STUDENTS’ CONCEPTIONS OF THREE-DIMENSIONAL ORGANIC MOLECULAR STRUCTURES IN CHEMISTRY
ABSTRACT
The study was conducted to identify students’ levels of conceptions of three-dimensional (3- D) organic molecular structures in Chemistry, in senior secondary schools (SS III) in Agbani education zone of Enugu State. Three research questions and two null hypotheses guided the study. Descriptive survey research design was employed for the study. The population for the study was 660 students comprising of 341 males and 319 females. Multi- stage sampling techniques were used to sample 310 respondents. The instrument for data collection was a diagnostic test to identify students’ levels of conceptions (DTISLC) in 3-D organic molecular structures. To ensure the validity of the instruments, the instruments were face validated by two expert from Chemistry Education and two experts from Measurement and Evaluation, all in Department of Science Education, University of Nigeria Nsukka. The data generated from the trial testing was analyzed using Kindal coefficient of concordance, and the reliability index of 0.91 was obtained. Frequency and percentages were used to answer research questions, while Chi-square was used to test the null hypothesis at 0.05 level of significance. Findings of the study showed that many students have partial conceptions of IUPAC nomenclature of branched or substituted 3-D organic molecular structures in chemistry. Many students also have correct conceptions of numbering of unbranched parent carbon chain, drawing of structures of simple unsubstituted molecules and differentiating between isomers and transformation of formulas. The study also found that gender has no significant influence on students’ levels of conceptions in four groups (1, 2,5and 6) out the six groups under which the concepts were discussed. The influence of school location is significant only in one group
(3) out of the six groups. Based on the findings, the study recommended among others, that students should be kept abreast of time in chemical nomenclature of organic molecular structures through regular assignments, class quiz, etc to help them grasp that fundamental concept.
TABLE OF CONTENTS
Title page i
Approval page ii
Certification iii
Dedication iv
Acknowledgement v
Table of Contents vi
List of Tables vii
List of figures viii
Abstract ix
CHAPTER ONE: INTRODUCTION
Background of problem 1
Statement of the problem 8
Purpose of study 9
Significance of study 10
Scope of study 11
Research questions 12
Hypotheses 12
CHAPTER TWO: LITERATURE REVIEW
Conceptual Framework 13
Concept of Chemistry 14
Students’ Conceptions 19
Gender 27
School Location 30
Theoretical Framework 31
Social Constructivist theory of learning (Vygotsky, 1978) 31
Ausubel’s theory of meaningful learning (1968) 32
Empirical Studies 35
Three dimensional structures and conception 35
Gender and conception 38
School location and conception 40
Summary of Literature Review 41
vi
CHAPTER THREE: RESEARCH METHOD
Design of study 44
Area of study 44
Population of the study 45
Sample and sampling technique 45
Instrument for data collection 45
Validation of instrument 46
Reliability of the instrument 46
Method of data collection 47
Method of data analysis 47
CHAPTER FOUR: RESULTS
Research question 1 48
Research question 2 49
Research question 3 52
Hypothesis One 54
Hypothesis Two 55
CHAPTER FIVE: DISCUSSION, CONCLUSION AND SUMMARY
Students’ levels of conceptions 58
Influence of gender on student’s levels of conceptions 63
Influence of school location on students’ levels of conceptions 65
Conclusion 68
Implications 69
Recommendation 69
Limitation 69
Suggestion for Further studies 69
Summary 70
REFERENCES 72
APPENDICES 79
CHAPTER ONE
INTRODUCTION
Background to the Study
In Nigeria education system, science is so important that it’s teaching and learning has been greatly emphasized. Chemistry is one of the most important branches of science; which enables learners to understand what happens around them. Chemistry is a core subject for Medical Sciences, Textile Science, Agricultural Science, Synthetic industry, printing technology, Pharmacy, Chemical technology etc (Jegede, 2007). Chemistry is one of the science subjects in science curriculum that is important for any given progress in technology. It occupies a central position among all sciences (Ahiakwo, 2012). The current West African School Certificate Examination (WASCE) and National Examination Council (NECO) syllabus in chemistry contains topics in physical, inorganic, analytical and organic chemistry which is the basic focus of this study.
