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EXAMINATION OF CHEMICAL REPRESENTATIONS IN TURKISH HIGH SCHOOL CHEMISTRY TEXTBOOKS

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The aim of this research was to examine the chemical representations that are present in Turkish high school chemistry textbooks. Content analysis was the method of analysis. Four chemistry textbooks, which were commonly used in Turkey, for each
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  472 ISSN 1648-3898  /Print/ ISSN 2538-7138  /Online/ EXAMINATION OF CHEMICAL REPRESENTATIONS IN TURKISH HIGH SCHOOL CHEMISTRY TEXTBOOKS Betül Demirdöğen Introduction In many high school chemistry courses, chemistry textbooks often lead teachers when they decide what chemical concepts they teach and the order of teaching these concepts (Justi & Gilbert, 2002; Drechsler & Schmidt, 2005). Relying on textbooks’ influence on teaching, textbooks are written assuming that most students (Chiang-Soong & Yager, 1993) and teachers can com-prehend them. On the contrary, researchers have shown that use of vague language in textbooks can cause student misconceptions in chemistry (e.g., for electrochemistry see Sanger & Greenbowe, 1999; for chemical equilibrium see Pedrosa & Dias, 2000; for chemical bonding see Bergqvist, Drechsler, De Jong, & Rundgren, 2013). In addition to language used, how the information is presented is of crucial importance in students’ learning. When information is presented with text only, students have difficulties in remembering (Mayer, 2002) and comprehending the material (Carney & Levin, 2002).Chemistry as a discipline of science is both abstract and multi-rep-resentational (i.e., macroscopic, submicroscopic, and symbolic) in nature (Johnstone, 2000a, 2000b; Talanquer, 2011; Taber, 2013). However, multi-representational nature of chemistry compensates the limitations of its ab-stract nature. Research evidences have clearly indicated that using multiple representations when presenting information increases conceptual under-standing (Ainsworth, 2006), comprehension, and remembering (Carney & Levin, 2002). Representations also have become ‘‘…one of the most pervasive and visible elements of the modern-day science textbook’’ (Lee, 2010, p. 1099) and chemistry textbooks (Gkitzia, Salta, & Tzougraki, 2011). More importantly, well-designed textbooks in terms of visuals are beneficial for students to understand the difficult concepts as well as to avoid misconceptions (Khine, 2013). However, representations have potential to create confusion (Stern & Roseman, 2004) and might limit students’ learning when excessively used (Woodward, 1993). Therefore, representations should be used in caution. Bearing these issues in mind, the aim of this research was to investigate the types and characteristics of representations (i.e., interpretation of surface features, relation to the text, the properties of captions, and degree of cor-relation between representations) in high school chemistry textbooks (i.e., from 9 th  to 12 th ) in Turkey. Abstract. The aim of this research was to examine the chemical representations that are present in Turkish high school chemistry textbooks. Content analysis was the meth-od of analysis. Four chemistry textbooks, which were commonly used in Turkey, for each grade (i.e., from 9th to 12th), were selected. When evaluating the representa-tions, a rubric including five main criteria was used: (1) type of representation, (2) interpretation of representations’ surface features, (3) representations’ relatedness to text, (4) properties of representations’ caption, and (5) degree of correlation be-tween subordinates comprising a multiple representation. The results of the research revealed that the chemical representations used in the textbooks are mainly macro-scopic, symbolic, and hybrid. Majority of the representations had explicit surface features and appropriate captions. Moreo-ver, they were completely related to the text. Most of the multiple representations had sufficient links between their subordinates. Recommendations for textbook writers and future research are provided. Keywords: chemistry textbooks, chemi-cal representations, generic qualitative research, content analysis. Betül Demirdöğen Bülent Ecevit University, Turkey   473 Journal of Baltic Science Education, Vol. 16, No. 4, 2017 ISSN 1648–3898  /Print/ ISSN 2538–7138  /Online/ Theoretical Framework  Representations in Chemistry  Chemistry is abstract in nature (Taber, 2013) and “understanding chemistry relies on making sense of the invisible and the untouchable” (Kozma & Russell, 1997, p. 949). By the use of representations, “…chemists are able to visualize, discuss, and understand the molecules and chemical processes that account for the more perceivable reagents and phenomena they observe…” (Kozma & Russel, 2005, p. 130). Although termed differently, macroscopic, submicroscopic, and symbolic representations have been pointed out as major levels in chemistry (Johnstone, 