Comparative study of using 5E learning cycle and the traditional teaching method in chemistry to improve student understanding of water concept: The case of primary school

Abstract The aim of this study was to compare the 5E learning model with traditional learning methods in terms of their effect on students’ conceptual understanding of water subtopics. The participants of the study were grade 8 students of 2021 academic year. While 27 of them were randomly assigned to the experimental group, the other 27 were assigned to the control group. The experimental groups were taught with 5E instructional model of the constructivist approach, whereas the students in the control group were taught with the traditional approach. Both qualitative and quantitative research methods were used in this study. Research questions were answered using mean and standard deviation, while the null hypotheses were tested using t-test at 0.05 significance level. The results from pre-tests showed that there was no significant difference between the control group and the experimental group. On the other hand, the post-test results showed that there was a significant difference between groups in favor of the experimental group. Also, the experimental group’s perception of motivation in classroom learning environment during the treatment was higher than that of the control group. It is essential that teachers should develop their skills for designing a constructivist-learning environment within class. With this aim, teachers should be given in-service training.


Abstract:
The aim of this study was to compare the 5E learning model with traditional learning methods in terms of their effect on students' conceptual understanding of water subtopics. The participants of the study were grade 8 students of 2021 academic year. While 27 of them were randomly assigned to the experimental group, the other 27 were assigned to the control group. The experimental groups were taught with 5E instructional model of the constructivist approach, whereas the students in the control group were taught with the traditional approach. Both qualitative and quantitative research methods were used in this study. Research questions were answered using mean and standard deviation, while the null hypotheses were tested using t-test at 0.05 significance level. The results from pre-tests showed that there was no significant difference between the control group and the experimental group. On the other hand, the post-test results Asrat Dagnew Kelkay ABOUT THE AUTHOR Asrat Dagnew Kelkay is an associate professor of Curriculum and Instruction at Bahir Dar University, College of Education and Behavioral Science. He has been serving the department for the past 17 years. His academic qualification is in pedagogical science, curriculum and instruction and education in his first, second and third degree, respectively. He has been offering courses for both post-graduate and undergraduate studies. He has published various articles (42) in reputable Scopus indexed journals. Dr. Asrat has been pursuing various positions in the college including: Coordinator for quality assurance, head department of teacher education and curriculum studies, post graduate program coordinator and also participating in various committees in the department. Furthermore, he has prepared teaching modules for the regular class at Bahir Dar University. These include Curriculum workshop, teacher as a reflective practitioner, general methods of teaching, action research, instructional design, secondary school curriculum and sociology of education.

PUBLIC INTEREST STATEMENT
This study is expected to be an in-put towards fulfilling the need for experimental and designbased studies, which should investigate the effectiveness of teaching chemistry at elementary level of water concepts. The findings will hopefully be of benefit to: primary school students, educators, education planner and curriculum designers. Inspiring upcoming science student will benefit from the study providing the 5Es Learning Model of Science instructions that lead to higher achievement in water chemistry and increased interest in chemistry. It encourages students to interact intimately with the subject matter of Chemistry through constructing their own knowledge from pre-existing ones thereby engaging them in productive high cognitive processes and thinking. In instruction based on 5E learning cycle model, students' prior knowledge should be taken into account and integrated with the new knowledge. The study might be used to provide guidance to elementary school teachers regarding a more effective way to teach chemistry topics.