Organic chemistry is an essential part of everyday life and it has enormous economic importance in breweries, cosmetic industry, plastic etc. Chemistry learning requires much intellectual thought and discernment because it is replete with many abstract concepts (dissolution, particulate nature of matter, bonding and structures etc.) which are central to further learning in both chemistry and other sciences (Taber, 2002). These abstract concepts are important because further studies in chemistry concepts or theories cannot be easily understood if these underpinning concepts are not sufficiently grasped by students (Coll & reagust, 2001; Nicoll, 2001). One of the essential characteristics of concept learning in chemistry is the constant interplay between the three levels of thought (macroscopic, microscopic and symbolic levels). In organic chemistry, the symbolic level which involves formulas, structures and equations etc is a major challenge to students (Sirhan, 2007).
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Moreover, Childs and Sheehan (2009) have identified the organic components of chemistry as a problem area at secondary school level of education. Sirhan (2007) also investigated problems arising from organic chemistry and indicated that students had little conceptual understanding of some concepts such as bonding, structure etc in organic chemistry. Ratcliffe (2002) has equally found organic chemistry to be one of the main areas of difficulty for Irish pupils at second level. Katz in O’ Dwyer, Hanley and Childs (2010) opined that among students, the organic chemistry course has a bad reputation of mythic proportions. From their viewpoint, organic chemistry is a dreaded wash-out. The chief examiner’s report (2008) has recognized a tendency for candidates to avoid organic chemistry questions even though this severely restricts their choice of question on the examination and equally affect their scores.
Jimoh (2005) identified organic chemistry as one of the difficult topics in our chemistry curriculum which can contribute to poor achievement in chemistry. For instance, chief examiner’s report for WASSCE (2009& 2013), has shown that inability of students to grasp the concept of IUPAC (International Union of Pure and Applied Chemistry) system of nomenclature affects the understanding of molecular structures which will in turn affect students’ learning and achievement in organic chemistry. Presently, the IUPAC system of nomenclature is the only accepted scientific method for teaching and learning of molecular structures (3-D) in chemistry. Any other method students may have acquired in school or society which is not in line with accepted IUPAC system is regarded as students’ conceptions.
In this study, students’ conception means students’ understanding or belief of what the structures and names of organic molecules should be, which differ significantly from that which is socially agreed by scientific community (.i.e. IUPAC system) (Garnet, Garnet & Hackling 2008). Students’ conceptions are also ideas and notions held by students that are
contrary to those generally accepted by mainstream scientists (Carl, 2008). Until students’ ideas are in line with scientific ideas being expounded, learning of organic chemistry cannot be said to have taken place. This is because, for most of the concepts being taught in organic chemistry, students may already have ideas which differ from the scientific accepted rules, and that can hinder the actual conceptual change which is the aim of every science instruction (Vasniodou & Loannides, 1998). Students’ conceptions often result when new experiences are interpreted in the light of prior experiences, and new understanding is grafted unto prior understanding.
According to Wandersee, Mintzes, and Novak (1994), no matter how gifted groups of students concerned, each group will have students with varied conceptions of a given concept regardless of age, ability, background etc. Students’ conceptions are very difficult to change; only very specific teaching approaches (conceptual change strategies) have shown promise of getting students accept new explanations.
Students’ conceptions play a significant role in learning chemistry than simply producing inadequate explanations to questions. The students believe that most of the explanations are correct because these explanations make sense in terms of their understanding of the behaviour of things around them (Mulford & Robinson, 2002). Consequently, if students encounter new information that contradicts their original conceptions of a concept, it may be difficult for them to accept the new information because it seems wrong and does not fit their expectation. Under this condition, the new information may be ignored, rejected, disbelieved, and deemed irrelevant to current issues, reinterpreted in the light of students’ current theories or accepted with minor changes in the students’ previously held conceptions. Mulford and Robinson further stressed that if new information is presented in a learning situation where the students are rewarded with grades for
remembering it, the information may be memorized in order to earn the reward, but it is likely to be quickly forgotten because it contradicts the learners previously held conceptions.