1993, 2000a, 2000b; Gabel, 1999; Gilbert & Treagust, 2009; Justi & Gilbert, 2003; Liu & Taber, 2016; Taber, 2013; Talanquer, 2011). Johnstone (2000a) explicitly argued that these three forms of representation could be thought as corners of a triangle. He elaborated his argument by advocating that any form is not superior to another rather each comple-ments the other forms. Even though it might seem that chemists and chemistry educators agreed upon the levels to represent chemical knowledge, all components have been subject to different interpretations (Talanquer, 2011). Macroscopic level is the level of chemistry, which can be observed and studied (Gabel, 1999). It is also de-fined as the form of subject, which is tangible: what can be seen, touched, and smelt (Johnstone, 2000b). That is, macroscopic level is accessible to human sense and chemistry is experiential at this level. Gilbert and Treagust’s (2009) definition also points out “experience” and “sense” properties for macroscopic representations. For example, the disappearance of solid sodium chloride in water is an example of macroscopic level for dissolving (Tan, Goh, Chia, & Treagust, 2009). Some differentiated macroscopic level from other levels by defining macroscopic as real and visible in terms of perception (Davidowitz & Chittleborough, 2009). They defined submicroscopic as real but too small to be seen with the naked eye. While Davidowitz and Chittleborough (2009) described macroscopic and submicroscopic as real, they defined symbolic as representation instead of real. In terms of perception, submicro-scopic and symbolic levels are perceived via mental images and models. Different than those, others described macroscopic representations as the observable bulk properties of matter such as heat energy, pH and colour changes, and the formation of gases and precipitates (Treagust & Chandrasegaran, 2009). There has been a definition for macroscopic representations combining the aforementioned descriptions (i.e., observable and bulk properties). They advocated that macroscopic level includes both the actual phenomena and the concepts used to describe them (Dori & Hameiri, 2003; Hinton & Nakhleh, 1999). Submicroscopic is defined as the level of representation where the behaviour of substances is interpreted in terms of the unseen and molecular (Johnstone, 2000a, 2000b). For example, using models of sodium ions, chloride ions, and water molecules to represent how water molecules hydrate these ions refers to submicroscopic level of dissolving. Atoms, molecules, ions, and structures are given as examples although structures are not explicitly defined. Differently, Treagust and Chandrasegaran (2009) emphasized the explanatory nature of submicroscopic representations at particulate level where matter is described as being composed of atoms, molecules, and ions. Taber (2013) also highlighted this by advocating that learners can give meaning to macroscopic concepts through submicroscopic theoretical models. Gilbert and Treagust (2009) stressed that submicroscopic representations seek to support a qualitative explanation for the phenomena experienced with senses, which refers to macroscopic (Gilbert & Treagust, 2009). Although Bucat and Mocerino (2009) agreed with others on what submicroscopic repre-sentations include (e.g., atoms, ions, and molecules), they focused on its imaginative nature similar to Taber (2013) who used the term “submicroscopic theoretical entities”. On the contrary, Davidowitz and Chittleborough (2009) defined submicroscopic as real, similar to macroscopic level, but too small to be seen. Also, Wu and Shah (2004) advocated that submicroscopic representations portray the structure and movement of the real particles of matter (e.g., atoms, molecules, ions, and electrons), which are too tiny to be observed. Examples of models representing particles at submicroscopic level are given as ball and stick-, the space filling- and the stick-structures (Gkitzia et al., 2011). However, stick structures especially the ones representing molecular geometry have also symbolic representations in nature, which will be explained in the next paragraph. Johnstone (1993, 2000a, 2000b) gave examples of symbolic representations as symbols, formula, equations, molarity stoichiometry, mathematical manipulation, and graphs. Gilbert (2005) elaborated mathematical expres-sions as mathematical equations such as the universal gas law and the reaction rate laws. Gilbert and Tragust (2009) defined symbolic level as seeking to support a quantitative explanation of macroscopic phenomena. Gabel (1999) gave only chemical symbols, chemical formulas, and chemical equations as examples of symbolic level rep-resentations without mentioning mathematical ones. Some scholars have also examined symbolic system in two EXAMINATION OF CHEMICAL REPRESENTATIONS IN TURKISH HIGH SCHOOL CHEMISTRY TEXTBOOKS (P. 472-499)  474 Journal of Baltic Science Education, Vol. 16, No. 4, 2017 ISSN 1648–3898  /Print/ ISSN 