Introduction
Constructivist learning theory is based on a philosophical understanding quite different from objectivist methodology, in terms of what knowledge is and what it means to know something. The objectivist view lies at the foundation of the perspective in the belief that knowledge or meaning does not exist in the external world independent of the individual; that is, it is not passively transmitted from the outside world into the mind of the individual but, rather, it is effectively constructed by the individual in the mind (Duffy & Cunningham, 1991). In designing teaching processes based on the constructivist theory of learning, one of the most useful forms used is the 5E instructional model developed by Bybee, a leading scientist in the Biological Science Curriculum Study (BSCS) (R. W. Bybee, 1997). This model is based on five different stages of learning: Engage Explore, Explain, Elaborate and Evaluate. In the process of meeting the goals defined in science education, it can be seen that the 5E teaching model is preferred by educators, due to its foundation in the constructivist theory of learning and its status as a planned methodology in science education that offers students effective learning opportunities. Research on the 5E instructional model supports the view that this methodology can result in significant gains in the process of learning science. Some of the positive behavior and skills achieved by using the 5E instructional model in science education have been expressed in terms of attaining increased success in teaching science with the model, helping students to retain better concepts in their minds, achieving the development of improved attitudes and behavior toward lessons, developing reasoning skills and superior processing skills (Brooks & Brooks, 1999).
In the 5E model, the Journal of Education and Training Studies Vol. 3, No. 6; 2015 students are able to understand and interpret the topic on his/her own, thereby rendering the learning process meaningful and permanent. Most of the research in Ethiopia and international literature on the 5E instructional model has engaged with students' academic achievement, their attitudes toward their lessons, conceptual changes and the adequacy of learning environments designed within the framework of the 5E model. In the instruction based on the 5E instructional model designed by Evans (2004), it has been reported that students actively participated in the classes while the units were studied, so taking on responsibilities. However, it was also stated that the teacher needed more time for classroom preparation in order to implement the 5E instructional model. Bilgin et al. (2013) finds that the implementation of the 5E instructional model renders students more comfortable in the learning environment and that their achievement levels increase when experiments are included in the lessons. Liu et al. (2009) found, in their research, that a student group exposed to the 5E model recorded improvements in their scientific knowledge and perceptions. At the same time, Bilgin et al. (2013) found that, at the end of an instructional period using this model, students inquired into the knowledge they had already brought into the learning environment. That is, when they were exposed to real-life situations, the students used their observations and data to offer scientific explanations and that with regard to scientific concepts, they passed through an accurate interpretation process. Ergin et al. (2008) has also made a comparison of students being exposed to the 5E model of instruction as opposed to those who have been taught by traditional methods, finding a significant positive difference in the group of students learning the material via the 5E model. In the Turkish literature, Balcı (2005) has designed an instruction based on the 5E instructional model finding, at the end of the instruction, that students registered significant learning and exhibited conceptual changes independent of content. In a parallel study by Ergin et al. (2008) materials were developed for and used in different stages of the model. In learning settings designed in keeping with the 5E model, students are more active than the teacher; it has been concluded that, in this situation, students are able to use their critical thinking, problemsolving, discussion and teamwork skills more effectively and that the social communication in which the students engage with their peers is at its highest levels. Again, other research conducted in this area has shown that students interact with their friends, using what they have learnt in similar situations (Ergin et al., 2008). It may be said that the 5E instructional model not only increases the curiosity to explore but encompasses skills and activities that satisfy students' expectations, leading them to focus on active learning and understanding. Research has shown that the 5E instructional model engages students in the activity at hand at every stage, so supporting them in making their own conceptualizations (Martins & Oyebanji, 2000).
Education involves the total efforts of the community to raise its political, social and economic standard of living (Tebabal & Kahssay, 2011). The implication of this is the development of a nation that depends largely on the level of its scientific and technological literacy. Thus, the importance of chemistry as a subject cannot be underrated especially in Ethiopia where the national income rests on irrigation and chemical industries.
Despite these arrays of teaching methods being advocated in the literature, there is no one universally accepted method. There is still uncertainty on which of these teaching methods contribute to failure or success of students' performance especially in developing countries like Ethiopia where the causes of poor performance in primary school chemistry are not well understood.
Chemistry, the branch of science that deals with the study of the composition and properties of matter, changes in matter, the laws and the principles that govern these changes, has been characterized as the most utilitarian of all the experimental sciences and is one of the subjects that is offered in the Ethiopian primary school curriculum. Since chemistry is the science that has the most direct and dramatic impact on our lives and the science that shapes the world we will live in tomorrow, the performance of students especially primary school in the subject is a major concern to Ethiopia as a developing country (Kılavuz, 2007). This uniqueness of chemistry and the central role that it stands to play in the development of any nation, when considered are, however, not evident in the performance of students.
Due to this, teachers are expected to devise ways of motivating their students to develop positive attitudes towards science and science-related disciplines and in order to facilitate the process of knowledge transmission, teachers are expected to apply appropriate teaching methods that best suit specific objectives and level exit outcomes (Kılavuz, 2007). Quite regularly, regular poor academic performance by the majority of students in chemistry is fundamentally linked to application of ineffective teaching methods by teachers to impact knowledge to learners (Adunola, 2011). Teacher variables, student's variables and environment-related variables contribute greatly to poor performance of students in chemistry. These teacher variables and students' variables are almost always intricately linked to teaching methods used to impart knowledge to students (Adunola, 2011).