However, if it is true that students must construct their own understanding and must build new understanding out of conceptions that they already possess in chemistry, then it is inescapable that students will need to draw on their previous conceptions for pieces that they can rearrange and reuse to form new conceptions (Horton, 2007). Ausubel’s work (1968) and social constructivism theory have laid the basis for understanding how meaningful learning can occur in terms of the importance of being able to link new knowledge on to the network of concepts which already exist in the learners mind. Since concepts develop as new ones are linked together and the learners do not always correctly make such links, it may lead to students’ conceptions (Taber, 2001).
Taber (2001) believes that most students’ conceptions in chemistry (organic molecular structures) do not derive from the students’ unschooled experiences of the world. This is because in chemistry as opposed to biology and physics, the frameworks available for making sense of such abstract notion as three dimensional organic molecular structures derive only from the learners understanding of prior chemistry teaching. For example, it is hard to explain why a student would come to chemistry class believing that sodium chloride lattice comprised of diatomic molecules or that all organic compounds are solids and dissolve in water. Such ideas develop from the way the topic is taught, or is a result of students working beyond their level (i.e. keen students) may read ahead and misinterpret material for which they have inadequate background knowledge (Taber, 2002).
This is why an understanding of students’ conceptions in naming, construction and application of organic molecular structures can help teachers devise effective teaching strategies that can lead to conceptual change. Any instruction that fails to acknowledge and address students’ conceptions will not foster real growth in understanding of the subject
(Horton, 2007). Thus, being able to recognize or identify and work with the students’ previous held ideas and conceptions is the key component of an effective educational strategy in learning of the molecular structures. Organic molecular structures in this study are the three dimensional molecular structures in organic chemistry. They are structures of organic compounds in which each carbon atom is bonded to four other atoms with single bond (Morrison& Boyd, 2005). The atoms that make up the molecules are arranged three- dimensionally in space with a tetrahedral geometry, hence the name 3D. For example are; alkanes, alkanols, and alkyl halides.
Knowledge of molecular structures is now regarded as fundamental to progress in organic chemistry (Horton, 2007). Molecular structures could be used to predict molecular shapes, to provide insight into a molecules’ reactivity, (i.e. show where reaction occurs), describe the intermolecular forces among molecules and to explain patterns in chemical and physical properties (Cooper, Grove, Underwood & Klymkowsky, 2010). Many students have difficulty constructing molecular structures which are not an end on themselves but a key component to understanding a wide range of organic chemical observations. Flaws and ambiguities in students’ abilities to name, draw or construct molecular structures will create problem, when they need to interpret and apply these structural representations (Cooper, Grove, Underwood & Klymkowsky, 2010). Many students also express frustration at not being able to determine what the correct attachment of atoms in space (spatial orientation that leads, to three dimensionality of the molecules) should be. They often cope with the difficulties by relying on memorized cues or remembering similar examples they have seen in class or text books rather than understanding the rules and principles involved.
According to Lythcott (1990), few students with good grade in organic chemistry questions at O level, do so by rote memorization of facts without having an in-depth knowledge. For example, many students have memorized the molecular formula of ethanol to
be C2H5OH, but are unable to explain why it is so in terms of bonding structure and cannot relate it to C2H6O, or draw the expanded or graphic structure. Cooper, Grove, Underwood and Klymkowsky (2010) found out that many students were confused about how to construct valid bonding structure of organic molecular structures. The researchers also stated that as the number of carbon atoms in the structure increased, the percentage of students constructing correct representations fell significantly. The students have little idea as to how to convert or change between molecular formula, condensed formula, expanded structural formula, skeletal structures etc (Lawrie, Appleton, Wright & Stewart, 2009). All the above issues show that students’ conceptions of organic molecular structures in chemistry can differ from what they are expected to learn. Chiu (2005) posits that students’ conceptions can arise from peer interaction, gender, media, symbolic representation, school instruction and text books.
According to Okeke (2008), gender refers to the socio-culturally constructed or created characteristics and roles which are ascribed to males and females in any society. It has to do with peculiar responsibility and roles of men and women that are created in the families, societies and cultures. Okeke (2008) characterized the male attributes as bolds, aggressive, tactful with economical use of words; while females are fearful, timid, gentle, dull, submissive and talkative. Gender characteristics though learned, have lasting and far reaching implication in teaching and learning of chemistry. Gender has been noticed as having important influence on both vocational and educational options and the ease or difficulty with which science in general and chemistry in particular is conceived by students.
