This study examines the effectiveness of a designed student-centered instruction in improving students’ understanding of acids and bases. The instruction was designed based on constructivist, inquiry and context-based approaches. A triangulation mixed methods design was employed included a quasi-experiment with pretest and posttest. The participats were two classes of senior high school students from Indonesia, chosen as treatment and control groups and a class of grade 10 Super Science High School students from Japan. Analysis of covariance followed by an unpaired sample t-test for mean gain scores were performed to analyze the Indonesian students’ scores on the achievement test and a normalized gain score was calculated for Japanese students’ achievement. A descriptive analysis was performed to analyze the responses on both self-evaluation and open-ended questionnaires. Results of this study indicate that the designed student-centered instruction group significantly outperformed the traditional group in understanding of acids and bases. Analysis of students’ responses on the questionnaires show that most of the students (97%) in the treatment goup were actively involved in the unit, enjoyed working with hands-on activities, and were very interested in participating in the activities. The students also felt their understandings of the concepts have improved. This study was also effective when it was implemented in Super Science High School students in Japan and most of the students (97%) enjoyed the teaching and learning process and most of them (80%) felt that their understandings of the concepts had improved.This study has implications for both Indonesian and Japanese senior high schools.
Key words: designed student-centered instruction, effectiveness, constructivist, inquiry, context-based approach, achievement, perceptions
INTRODUCTION
Results of the Third International Mathematics and Science Study (TIMSS) and the Programme for International Student Assessment (PISA) indicate that Indonesian students’ performance on mathematics and science is relatively poor compared to those of other countries, including Japan (Lemke et al., 2004; Gonzales, 2000). This reality is one of the impetuses of the Indonesian government to reform science education. The essence of the reform program lies in a learning paradigm, educational decentralisation and competence-based curriculum (Sidi, 2008). One of the government’s reform initiatives was to launch a new curriculum in 2006. The new 2006 curriculum suggests that pedagogy implemented in all school levels should be student-centered with an emphasis on creativity, competency, life skills and hands-on experiences (BSNP, 2007). There have been some efforts to realize this curriculum expectation. For example, the educational community and reseachers have introduced a contextual teaching and learning (CTL) approach and an active, creative and enjoyable teaching and learning approach (in the Indonesian language it is called PAKEM) for changing school instruction. Such reform efforts, however, are rare for high school level. Furthermore, traditional instruction for science including chemistry in Indonesian high school level is mainly lecture-based and students occasionally conduct chemistry laboratory activities in a very structured form of inquiry in order to verify what the textbook or instructor has indicated to be the expected result of an experiment. Limitations of learning science, in the absence of inquiry experiences, are well known. When science is presented as a body of knowledge, students are discouraged from developing their own explorations and explanations of observed phenomena (see Trumbull et al., 2005). In this study, an innovative science instruction to fit within the new 2009 chemistry curriculum and to fullfil the curriculum expectation was designed, which explored the concepts of acids and bases. The innovative science instruction, which is called designed student-centered instruction, met the requirements of the existing curriculum and was conducted under all the time and other restrictions imposed by the Indonesian system. This designed student-centered instruction was a teaching-learning sequence oriented toward contemporary approaches suggested by the chemical education research literature. It included the use of hands-on/inquiry-oriented and collaborative activities connected to students’ everyday life materials and environmental issues. According to Wise (1996) any innovative science instruction should be a mixture of teaching strategies and no one strategy is as powerful as utilizing a combined strategies approach. If students are placed in an environment in which they can actively connect the instruction to their interests and present understandings and have an opportunity to experience collaborative scientific inquiry under the guidance of an effective teacher, achievement will be accelerated. Therefore, this study examines whether a designed student-centered instruction was more effective in teaching acids and bases than traditional instruction, and whether this design was also effective when it was implemented for Japanese senior high school students.
THEORETICAL BACKGROUND
Constructivist Approach
Recent research in science education has been dominated by a constructivist perspective of learning. According to this perspective, students do not passively absorb information, but rather, meaningful learning involves the active creation and modification of knowledge structures (Carey, 1985). So, learning is considered as an individual process that involves linking new ideas and experiences with what the learner already knows through interactions with the physical and/or social environment (Liang and Gabel, 2005). Basically, it stresses the thought processes of the learner and assumes that prior knowledge, attitude, motivation, and learning style affect the learning process (Spencer, 1999). Table 1 provides a summary of the differences in emphases between traditional and constructivist learning environments.