Statement of the problem
Chemistry being a core subject in the study of sciences and engineering should be given special consideration. Many students find chemistry to be a hindrance in attaining their aims and objectives. For example, students wishing to read medicine cannot do so unless they perform well in chemistry. It is therefore necessary to properly guide and teach the students better in order for them to perform better in chemistry for a better attainment of their future career. Despite many years of behavioral learning theories to teaching, academic performance in chemistry is on the decline with no sign of promoting interpersonal and group interaction. Reasons for the poor performance have been attributed to the teaching method (Guloba et al., 2010). This inadequacy of the teaching methods employed is partly responsible for the inability of chemistry students to perform well in the subject during required summative assessments and ministry examinations. Lecture method, which is the commonly used teaching method, has thus proven ineffective as its adoption by most teachers is geared towards overcoming the bulky chemistry syllabus and has even led the chief WAEC Examiner Report 2015 to note that the rush over the topics could be responsible for the poor performance of students in chemistry (Balcı, 2005). This is particularly the case in primary schools within Jos North L.G.A., where the majority of students have not shown good performance in chemistry examination results in summative evaluation.
However, several studies have been conducted about teaching methods in primary schools in many parts of the world on students' performance, for example (Guloba et al., 2010). These studies indicated that the type of teaching methods used by teachers has an impact on students' performance. Thus, to reverse the problem of students' poor performance in chemistry and meet societal and industrial needs, there is need for innovative and more effective instructional techniques to be used by teachers in all chemistry classrooms.
It is against this backdrop that this study examines the comparison of 5e learning models and traditional teaching methods on Ethiopian grade eighth primary school students' understanding of water concepts in Amhara regional state, Ethiopia.

Researchquestions
(1) What is the effect of the 5e instructional models in improving students' conceptual understanding of water concepts?
(2) Is there a significant difference in the test scores of students taught with 5e instructional models and the traditional teaching methods about water concepts?
(3) How is the engagement of students when they are taught by the 5e instructional models?

Null hypothesis
The following null hypotheses are formulated for testing at p ≤ 0.05 level of significance.
Ho1: There is no significant difference between the pre-test mean scores of experimental and control groups used for the study Ho2: There is no significant difference between the mean score of Chemistry Students conceptual understanding when exposed to the 5Es Learning Cycle Model and those taught with traditional method.

General objective
The purpose of this study is to determine whether grade eighth students learn more successfully from the 5E Learning cycle or from traditional teaching methods on understanding of water concepts (water hardness, softening of water, water pollution and water purification).
Students from 8th-grade class participated in the study that covers one chemistry sub unit (water hardness, water purification, water softening and water pollution). The experimental group is learning all concepts of water through the 5E learning cycle; the control group learns all concepts through traditional teaching methods, which included lecture, taking notes and reading the textbook. After the water unit, I will switch the teaching methods for both groups. Both groups will complete the same tests and assignments. By the end of the study, I will be able to determine which strategy is successfully to teach water chemistry for eighth-grade students.

Specific objectives
• To examine the effect of using the 5e instructional models on improving students' conceptual understanding of water.
• To compare the significant difference in the test scores of 5e instructional models with the traditional teaching methods that students were taught about water concepts.
• To determine the degree of engagement in which students learn by the 5e and the traditional methods.

