability of the students is important in this stage. The teacher gives the students the new information that will enable them expand what they have learned in the earlier stages of the learning cycle. The teacher poses problems that the students will solve by applying what they have learned. For instance, the students were asked to put some iron fillings into a test tube until the test tube can stand erect in a liquid contained in a beaker with about half of the length of the test tube submerged in the liquid. They were also asked to depress the test tube a few centimeters into the liquid and observe the up and down motion of the loaded test-tube and note the regularity of the motion.
Evaluation: This is an important component during which students reflect on the topics studied. It was an ongoing process in every stage of the cycle. Evaluation was formative at the every stage of the cycle and summative at the end of the teaching process.In both groups the lessons were taught by the research assistants supervised by the researcher.
The four steps are diagrammatically represented in figure 1.Figure 1. Four-phase Learning Cycle
In this study, data were gathered using Simple Harmonic Motion Achievement Test (SHMAT). This test was developed and validated by the researcher to identify students understanding of simple harmonic motion. SHMAT consisted of 10 short essay questions. In developing SHMAT, research findings reported in the literature were utilized and the objectives of the subject matter were considered. The SHMAT was trial tested with 50 students in SSIII of different school and the responses were used to calculate the reliability of SHMAT using Cronbach Alpha since the scoring was not dichotomously done. The reliability was found to be 0.76. Similarly, coefficient of stability was also found to be 0.98 using Pearson product moment correlation coefficient. The reliability indices mentioned above were found to be high to adjudge the instrument reliable. The validity of the test was checked by two experienced physics teachers and two experts in Measurement and Evaluation. They were requested to check if there was any ambiguity in the questions and whether the questions addressed the purpose of the study.
The scoring of the students’ responses in SHMAT in both Pretest and Post test was done by assigning each response 2, 1 or 0 point. That is, students’ justifications and explanations as they answer the questions on concepts related to SHM will be scored as follows. (ALPS, 2007).
- Sound understanding or complete response (2mks). This response indicates that students seem to have acquired an integrated scientific perspective. They are able to restructure their ideas and give a coherent explanation of the phenomenon. For instance in explaining simple harmonic motion, complete response will be “simple harmonic motion is an oscillatory motion in a straight line whose acceleration is directed towards a fixed-point (equilibrium position) and the acceleration is proportional to the displacement from the fixed point”
- Partial understanding or incomplete response (Imk). The response indicates that students seem to have a partial knowledge of the concept or phenomenon. That is, ideas are not verbalized in an integrated way, but some kind of understanding is evident for instance, simple harmonic motion is an oscillatory motion in a straight line whose acceleration is directed towards a fixed point or the acceleration is proportional to the displacement from the fixed point only.
- Alternative understanding or alternative conception (Omk). In this, students give just one simplistic incorrect view point. That is, students give linear explanation rather than see a number of factors as being responsible for the phenomenon. This response indicates lack of understanding about the concept or phenomenon. On the basis of 2, 1, or 0, the frequency of responses as well as the percentages will be determined in order to determine the level of understanding
Two instructional approaches were employed for this study. The first approach was the use of four-phase learning cycle method while the second was the use of conventional lecture method. The two approaches were the same in terms of content, basic instructional objectives and mode of evaluation. They differ in terms of instructional activities. The four-phase learning cycle method was based on guided inquiry learning derived from constructivist theory. That is, the students were led to elicit ideas and generate explanations and interpretations of concepts in SHM.
The four-phase learning cycle method namely exploration, explanation, expansion and evaluation was applied to experimental group, while the lecture method approach was applied to the control group. Before the actual experiment, two research assistants (regular physics teachers) were coordinated on the use of the experimental treatments and the marking scheme and the lesson notes. This exercise provided the researcher with the opportunity of identifying the background knowledge of research assistants on the research procedures. The exercise also enabled the researcher to determine the research assistants knowledge of the subject matter and also to ensure that they do not deviate from the steps of the instruction.
After this exercise, the research assistants and the researcher administered the pretest to both groups at the end of which the treatment started. The treatment in both groups lasted for four weeks and in each week, two double periods of 80 minutes were used making a total of eight double periods for four weeks. At the end of the treatment, the research assistants administered the posttest to the groups after two days of revision. During the revision exercise, the students were requested to go through the activities and their notes and seek any clarification where necessary from the research assistants. Data, obtained from the pretest and posttest, were used to answer the research questions using frequency and percentage and test the hypothesis using chi squared statistic. The Chi-squared statistics was adopted because the measurement was on nominal scale.