Table 1. Elements of emphases in traditional and constructivist learning environments
Traditional Constructivist
Instructional emphasis
Teaching, knowledge reproduction, independent learning, competition.
Learning, knowledge construction, collaboration, reflection
Instructor roles
Expert, source of understanding, lecturer
Collaborator, facilitator, encourager, community builder
Student roles
Passive, listener, consumer of knowledge, note taker
Active, collaborator, constructor of knowledge, self-monitoring
Assessment
Fact retention
Authentic knowledge application, portfolio, projects, performances.
*Modified from Rovai (2004)
Inquiry Approach
Science including chemistry has been characterized as consisting of aspects of content and scientific process (see Bass, Constant & Carin, 2009). Content consists of statements about nature, including natural entities, the theories and concepts used to understand and explain these entities. Process consists of the practice of how science is done by scientist involving the interplay of experiment, prediction, hypothesis generation, and communication of results within a scientific community. Therefore, students in their schools should learn the content as well as experience the process.
A connection of scientific process and learning around the idea of ‘‘inquiry’’ is already well known, and a key component of pedagogical constructivist approaches is incorporated in the idea of ‘‘inquiry learning.’’(Wink, 2006). This means that inquiry instruction supports a constructivist approach to learning science (Bass, Constant & Carin, 2009: p.4). According to NSES (NRC, 1996), scientific inquiry describes the diverse ways in which scientists study the natural world and propose explanations based on the evidence derived from their work. Inquiry also refers to the activities of students in which they develop knowledge and understanding of scientific ideas, as well as an understanding of how scientists study the natural world. Therefore, providing students with authentic opportunities to conduct science inquiry is expected to enhance their abilities to successfully evaluate complex scientific ideas. Conversely, lack of experiences with scientific inquiry restricts the success with which students evaluate scientific knowledge claims (Trumbull et al., 2005).
Learning outcomes associated with inquiry dimensions of science include generating a hypothesis, developing a plan for gathering data, and constructing arguments based on evidence. Through the practice of inquiry, students acquire knowledge in a more meaningful way (Germann, Haskins and Auls, 1996). Students need ample opportunities to practice the science processes within a variety of investigations. Together with appropriate feedback and modeling, students should become more proficient and independent. If teachers and students make connections between the domain-specific contexts of the laboratory such as chemistry and more general contexts, then many students will be able to apply the science processes outside of the classroom (Germann & Aram, 1996).
Context-Based Approach
The notion of context-based approach comes from recent attempts to reform the design of courses in chemical education in order to address a number of inter-related problems (i.e., context here is used as the basis for curriculum design and classroom teaching) (see Driver, 2006; Schwartz, 2006). According to Pearsall (1999) context means “the circumstances that form the setting for an event, statement or idea, and the terms in which it can be fully understood” and “the parts that immediately precede or follow a word or passage and clarify its meaning” A context must provide a coherent structural meaning for something new that is set within a broader perspective. These descriptions are consistent with the function of “the use of contexts” in chemical education in that students should be able to provide meaning to the learning of chemistry and they should experience their learning as relevant to some aspects of their lives and be able to construct coherent “mental maps” of the subject. Bennett (2003 in Gilbert, 2006) has provided evidence from research into context-based curricula, such as pupils’ interest and enjoyment of their science lessons generally increase when they use context-based materials and follow context-based courses; context-based materials help pupils see and appreciate more clearly links between the science they study and their everyday lives; pupils following context-based instruction learn science concepts at least as effectively as those following more traditional instruction.
Designed Student-Centered Instruction Based on Constructivist, Inquiry and Context-based Approaches.
Designed student-centered instruction consists of a number of approaches, including a constructivist approach, a hands-on inquiry approach, a context-based approach, and concept map & interactive-direct approaches. The major approaches used for the design, however, were the constructivist, hands-on inquiry and context-based approaches. Table 2 provides a description of designed student-centered instruction involving the learning activities and and the outcomes in each phase.
Table 2. Learning activities, objectives and outcomes in each phase of a designed student-centered instruction.
Phase Learning activities Learning objectives Outcomes
I Introduction
• Reading a concept map
• Seeing a connection between the concept being learned and students’ daily lives/environment.
• Connect students’ prior knowledge and the concepts being learned
• See interrelationship between concepts and their usefulness
• Students’ logical conceptual framework.
• Meaningful understandings of the concepts.