Theoretical framework
Constructivist ideals have been with us for a long time but have been described by other terms. Constructivism, as a theoretical framework, was set forth by psychologists Piaget and Bruner. It is an epistemology, used to explain how we humans learn. According to constructivism, knowledge cannot be transferred from the teacher to the student intact, the student constructs knowledge for him or herself based on prior experience and understanding. According to Sigel, Piaget noted that knowledge is not merely transmitted verbally but must be constructed and reconstructed by the learner and that for a child to know and construct knowledge of the world, the child must act on objects and it this action that provides knowledge of those objects.
The 5E Learning Cycle has evolved from instructional models that date back to the early 1900s. In 1901, Johann Friedrich Herbart's instructional model proposed two ideas that he believed are the basis of teaching: student interest and conceptual understanding. He believed students should be interested in what they are learning in order for instruction to be effective. Next, he thought that each new idea should be connected with an existing one. His model also included a social piece that provided students opportunities for social interaction with their peers and their teachers (R. W. Bybee et al., 2006).
In the mid-1980s, Biological Science Curriculum Study (BSCS) designed the 5E Learning Cycle. There are five phases in the 5E Learning Cycle. First, the engagement stage initiates the learning task. The activity should connect past and present learning experiences (Coe, 2001). By the end of this phase, students should be mentally engaged. Examples of engaging activities include asking questions, showing discrepant events, and defining or acting out a problem. Discrepant events are counterintuitive outcomes that create a cognitive disequilibrium that surprises observers and temporarily throws them mentally off-balance (O'brien, 2010). During the engagement phase, students should ask and respond to questions and show interest in the lesson. The teacher should generate interest and curiosity, raise questions and problems, and discover students' prior knowledge (Barufaldi, 2002). After the students are engaged, they have time to explore their ideas in the exploration phase. The activities in the explore phase are designed so that students share similar experiences and build more of their own ideas of the concepts. Students and teachers use their experiences from this phase to make meaning of concepts. Students are given time to investigate and manipulate materials throughout this stage. In the time that is given, students should think creatively, try a variety of problem-solving strategies, make predictions, listen to peers, record observations and ask questions. The teacher's responsibility is to act as a facilitator (Barufaldi, 2002).
After the students have had enough time to explore, the teacher begins the explanation phase. During this stage, the teacher discusses the engagement and exploration activities. Throughout the explanation, the concepts and ideas should become clear. The stage begins with the students explaining their findings. Then, the teacher provides direct instruction to clarify the concepts and information. While the students and the teacher are explaining, the students should listen and ask questions, discuss the experiences in the prior stages, and communicate new understandings. Teachers provide definitions to new vocabulary, use previous stages to explain concepts, encourage questions and participation, and ask students to clarify thoughts. After the students and teacher have explained their experiences, it is important to elaborate on the concepts. During the elaborate phase, the teacher provides opportunities for the students to apply their learning in different contexts. Students apply new definitions and skills, ask questions, propose solutions and develop experiments to test their theories. Teachers expect students to use new vocabulary and encourage them to apply their new skills to different situations (Barufaldi, 2002).
The final E is evaluation. The evaluation to determine each student's level of understanding can be formal or informal. At this point in the cycle, the students receive feedback on their explanations. Based on the evaluation, teachers can determine if their students met their performance indicators. During the evaluate phase, students demonstrate their level of understanding of concepts, answer open-ended questions, and assess his/her progress. Teachers ask open-ended questions and evaluate his/her students' knowledge (Barufaldi, 2002).
Traditional instruction the epistemology that is dominant in most classrooms today is influenced by objectivist philosophy; most teachers view knowledge as something outside the student for the teacher to give to the student. Knowledge is out there to be had, residing in books and independent of human beings (Finn & Ravitch, 1997). The philosophy of objectivism posits that the Universe exists independent of consciousness. The function of consciousness is not to simply create reality but to apprehend it. Objectivity is a major component of the search for truths, which underlie reality; learners are encouraged to view objects, events and phenomena with an objective mind, which is assumed to be separate from cognitive processes such as imagination, intuitions, feelings, values, and beliefs (Barufaldi, 2002). Teachers supply textbooks, and through note taking and lecture, the students "learn" the information. There is usually only one way to arrive at the "truth" or correct answer. How a student arrived at the answer is not very important, just that he or she did. Finn and Ravitch coined the term to traditionally describe teaching practices, focusing on teacher-centered instruction, which in their opinion is superior to constructivism (Finn & Ravitch, 1997).