Ezeudu and Obi (2013) found out that male students achieved better than females in chemistry. Eke, (2003) found that male secondary school students performed better than females in science subjects and mathematics. Okereke and Onwukwe (2011) in another study showed that male students achieved better than female students in chemistry. Oludipe (2012)
maintained that gender has no significant influence on students’ achievement in science. Inyang and Jegede (1991) also reported that gender has no influence on students’ achievement in science. These differences in achievement may be attributed to gender stereotype which encourages male and female students to show interest in subjects relevant and related to the roles expected of them in the society. These inconclusive research reports show that the issues of gender in teaching and learning of sciences (chemistry) is not yet resolved. It is imperative now to find out if there are gender differences in students’ levels of conceptions of organic molecular structures in chemistry.
However students’ conceptions in chemistry may also be influenced by the location of schools. School location refers to community in which the school is situated such as rural or urban areas, (Paris, 2002). Ezewu (2006) stated that rural or urban areas could have influence on a child’s ability to study and perform at the level expected of him or her. Ezike (2001) conceptualized urban environment as those environment which have high population density containing recreational centers, good roads, communication network, big markets and banks, social amenities, well equipped libraries and laboratories, great number of qualified teachers who prefer urban environment and among others. Ezike (2001) further identified rural environment as being characterized by low population density containing low variety, and isolated place view.
According to Boylan and Mcswan (1998), rural schools also suffer high staff turnover which leads to lack of continuity in their curriculum. Boylan and Mcswan (1998) further pointed out that rural schools are staffed by young, beginning and often inexperienced staff that regrettably, would not conform to socio-cultural ethos, and above all offered a restricted curriculum especially to secondary students. Onah (2011) and Owoeye (2002) indicated that schools in urban areas achieved more than schools in the rural areas in science subjects. Owoeye and Yara (2011) in their studies showed that schools in urban locations had better
academic achievement than rural counterparts in chemistry. Ezeudu (2003) and Bosede (2010) showed that location of school has no significant effect on students’ academic achievement. Ezeudu and Obi (2013) did not also find any significant difference in the academic achievement of urban and rural school. These contradictory findings generated to the present study to see the influence of school location on students’ conceptions of 3-D organic molecular structures in chemistry.
Since students’ conceptions, gender and school location have been thought to be important variables in meaningful learning of molecular structure and organic chemistry, it is crucial to identify the students’ conceptions, the influence of school location and gender on their conceptions of 3-D molecular structures. This study therefore will identify the students’ conceptions in 3-D organic molecular structures with respect to students’ levels of conceptions, gender, and school location.
Statement of the Problem
Teaching and learning of chemistry is important for any given progress in technology in every nation. Research findings revealed that chemistry as a subject is replete with many abstract concepts such as chemical bonding, molecular structures etc. These abstract concepts are important because, further studies in chemistry cannot be easily understood if students do not sufficiently grasp them. The 3-D organic molecular structures is one of such abstract concepts that students have problem with. Despite all efforts by teachers to arouse students’ interest in organic chemistry, students still encounter difficulties in naming, drawing structures and writing equations for organic reactions using molecular structures. Research studies reported that many students find organic chemistry difficult and as such avoid answering organic questions in examinations; though it restricts their choice of questions and affect their achievement in organic chemistry and chemistry in general. Even when students
attempt organic questions or score highly in the questions, they do so by relying on memorized cues without an in-depth knowledge of the concepts.
In Nigeria, much attention has not been focused on exploring students’ problem with organic molecular structures which often stems from students’ non-familiarity with scientifically accepted IUPAC rules of nomenclature as indicated in chief examiners’ report. For students to learn organic molecular structures meaningfully, their conceptions of the concept must be in line with IUPAC rules of naming and construction of molecular structures. Students’ inability to gain this knowledge leads them to develop their own conceptions which can hinder meaningful learning of organic chemistry. All the above issues show that students’ conceptions of organic molecular structures can differ from what they are expected to learn. This problem therefore has triggered the interest of the researcher to investigate the students’ levels of conceptions in 3-D organic molecular structures in chemistry, and also the influence of gender and school location on student’s levels of conceptions in 3-D organic molecular structures in chemistry.