II Hands-on Inquiry Activity
• Planning and discussing an experiment in a group
• Consulting the experiment plan to the instructor
• Conducting an experiment
and discussing data collected within the group
• generate a hypothesis
• develop a plan for collecting data
• construct an argument based on evidence
• An investigative knowledge
• An argumentation skills
III Class Discussion
• Sharing experimental data with the whole class
• Negotiate knowledge or concept
• New knowledge or concept
IV Application
• Applying new concepts and inquiry skills to a new but similar situation.
• see more clearly the link between concepts and their daily-life
• Meaningful understanding of the concepts
Phase 1. Introduction. Each lesson was initiated by presenting a concept map about acids and bases and by showing some examples of materials around students’ daily lives. A concept map is an instructional tool to present concepts and to show clearly the connections between the concepts. The concept map in this study was used as an advance organizer to help students accomplish meaningful learning and was designed in the light of what a student already knew or didn’t know about a concept (see Berg, 2006). The use of concept maps has been shown to facilitate learning (Hughes and Hay, 2001). In introducing a new subtopic on acids and bases we always began with a concept map. After presenting the concept map, we showed some examples of materials around student’s daily lives such as a lemon and soap, in teaching the lesson of characteristic of acids and bases. This activity was intended to make students aware that there was a connection between what they would learn in the classroom and in their daily lives and also to engage students’ attention and enthusiasm towards learning chemistry.
Phase 2. Hands-on Inquiry Activity. This activity was intended to give students direct experiences of engaging in the scientific process. This study used a fourth level of inquiry according to LeRoy & Lee (2008) in which in the inquiry process, questioning activity was innitiated by the teacher, and planning, implementing, concluding and reporting were carried out by the students. In the lesson of characteristic acids and bases, for example, students were invited to identify whether unknown solutions of A, B, and C were acids, bases or neither acids or bases. Students worked in their small groups cooperatively and discussed their inquiry plan written on their worksheets. They had to formulate the purposes and hypotheses of their investigation, the equipment and chemicals they would use and the steps of their investigation. Before conducting the investigation, students discussed their investigation plan with the facilitator/teacher and then they carried out their plan and discussed the results within their own group before making a report. According to Chiappetta & Koballa (2006), the dynamics of group work can stimulate and sustain inquiry in many situations better than individual work. Students will find a great deal of meaning in chemistry lesson when their knowledge is constructed during productive, small, collaborative group activities. Futhermore, the group work can enhance student problem solving activity as well as concept development (Lumpe, 1995).
Phase 3. Class Discussion. This activity was intended to encourage students to explain their possible solutions or answers with reference to their previous activity. Students had to exchange their ideas with other groups by writing their answers on the blackboard or by making presentations. The teacher, as facilitator guided students’ discussion by asking questions for justification (evidence) and clarification from students and used students’ previous experiences as the basis for explaining concepts.
Phase 4. Application. This activity was meant to encourage students to apply or extend their concepts or skills to a new but similar situation. In the lesson on characteristic of acids and bases, for example, we gave tasks to the students to investigate whether materials around their home could be considered acids or bases. They brought the materials to the classroom and used previous information/skills to ask questions, designed their experiments and found out the answer to their question. We provided guidance for any difficulties students faced when it was needed. In a lesson about the strength of acids and bases, we showed some pictures connected to acid rain and asked them to explain the causes of the environment al damage shown in the pictures. The activities in the application phase related to students’ daily lives and environment issues. Students would see that what they learned in the classrom related to their daily lives and their learning would be meaningful. It is important that students have multiple opportunities to practice using the concepts they have learnt, in order to establish the concepts in their long-term memory (Nuthall, 1999).
Designed student-centered instruction was used to teach the lessons on characteristics and strength of acids and bases, whereas interactive-direct instruction was utilized to teach the lessons on definition, neutralization and pH of acids and bases.
RESEARCH QUESTIONS
This study focuses on an examination of whether chemistry concepts, especially acids and bases, are made visible and meaningful to high school students using designed student-centered instruction. In the context of this study, the following research questions are investigated.
1. Is designed student-centered instruction based on constructivist, hands-on inquiry and context-based approaches, effective in increasing Indonesian students’ learning achievement?
2. What are the Indonesian students’ perceptions about their roles in the group and about the teaching and learning process?
3. Is designed student-centered instruction based on constructivist, hands-on inquiry and context-based approaches, effective in increasing Japanese students’ learning achievement?