Conceptual framework
The study was modeled by a conceptual framework, which depicted a representation of dependent and independent variables and the relationships between them as shown by arrows in Figure 1. In this conceptual framework, the teaching method and students' conceptual understanding are the two main variables. It is supposed that the dependent variable (the students' conceptual understanding about water) might be affected by the independent variables (the traditional teaching method and the 5E instructional cycle approach) and would improve after the treatment by developing appropriate or effective teaching method. In other words, if the teacher is to take an effective teaching strategy, then the students have to improve their conceptual understanding. This study claims that the implementation of 5E learning cycle models significantly improves the conceptual understanding of students than the traditional teaching method.

Constructivist teaching approach vs. traditional method
Constructivist teaching approach is different from the traditional view of learning in the sense of view of the real world. The traditional view focuses on instructional goals such as recalling facts, generalization, defining concepts and performing procedures (Almala, 2005). Therefore, this view ignores the differences in preexisting knowledge of individuals. On the other hand, it has been showed that constructivist teaching approach is effective in enhancing students understanding and achievement, teachers would spend less time on lecturing, drilling the students on basic concepts and rote learning (Andrew, 2007). Teachers can use the information of the students preexisting knowledge to create the instruction that can avoid the misunderstanding of concepts.
A study by Almala (2005) concluded that constructivism allows for greater learning success. Active participation has been shown to lead to both greater understanding and *greater interest in the subject. Caprio (1994) examined the effectiveness of the constructivist approach compared with the traditional lecture-lab method. It was concluded that students taught by constructivist methodology seemed more confident of their learning. They had significantly better exam scores. As a result of this, constructivist teaching and learning approaches lead to greater understanding of concepts.
It was concluded that students were more active in the learning process. Students had the opportunity to see and control their thinking, and they constructed correct knowledge more confidently and became more confident in their understanding of science. In addition to these, Akkus et al. (2003) examined the effectiveness of the instruction based on the constructivist approach by focusing on the in-class teacher-student and student-student interactions within small groups over traditional method. It is indicated by the results that students instructed by the constructivist approach acquired chemical equilibrium concepts better than the students instructed by traditional method. This research study also determined that students" previous knowledge and science process skills had an influence on their understanding of the concepts related to chemical equilibrium. Caprio (1994) supports a strong emphasis on identifying, building upon and modifying the existing knowledge (prior knowledge) students bring to the classroom, rather than assuming they will automatically absorb and believe what they read in the textbook and are told in the class. Research similar to that of Caprio (1994) indicates that better exam grades were obtained by students taught using constructivist methodology. Supporting this finding, Saigo (1999) concluded that "the constructivist model has been found to slightly influence students" achievement in a positive way." The constructivist model is capable of getting students more involved in learning. Becker & Maunsaiyat (2004) in their own research study on constructivism also found that students used for their study participated more in the classroom activities and gained in content knowledge when a constructivist approach was used. Gatlin (1998), in his study, found that students in the constructivist instruction showed a higher degree of academic achievement than students in the traditional instruction in all conditions. In a research study by Gatlin (1998) he found that there was no significant difference in students" scores at the posttest between students of the constructivist group and traditional group. He reported that students" scores of those who received the constructivist approach showed a slight decrease on the delayed posttests, while students taught using the traditional approach showed a greater decrease over time. Students who received the constructivist instructional approach have a higher relation over time. It can be said that students taught by traditional means, who rely on memorization to pass tests, over time often do not remember much of the information learned. Makanong (2000)  corroborated Gatlin's finding in his research study when he found that there was no significant difference in achievement between students in constructivist group and traditional group.