Purpose of Study
The purpose of this study is to investigate the students’ conceptions in 3-D organic molecular structures in chemistry that impede meaningful learning of organic chemistry. Specifically, the study intends to:
1. identify the students’ levels of conceptions in 3-D organic molecular structures in chemistry.
2. ascertain the influence of gender on students’ levels of conceptions in 3-D organic molecular structures in chemistry
3. ascertain the influence of school location on students’ levels of conceptions in 3-D organic molecular structures in chemistry.
Significance of the Study
The significance of the study was viewed from both theoretical and practical significance: The theories of Ausubel (1968) and social constructivism (Vygostsky, 1978) would provide the theoretical basis for the study. Ausubel and constructivists’ theories attempt to integrate new knowledge to previous knowledge in the learner’s mental model so as to bring about meaningful learning. David Ausubel advanced the theory of meaningful learning which contrasted rote learning. Ausubels theory directly relates to this study because the theory recognizes the importance of scaffolding of information. New information is scaffolded on the learners previous knowledge or existing schema. The Ausubel theory also emphasis meaningful learning which brings about conceptual change and explains how concepts are arranged in the learners’ cognitive structures.
The constructivism theory of learning states that as each concept is presented, a student compares it to the internal structures that are already present. If the new information or experience fit, they are incorporated into the learner’s view of the world. Meaning is created in students’ mind when concrete, physical experience interacts with existing beliefs and understandings. When an experience contradicts prior knowledge, the learner becomes surprised, frustrated and then perhaps willing to learn. Students therefore are apt to engage in meaningful learning when they are encouraged to do so and guided in determining what things are most important to learn. When students acquire new ideas in the class, the new learning or information is often scaffold on their previous knowledge or experience for meaningful learning to occur. The findings of this study will authenticate or help to strengthen the tenets of the theories by exposing the levels of students’ conceptions in 3-D organic molecular structures in chemistry which can help teacher plan new experiences for the students.
The findings of this study will be practically significant to curriculum planners, teachers, researchers and students. The findings of this study will help curriculum planners identify where students’ break through are and alert them of their pitfalls. It will provide the curriculum designers with a bibliography of student’s conceptions in organic molecular structures that can guide their future planning of both subject matter content and pedagogical tools. In planning for teacher education programme through pre-service and in-service, the designers must put into consideration the students’ and teachers’ conceptions when instruction is being designed.
Knowledge of students’ conceptions will help teachers in designing effective questions for concept evaluation instrument and test in chemistry. The findings will provide teachers with a window into their students thinking, help them listen to the students more, and skillfully manage students’ discourse. Teachers will also be provided with broad bibliography of students’ conceptions in organic molecular structure and this can guide them in the choice of teaching strategies that will bring about conceptual change in students. The findings will be helpful to teachers in deciding where to start (take children’s framework as starting point), where to cover and how to contribute to the search for “bridging” concepts.
The findings of this work will provide researchers with reference material for future research and review of literature. Findings can also guide researchers to discover more gaps in this area to work on or study. To the students, it will help them compare their conceptions with more appropriate scientific view of the situation. This will also help the students refrain from wrong or incorrect conceptions in organic molecular structures and organic chemistry. Scope of the Study
This study was carried out in Agbani Education of Enugu state. Agbani was used because extensive literature search revealed that no such study has been carried out on Agbani Education zone. The choice for senior secondary three (SS3) students was because
the content scope, three dimensional organic molecular structures in chemistry is covered in the first term of SS 3, (even though it is in SS2 Syllabus for third term).
Research Questions
The following research questions guided the conduct of this study.
1. What are the students’ levels of conceptions in 3-D organic molecular structures in chemistry?
2. What is the influence of gender on students’ levels of conceptions in 3-D organic molecular structures in chemistry?
3. What is the influence of school location on students’ levels of conceptions in 3-D organic molecular structures in chemistry?
Hypotheses
The following null hypotheses were formulated to guide the study and were tested at
≤0.05 level of significance.
HO1: Students’ levels of conceptions in 3-D organic molecular structures in Chemistry are significantly independent of gender.
HO2: Students’ levels of conceptions in 3-D organic molecular structures in Chemistry are significantly independent of school location.
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