This study uses the terms of students’s learning achievement and perception. Students’ learning achievement means the ability of students to answer the achievement test on acids and bases in terms of cognitive aspects. Whereas, according to Pearsall (1999) perception means “a way of regarding, understanding, or interpreting something”. In this study, students’ perception refers to how students regard, understand and interpret their roles in group functioning and their view of the teaching and learning process.
HYPOTHESIS OF THE STUDY
The following null hypothesis was tested at the 0.05 a-level.
Ho = There is no statistically significant difference in students’ achievement on the topic of acids and bases between students taught using designed student-centered instruction and those taught in the traditional teaching method.
METHODOLOGY
Design
This study used a triangulation mixed methods design, in which both quantitative and qualitative data were collected simultaneously, both datasets analyzed separately, the results compared from the analysis of both datasets, and an interpretation made as to whether the results support or contradict each other (Creswell, 2008). This study includes two steps:
1. A quasi-experiment was designed with treatment and control groups and pre-test and post-test design as shown in Table 2. This design was conducted for Indonesian senior high school.
Table 2. Quasi experiment design
Group Pre-test Treatment Post-test
Experiment (E) O1 X O2
Control (C) O1 — O2
*O1 is pretest; O2 is post-test; and X is treatment.
2. The similar designed student-centered instruction was implemented for Japanese senior high schools.
Participants
The participants in this study consisted of Indonesian and Japanese senior high school students. Two classes of grade 11 who majoring in science from a senior high school in Indonesia were chosen as the sample in this study. One class was treated as an experimental group which consisted of 36 students (13 boys, 23 girls), while another class was treated as a control group which consisted of 38 students (13 boys, 25 girls). The students had an average socioeconomic status and achievement level compared to other schools within the country. The traditional teaching-learning process utilizes a direct instruction and a textbook-based approach. Laboratory activities and demonstration are mostly conducted to confirm concepts which have been learned in the classroom and in the form of structured inquiry like “cookbooks”.
The participants from Japan were a class of grade 10 students of a Super Science High School (SSH) in Okayama prefecture, Japan. This students had a chemistry in English class where in this class the chemistry topic is basically delivered in English. The number of students was 35 students ( 22 boys and 13 girls). The students had an average socioeconomic status and achievement level compared to other schools within Japan.
Limitations
The external validity of this study was limited in that the study was conducted only in a high school both in Indonesia and Japan and there was no class for control group for Japanese case. The application of this designed student-centered instruction was restricted by the school schedule and the sub-topics: characteristics, definition, strength of acids and bases, neutralization and pH.
Instruments
There were three research instruments utilized in this study. These instruments were an achievement test, a self-evaluation questionnaire and an open-ended questionnaire which measured students’ understanding of acids and bases, students’ perception of their roles in group functioning and students’ perceptions on the teaching-learning process, respectively.
An Achievement Test of Acids and Bases (ATAB). The ATAB was an open ended test, consisting of twelve short-answer questions on acids and bases. The concepts investigated in the ATAB are presented in Table 3 and the examples of questions can be seen in Electronic Suplementary Materials (ESM) A.
Table 3. Concepts investigated in the ATAB
No Concepts Question no.
1 Characteristics of acids and bases 1, 5 & 8
2 Definition of acids and bases 6 & 10
3 Strength of Acid and Base 2, 9, 12
4 Neutralization 4 & 7
5 pH 3 & 11
A self-evaluation questionnaire. This questionnaire was adapted from Llewellyn (2002), consisted of thirteen statements using Likert-type ratings with four options (usually, often, sometimes, and rarely). The instrument was constructed to quantify students’ perceptions of their roles in their group functioning and their skills in the inquiry process. The self-evaluation questionnaire is a means to collect feedback about how students perceive their individual and group performances and it can provide a window into students’ perceptions about how well they did on the chemistry exploration. A self-evaluation also offers the students the opportunity to reflect on how they might improve their performances if they were to repeat a task for the second time (Llewellyn, 2002). The examples of questions on the self-evaluation instrument are provided in ESM B.
An open-ended questionnaire on perceptions towards the teaching-learning process. To obtain information regarding students’ perceptions towards designed student-centered instruction, an open-ended questionnaire was administered to students in the experimental group at the end of the study. The questionnaire consisted of four questions. Questions no. 1 through no. 3 were intended to gain information about students’ perceptions about the teaching learning process, whereas question no. 4 was intended to gain information on what students’ think are the best ways to teach chemistry. The questions on the questionnaire are provided in ESM C.