The concept of 5es learning cycle model approach
The learning cycle is a model for teaching in all subject areas; it provides a basis for thematic and integrated instruction and offers many opportunities to measure real learning. It is proposed to help students progress from concrete to abstract thinking about context. The learning cycle is a teaching model based on the knowledge organization process of the mind. It helps students to apply concepts and make their scientific knowledge constant. A well-known model of science teaching and learning is called "the learning cycle" or by an alternative model is called "the 5Es." Becker & Maunsaiyat (2004) wrote the first reference to this as a part of the Science Curriculum Improved Study (SCIS) in the 1960s. In the exploration phase of the learning cycle, students discover new concepts with the guidance of the teacher. The students confront their previous experiences and existing knowledge in this phase. During concept introduction, students are introduced to a new concept. In the concept application phase, student applies their new concept into new situations. Bisbee's 5E model is as follows: Probably one of the earliest and foremost supporters of the learning cycle was the SCIS program that adapted it and included it in its science curriculum. Although there are several "E" versions (e.g. 3E, 4E, 5E, and other modifications) the basic premise is that children have an experience with the phenomena in the learning of the concept/topic. When implementations of the constructivist approach are examined, some operators transformed three staggered circle model into five staggered circle model. The 5E model consists of Engage, Explore, Explain, Elaborate, and Evaluate Phases (Anderson & Krathwohl, 2001). The five phases, as explained by R. Bybee (2006), the 5Es model is based on both a conceptual change model of learning and a constructivist view of learning.

Research design
This study was a design-based research that employed quasi-experimental study method with control and experimental groups. A simple random sampling technique was used in assigning the experimental and the control group. Quasi-experiment is an empirical study used to estimate the causal impact of an intervention on its target population.
The quasi-experimental design that has been chosen for this study was the Pretest-Posttest nonequivalent group strategy. The purpose of this strategy was to use qualitative data and to assist results in explaining and assigning reasons for quantitative findings. The study involved systematically designed 5e instructional model lessons to be taught for experimental group and traditional teaching methods on water concepts for a control group of eighth-grade students and then to compare the effectiveness of each method on the students conceptual understanding about the topic.

Source of data
In this study, we employed a purposive sampling technique to select the school. The school has four eighth grade sections from which the particular section for the study was selected based on random sampling technique. However, the experimental and control groups were assigned after their pretest was analyzed. Their pretest has revealed that both groups of students had similar conceptions of the intended concepts; then, the researcher assigned the two groups randomly as an experimental and control group. Consequently, the participants of this study were 54 eighthgrade students from Dilchibo Primary School. Out of 27 students, 9 of them were males and 18 females, both of them were assigned randomly to the experimental group (EG), and the other 27 (there were 8 males and 19 females) students were assigned to be control group (CG). The researcher has 10 years of experience in teaching chemistry at primary and college level and has taught both groups.

Data collection methods and procedure
The main instruments used for data collection were chemistry achievement test (pretest and posttest), informal classroom assessment and observation.

Chemistry achievement test (CAT)
Chemistry achievement test was used to collect necessary data for the statistical analysis of research problem and to compare teaching chemistry by traditional method and 5E learning cycle model in teaching water on students' academic achievement. First, to determine a baseline of students' prior knowledge for both groups, the researcher gave pretests consisting of 20 questions from sub-topics of water concepts (water hardness, water softening, water purification and water pollution). Questions included different parts, which included, water concepts and critical thinking. At the end of the subtopics, they take the same post-test questions to determine how much they learned and retained.
This academic achievement test was used for several purposes: first of all, as a pre-test, it is applied to students in order to determine their background knowledge and readiness about water concepts (hardness, softening, pollution and purification). Moreover, as a post-test, it is used in order to determine the effect of teaching methods. Finally, as a permanence test after 1 month after post-test, it is applied in order to investigate the permanency of knowledge.