The three research instruments were given to three experts for content validity inspection. The questions on the instruments were modified according their comments. To examine internal consistency reliability, Cronbach’s alpha (Fraenkel & Wallen, 2006) was computed for the achievement test ( = 0.789) and for self-evaluation questionnaire ( = 0.785). These reliability values were adequate for use in the study. Inter-rater examination was conducted for the qualitative data from the open-ended questionnaire. The second rater was a graduate student in chemical education research with some previous experience in chemical education. The initial reliability of the classifications of responses, measured as a percentage of agreement, was 95%. All initial disagreements were resolved through discussion.
Treatment
a. Treatment for Indonesian Senior High School Students
The experimental group received the lessons on acids and bases in the chemistry laboratory in which students were treated using designed student-centered instruction as described earlier, whereas the control group received traditional instruction which is relatively more dependent on lecture and textbooks. The duration of the teaching-learning process was two weeks (8 x 45 minutes) in both classes. The students in the experimental group were taught by the researcher, while the students in the control group were taught by a chemistry teacher in the school. Pre-test and post-test were administered to both experimental and control group before and after the treatment. The study was conducted in February 2007.
b. Treatment for Japanese Senior High School Students.
A class of grade 10 of a Super Science High School received the lesson on acids and bases in the chemistry laboratory using designed student-centered instruction which is similar to those implemented in Indonesian senior high school. The lessons was delivered in English by the researcher. The duration of the teaching-learning process was two weeks (8 x 45 minutes). The study was conducted in November 2006.
Data collecting procedures
a. Procedures for Indonesian Senior High School
We administered three research instruments for the Indonesian senior high school students. Before the study began, all students in both control and treatment groups took the achievement test (pretest) on acids and bases and they took the same test (posttest) at the end of the treatment. The achievement test took 40-45 minutes to complete. Students in the treatment group also took the self-evaluation questionnaire and an open-ended questionnaire collected after the study had finished.
b. Procedures for Japanese Senior High School.
We administered two research instruments for the Japanese senior high school students. Before the study began, the students took the achievement test (pretest) on acids and bases and they took the same test (posttest) at the end of the treatment. The achievement test (ATAB in Japanese version) took 40-45 minutes to complete. Students took also the open-ended questionnaire (in Japanese) when the study had finished.
Data Analysis
Quantitative data consisted of pre- and post-test scores, percentages from the self-evaluation responses and the open-ended questionnaire responses about the teaching and learning process. Qualitative data consisted of students’ statements in the open-ended questionnaire. To answer the research question no. 1, we need to examine the effect of the treatment, pre- and post-test scores of the treatment and control groups were analysed statistically (i.e., calculated by SPSS software) using one-way analysis of covariance (ANCOVA) with significance level set at 0.05 with the pretest as covariate and followed by an unpaired sample t-test for mean gain score. To answer the research question no. 2, students’ self-evaluations were analyzed and presented in percentages and students’ perceptions towards the teaching and learning process were presented both in percentage and descriptive form. To answer the research question no. 3, a normalized gain score
Interpretations: "High-g" instructions as those with (
"Medium-g" instructions as those with 0.7 > (
"Low-g" instructions as those with (
Table 3. Adjusted ATAB mean scores obtained by students
Group Mean Standard Deviations N
Treatment 44.06 4.548 36
Control 36.63 4.647 38
ANCOVA procedure was used to confirm if the treatment group (T) and control group (C) scores were significantly different. The results are shown in Table 4. The adjusted mean scores in the ANCOVA are shown in Table 5.