Statistical analysis of pretest and posttest results
Descriptive statistics analysis of pre and post test results for both groups Research question one: What is the effect of the 5e instructional models in improving students' conceptual understanding of water concepts?
To answer this research question, the pre-test scores of students mean, standard deviation, minimum and maximum of pre-test and post-test for both experimental and control groups of water concept test scores were presented As shown in Table 1, before intervention the pretest means and standard deviation scores of experimental groups were 4.37 and 2.02, respectively. On the other hand, the pretest mean score and standard deviation of control group were 4.44 and 1.93, respectively. The pretest scores of mean and standard deviations in both groups were relatively the same. Depending on their results, the prior knowledge or their understanding of water concepts was similar for experimental and control groups.
The results of water concept tests after the treatment of experimental group by 5e learning cycle model and control group by traditional teaching method were listed below. Post-test mean scores of the experimental groups were 11.48 and standard deviation 3.34, while the posttest means scores of the control group was 8.67 and standard deviation 2.37. Based on the results, the understanding of water concepts after treatment was gradually changed in each group. The mean and standard deviation posttest scores of experimental and control groups were varied and there was a significant difference between the two groups. The understanding of water concepts after intervention on experimental groups that were learned by 5e learning model of teaching approaches had resulted in better understanding of the control groups, which were learnt by traditional teaching methods about water concepts. This implies that the 5e learning model approach was an effective method to improve the conceptual understanding of students about water concepts than the traditional teaching methods.

Independent t-test analysis of pre-test and post-test result for both groups
Ho1: There is no significant difference between the pre-test mean scores of experimental group and control group students used for this study Not Significant at P > 0.05 Table 2, shows that the independent t-test analysis of the pre-test score for both experimental and control groups. The result of the t-test has been presented as the mean difference between two groups was 0.74, the level of significance α value is 0.05, sig. two-tailed (p-value = 0.891) and t (52) = 0.138; P > 0.05. Since the P value is greater than α value thus, we have enough evidence not to reject the homogeneity of the two groups in the pre-test, that is, the mean is approximately equal to a minimum mean difference. Therefore, this result showed that there was no significant difference between the mean score of the experimental and control groups in the pretest or before treatment.
The hypothesis also the t-calculated (0.138) is less than the t-critical (2.009), while the p-value is 0.891 (p ˃0.05). The null-hypothesis that stated that there is no significant difference between the pre-test mean scores of experimental group and control group students used for this study. This null-hypothesis was accepted.
Ho2: There is no significant difference between the mean score of Chemistry Students conceptual understanding when exposed to the 5Es Learning Cycle Model and those taught with traditional method.  Table 3, shows that the independent t-test analysis of the post-test score for both experimental and control groups. The result of the t-test is presented as, the mean difference between the two groups was 2.815, Level of significance α value = 0.05, sig. two-tailed (p-value =.001) and t (52) = 3.569; P < 0.05. Since the P value is less than the alpha value thus, we have enough evidence to reject the homogeneity of the two groups in the post-test, that is, the mean is not equal to a wide mean difference.
Therefore, this result showed that there was a significant difference between the mean score of the experimental and control groups in the post-test or after the implementation of the treatment. As a result, the experimental group students taught with 5e learning models performed better mean score than the control group students taught with traditional methods.
The hypothesis also showed that the t-calculated value of 3.569 is greater than the t-critical value of 2.009, while the p-value is 0.001 (p ˂0.05). The null-hypothesis describes there is no significant difference between the mean score of Chemistry Students conceptual understanding when exposed to the 5Es Learning Cycle Model and those taught with traditional method in dilchibo primary school. The null-hypothesis result was rejected.

Research question two:
Is there a significant difference in the test scores of students taught with 5e instructional models and the traditional teaching methods about water concepts?