As shown in Table 4, the p-value of the pre-test is 0.005 < 0.05 -level. This means that the pre-test makes a statistically significant contribution to the variation of achievement related to acids and bases as measured by posttest. Moreover, ANCOVA results shows F= 46.579 with p-value = 0.000 < 0.05 -level which means that Ho is rejected. Thus the designed student-centered instruction make statistically significant contribution to the achievement on acids and bases measured by posttest. Table 4. One-way ANCOVA of post-test ATAB scores with pre-test score as covariate Sum of square Df Mean square F P-value Pre-test (covariate) 157.933 1 157.933 8.216 0.005 Designed student-centered instruction (treatment) 895.364 1 895.364 46.579 0.000 Error 1364.798 71 19.223 Corrected total 2541.622 73 a. R Squared = 0.463 (Adjusted R Squared = 0.448) Table 5. Adjusted ATAB mean scores obtained by students Group Mean Std. Error 95% Confidence Interval Lower Bound Upper Bound Treatment (T) 43.850a 0.734 42.386 45.314 Control (C) 36.826a 0.714 35.401 38.251 a. Covariates appearing in the model are evaluated at the following values: Pretest = 28. 07. A further comparison was needed to check the mean gain of the students from the pre-test to the post-test for the treatment group and the control group 1 (See Table 6). Table 6. Comparison of the mean scores and mean gain obtained by students in ATAB Overall(N= 74) Treatment group (T) Control group (C) Pre-test mean 28.09 28.83 27.34 Posttest mean 40.34 44.06 36.63 Mean gain 12.3 15.2 9.29 Table 6 shows that the treatment group (T) has a higher mean gain score than the control group (C). A paired sample t-test between mean gain scores of T and C groups indicates a significant difference in mean gains, t = -4.05856, P-value < 0.05. Thus the group taught using the designed student-centered instruction has a higher mean gain score than the control group. The hypothesis that there is no statistically significant difference in chemistry achievement between students taught using designed student-centered instruction and those taught using the traditional teaching method is rejected at the 0.05 -level. Therefore, using the designed student-centered instruction based on the constructivist, inquiry-based, context-based approaches improves students’ performance in chemistry more than when the students are taught in the traditional teaching method. Students’ Self-Evaluation An analysis of quantitative data on the self-evaluation provides some information about students’ perceptions of their roles in their group functioning and their skills in the inquiry process or how well they did on chemistry exploration throughout the series of inquiry-based activities. The results of self-evaluation are presented in ESM B. Data from self-evaluation show that: • Question no. 1, 2, 3 and 8 were dealing with students’ doing experimental activities. The average percentage of students choosing the options were 81% on the option “always” and “often” and 12% on the options “sometimes” and “rare” (M= 3.23, SD= 0.14). We interpret this as meaning that most students felt very confident in dealing with experimental activity, such as: handling a solution properly; making an accurate observation; following their plan and using the equipments and chemicals appropriately; • Question no. 7 and 9 were dealing with students’ use of notebook, textbook and other resources. The average percentages of students choosing the options were 64% on the options “sometimes” and “rare” and 32% on the option “always” and “often” (M= 2.32, SD= 0.18). This means that many students do not rely much on their note/workbook to record observation and measurement and to use their resources to collect information for the experiment; • Question no. 4 to 6 and no. 10 to 13 were dealing with students interaction in the group activities. The average percentage of students choosing the options were 75% on the options “always” and “often” and 21% on options “sometimes” and “rare”. This data means that most of the students were very confident in working in their group activities and in doing presentations. In this case, students felt that they participated in group discussion productively, listened to other group members and respected their ideas, and shared in group work. Furthermore, students felt confident in presenting to share what they had learned with others. They, shared responsibility for the presentations, made good eye contact and projected their voices during presentations. Students Perceptions of the Teaching-Learning Process. An analysis of students’ responses on the open-ended questionnaire provided some information on students’ perceptions about the teaching-learning process in the treatment class. A classifications of students’ responses are presented in ESM C. • In question no. 1, students were asked to give their opinions as to whether the teaching learning process was enjoyable or not. The data show that almost all students (35 students or 97%) said that the teaching learning process was enjoyable. They gave reasons, for example, a lot of practical activities (30%); relate to daily lives (19%); easy to understand (28%); the teaching method was interesting and different from ordinary method (14%). • In question no. 2, students were asked to give their opinion as to whether their understandings about acids and bases had improved. The data show that almost all students (35 students or 97%) said that their understanding about acids and bases had improved. They gave reasons, for example, through practical activity the topic was easy to understand and to remember (39%); through the teaching method students could share ideas/thinking so that the topic was easily understood (41%); teaching method was interesting and made students more active (14%). • In question no. 3, students were asked to give their opinion about what the best way to teach chemistry was so that they could understand chemistry concepts well. The data indicate: 10 students (28%) liked this method/way; 13 students (36%) suggested more experiments and 6 students (16%) liked a step by step of teacher’s explanation. • In question no 4, students were asked to consider the most important concept on acids and bases they just experienced. The data show: 6 students (16%) indicated the strenght of acids and bases; 9 students (25%) preferred identification of daily life materials as acids, bases or neutral; 5 students (14%) prefered pH and concentration and 6 students (16%) said that all concepts were important. The Effect of Designed Student-Centered Instruction on Japanese Students’ Achievement An analysis of the normalized gain score was conducted for pre-and posttest results to roughly measure the effectiveness of designed student-centered instruction. Table 7 shows the gain score results from both Japanese and Indonesian students. Table 7. The normalized gain scores between Indonesian and Japanese students Japanese Indonesian Pre-test 22.77 28.83 Posttest 36.86 44.06 Gain score < g > 0.36 0.46
The data reveals that both Japanese and Indonesian students achieved medium gain scores
An analysis of students’ responses on the open-ended questionnaire provided some information on students’ perceptions about the teaching-learning process in the treatment class. Examples of students’ responses on the questions no 1 and 2 will be presented here.
In question no. 1, students were asked to give their opinions as to whether the teaching learning process was enjoyable or not. The data show that almost all students (34 students or 97%) said that the teaching learning process was enjoyable. They gave reasons which was connected to: communication in English (37%), experiment (20%), knowledge/experiences (23%), daily life materials (11%). The following are examples of students’ responses:
• “English was difficult but chemistry content was easy to understand”.
• “ Chemistry in English was the first time and I learnt many things”.
• “At the beginning English was difficult, but it became enjoyable”.
• “I knew pH values of various solutions in daily life. I became intererested in daily life materials”.
• “Because new knowledge I got and chemistry in english was enjoyable”.
• ”Experiments were enjoyable and BTB colour was beautiful”.
• “Almost all I have learnt but pH information was very detail”.
In question no. 2, students were asked to give their opinion as to whether their understandings about acids and bases had improved. The data show that most students (28 students or 80%) said that their understanding about acids and bases had improved and 7 students (20%) said that their understanding about acids and bases had not improved. Their reasons were varied and they mentioned such as: “new knowledge”, “experiments”, “ good lessons”. The following are examples of students responses:
• “I learnt many things eventhough in a short time”.
• “Various experiments on charachteristic of acids and bases”.
• “ I understood deeper from different view and good reviews”.
• “ I understood deeper because of new experiences”.
• “ Due to all english lesson, some parts are difficult to understand”.
• “ I didn’t understand due to difficulty of the lesson”.
DISCUSSION
This study was conducted to investigate the effectiveness of two methods of teaching acids and bases (i.e., designed student-centered instruction and traditional instruction) for senior high school students. The results of this study indicate that designed student-centered instruction (treatment) group significantly outperformed traditional (control) group in understanding key aspects and concepts involving acids and bases. This design was also effective in improving understanding when it implemented for Japanese senior high school students with a medium gain score, eventhough the Japanese students’ gain score was lower than Indonesian students’ gain score.
Possible reasons for the observed difference between the treatment and the control group might include the value associated with alternative ways of acquiring knowledge in science, particularly inquiry using hands-on/practical and context-based activities. During the implementation of this designed student-centered instruction, students learned through their own actions and reactions by being involved in hands-on/practical activities. Analyses of questionnaire responses in the present study suggested that the majority of students (about 97%) in the designed student-centered instruction were actively involved in the unit, enjoyed working with hands-on activities, and were very interested in participating in the activities. They also felt their understandings of the concepts had improved. Students reasoned that through practical activity (39% of students) or through this teaching method (41% of students), the concepts were easily understood. Futhermore, some students (14%) said that this teaching method was interesting, different with ordinary teaching method and made students more active. Some students (19%) enjoyed the teaching learning process because the activity related to their daily lives so that students might feel that the concepts studied were relevant and meaningful for them. This was supported by other students (25%) who preferred to choose “identification of daily lives materials as acid, base or neutral” as the most important concept they had learned.