Paired sample t-test for both group between pre-post test scores
As shown in Table 4, the result of the paired sample t-test indicates that there was a significant difference in the mean score of both experimental and control groups in their pre-test and posttest. In the experimental group the mean increases from pre-test (Mean = 4.37, standard deviation = 2.022) to post-test (Mean = 11.48, Standard deviation = 2.370). The control group pretestposttest mean scores and standard deviation were also obtained as (pre mean = 4.44 post mean = 8.67, pre standard deviation = 1.93 post standard deviation = 2.370). Based on the results, experimental group students taught by 5e learning models achieved better mean and standard deviation scores in the post test than their pretest. Control group students taught by traditional teaching methods also had better post-test scores than those of their pretest scores, but the change was relatively smaller than experimental groups in both mean and standard deviation results. As a result, an experimental group students taught with 5e learning models performed better understandings about water concepts than the control group students taught with traditional methods.
As shown in, Table 5 the experimental group mean difference between pre-test and post-test was 7.111 with a 95% confidence interval ranging from 6.348 to 7.111. In this group at t (26) = 0.000; P < 0.05. The control group mean difference between pre-test and post-test was 4.222 with a 95% confidence interval ranging from 3.793 to 4.652. In this group at t (26) = 0.000; P < 0.05. Therefore, this shows that there is a significant difference in pretest and post-test results in favor of the post-test. However, experimental group students recorded a higher mean score with 7.111 mean differences between pre-and post-test but control group students recorded relatively low mean score with 4.222 mean differences between pre-and post-test.

In general, the following major findings are obtained
• The analysis of the posttest scores indicates that there is a significant difference between students exposed to 5Es learning cycle model compared to those taught with the lecture method in favor of the experimental group. That is to say, the experimental group performed better than the control group in their academic achievement after undergoing the experimental treatment of 5Es learning cycle model.
• The analysis of pretest scores indicates that there is no significant difference between control and experimental group students that means the prior understanding of students before treatment is similar.
• Experimental group students, who are instructed by 5e learning cycle models, show better participation, interest, motivation and interaction than control group students who are instructed by traditional teaching methods.

Conclusion
Experimental group students exposed by 5E can eliminate their misunderstandings of water concepts when they take informal class assessment questions after treatment. This implies that 5Es learning cycle model is effective in promoting the thinking skills of science students, especially in chemistry. Based on this, 5Es learning cycle can be used as an effective instructional tool for eliminating poor performance and a fundamental step towards enhancing students' performance in science learning as it encourages headers to construct their own knowledge out of the prior knowledge. Therefore, from the results of this study, it is possible to conclude that the 5E instructional model of constructivist approach is a more effective method to improve students' conceptual understanding of water concepts (hardness of water, water softening, water pollution and water purification concepts) compared to the traditional teaching approach.

Recommendations
The following recommendations are made from the findings of this study; • A study can be conducted for different grade levels and different chemistry topics to evaluate the effectiveness of the 5E learning cycle model and traditional teaching methods. Because my study is limited on grade 8 th and water topic.
• Further studies can be carried out to compare the effectiveness of 5E learning cycle approach and traditional teaching methods in understanding science concepts in different schools. As a result, more accurate results can be obtained. My study is conducted only at Dilchibo Primary School.
• This study can be conducted with larger sample size out in order to obtain more accurate results.
• Similar studies can be conducted to investigate the effectiveness of instruction based on 5E instructional model of constructivist approach on students' understanding of concepts and learning strategies in other subject areas such as biology and physics.
• Science teachers should be adequately equipped with the skills needed to create an environment where all kinds of students can learn meaningfully individually or in groups especially in a chemistry class.
• Ethiopian universities and colleges of education as well as secondary school and primary school educational planner should be encouraged to design educational programs that will equip teachers in training with skills for the use of 5E instructional cycle models for effective teaching and learning of chemistry.
• Curriculum developers should incorporate constructivist strategies, such as the 5E learning cycle model into the chemistry curriculum as an instructional model for teaching chemistry in primary and secondary schools. Educational policymakers should take into consideration the desperate need for better policy, regulations, and laws that are geared toward the attainment of more meaningful chemistry education in Ethiopia.