In the designed student-centered group students explored new materials and phenomena that raised questions and encouraged them to seek answers. Student explorations involving planning, gathering and analyzing data allowed them to test their alternative hypotheses/prediction. By involving in hands-on activities students were helped to examine the adequacy of their prior conceptions and this forced them to argue about and test those conceptions. This led to disequilibrium when predictions based on their prior beliefs are contradicted and provided the opportunity to construct more appropriate concepts. The designed student-centered instruction allowed the students to have enough time to identify and express their pre-conceptions, examine their usefulness and apply the new concepts and ideas in a context familiar to them. As an illustration, in the lesson on characteristics of acids and bases, after students had constructed the concept of characteristic of acid, base and neutral substances, they had to inquiry and plan an investigation by themselves to examine whether some materials they collected around home could be considered acid, base or neutral. Results of this study showed that most of students (81%) felt very confident in dealing with experimental activity, such as: how to handle a solution properly; to make an accurate observation; to follow their plan and to use the equipments and chemicals appropriately. Students’ prior knowledge and their science process skills each made a significant contribution to their understanding of acid and base concepts. According to Lawson (2001), learning new concepts is not a purely abstract process. Rather, concept acquisition depends upon one’s ability to generate and test ideas or hypotheses and reject those that lead to contradictions. Thus, concept learning can be characterized as ‘constructive’, while new conceptual knowledge depends upon skill in generating and testing ideas. As one gains skill in generating and testing hypotheses, concept constructions become easier. Futhermore Ausubel (1968) claimed, students learned meaningfully by constructing new knowledge on the basis of what they already know. Thus, students existing conceptions have great influence on their further learning. Student outcomes might be improved by creating classroom environments found empirically to be conducive to learning (Fraser, 1994). The result of this present study supports this view.
In the traditional group, however, a concept or a group of related concepts was verbally introduced and explicated in the lecture and/or confirmed in the laboratory activities. Thus, students in the traditional group mainly focused on concepts related to the subject that require less conceptual restructuring.
Possible reasons for the gain score difference between the Japanese and Indonesian students might include the difficulty in communication for the lesson for Japanese students. Chemistry lesson in English was the first experience for Japanese SSH students grade 10. Students should learn English as well as the chemistry content of acids and bases. They had to understand their worksheet in English and do presentation in English. All teaching aid and materials were prepared and delivered to students in English. The students came from various background and had an average socioeconomic status and achievement level compared to other schools within Japan. Eventhough many students (37%) concerned about their English, almost all of them (97%) enjoyed the acids and bases lessons. This was a good aspect to increase students’ motivation and attitudes towards teaching and learning of chemistry. Conversely, for Indonesian students, the acids and bases lessons were delivered in their own language, Indonesian. So, Indonesian students did not have difficulty in communication.
From the results of this study, we concludes that:
1. Designed student-centered instruction based on constructivist, hands-on inquiry and context-based approaches is effective in increasing Indonesian students’ learning achievement. This study indicates that treatment group significantly outperformed the traditional group in understanding the acids and bases concepts.
2. Most of the Indonesian students (97%) in the treatment goup enjoyed working with hands-on activities. They were actively involved and very interested in the activities. They also felt their understandings of the concepts have improved. Students reasoned that through practical activity (39% of students) or this teaching method (41% of students), the concepts were easily understood. Futhermore, some students said that this teaching method was interesting, different with ordinary teaching method and made students more active. They enjoyed because the activity related to their daily lives so that the concepts studied were relevant and meaningful for them. This was supported by some students who chose the identification of daily life materials as acid, base or neutral as the most important concept they had learned. Most of students (81%) felt very confident in dealing with experimental activity.
3. Designed student-centered instruction based on constructivist, hands-on inquiry and context-based approaches is effective in increasing Japanese students’ learning achievement. Japanese students achieved a medium gain score from implementation of designed student-centered instruction. Almost all Japanese students (97%) enjoyed the lessons of acids and bases and most of them (80%) felt that their understandings of the concepts have improved. Some of them found that English as a barrier of their learning but they were getting confident with English.
IMPLICATIONS FOR TEACHING AND LEARNING CHEMISTRY
This student-centered instruction designed using the principles of constructivist, inquiry and context-based approaches may be of particular value to the prospective and inservice science/chemistry teachers, especially in Indonesia. Efforts to increase present & future science teachers’ attitudes toward using inquiry as suggested by the new 2006 curriculum are of particular importance in that they may result in effective science instruction. Although the essencee of inquiry teaching is not always easy to grasp and implementation has proven difficult (Deboer, 2006), the inquiry-based pedagogy designed in this study, underpinned by constructivist and context-based approaches designed in this study has proven its potential to enhance student learning and to motivate the students. Prospective & preservice teachers should understand the variety of ways that inquiry teaching can be used and the range of meanings it can have. This should aid educators in moving towards pedagogies that are effective and motivate students, and that deepen their intellectual engagement with scientific ideas and that give them a better sense of what science is.
For Japanese side, this designed student-centered instruction could be implemented and it might be appropriate for Super Science High School students. Since grade 10 SSH students were benefited from the teaching and learning process in this study, such as: increase students’ achievement, motivate students to engage in the classroom activities and increase their self-confident and skills in English.
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