2538–7138  /Online/ levels, which are chemical and algebraic (Nakhleh & Krajcik, 1994). At chemical level, substances and processes are symbolized using chemical language and drawings. Relationships between the properties of matter are expressed using formulas and graphs in algebraic level. Different than the aforementioned scholars giving popular examples of symbolic representations (e.g., element symbols [Fe] and chemical formulas [H 2 O]), Taber (2009) gave specific examples of symbolic representations in chemistry (e.g., reaction mechanisms, Lewis structures, the letters used for atomic number (A), and constants such as K  sp ). Although signs are used to symbolize chemical substances and processes in some occasions, the signs have both symbolic and iconic nature (Hoffmann & Laszlo, 1991). For instance, structural formulas are utilized to represent molecular geometry. These formulas include the types of atoms and bonds represented as symbols. However, the drawing of structural formulas gives an iconic impression as it purposes to portray the three-dimensional structure of the molecule. Consequently, Talanquer (2011) defined these kinds of representations as hybrid since they have both semi-symbolic and semi-iconic nature. Literature Review Studies about High School Chemistry Textbooks in Turkey  Research studies conducted about high school chemistry textbooks in Turkey could be examined under two headings: (1) teachers’ use of textbooks and (2) content analysis of textbooks with respect to several aspects. Researchers in the first category mostly used scales and interviews to examine how chemistry teachers use textbooks (Akkuş, Üner, & Kazak, 2014; Aydın, 2010; Eroğlu, Akarsu, & Bektaş, 2015; Nakiboğlu, 2009). Major findings of these studies revealed that chemistry teachers utilize textbooks when they plan their instruction and choose experiments and activities. However, experienced teachers prefer to use textbooks less because of the state-wide examinations for university entrance (Nakiboğlu, 2009). In terms of their opinion, chemistry teachers find the number and quality of representations not satisfactory (Akkuş et al., 2014; Eroğlu et al., 2015). Nevertheless, chemistry teachers expressed that they use visuals and representations in chemistry textbooks during instruction (Eroğlu et al., 2015). Scientific process skills (Koray, Bağçe-Bahadır, & Geçgin, 2006; Şen & Nakiboğlu, 2014), nature of science (NOS) (Aydın & Tortumlu, 2015), inscriptions in chemical reactions (Aydın, Sinha, izci, & Volkmann, 2014), nature of questions in gas laws (Nakiboğlu & Yıldırır, 2011), and semantic mistakes in the amount of substance (Pekdağ & Azizoğlu, 2013) were the aspects that have been taken into consideration during content analysis of chemistry textbooks. In terms of scientific process skills, activities and experiments in chemistry textbooks engage students in basic skills such as observation and measurement (Koray et al., 2006; Şen & Nakiboğlu, 2014). A recent research, which investigated the inclusion of NOS in chemistry textbooks, indicated that the number of NOS aspects men-tioned decreased from ninth to twelfth grade (Aydın & Tortumlu, 2015). Chemistry textbooks mostly focused on the tentativeness, the empirical-based, and the difference between observation and inference. When focusing on these aspects, chemistry textbooks employed the implicit approach to teach NOS. Another research investi-gating high school chemistry textbook questions in gas laws chapter revealed that most of the questions were algorithmic (63%) and there were lower number of conceptual questions (33%) than algorithmic (Nakiboğlu & Yıldırır, 2011). Conceptual questions did not include representations in submicroscopic level, whereas laboratory and demonstration questions were more prevalent in textbooks. There have been only two studies considering representations in high school chemistry textbooks in the topic of chemical reactions (Aydın et al., 2014) and amount of substance (Pekdağ & Azizoğlu, 2013). In the amount of substance, researchers found that chemistry textbooks included concepts that are missed at some levels of chemistry and used representations mistakenly. In the chemical reactions (Aydın et al., 2014), chemistry textbooks included symbolic representations the most (47%). Percentages for macroscopic (35%) and multiple representations were lower (12%) than symbolic. Although there have been attempts to investigate representations in chemistry textbooks, they are limited to certain topics. With these considerations, the importance of this research lies in the scope since it examines representations utilized in commonly used high school chemistry textbooks in all grade levels (i.e., from ninth to twelfth). Studies about Representations in Chemistry Textbooks This literature review focuses on the ones investigating representations in chemistry textbooks either in high school or college level. When the studies in the literature from this perspective were reviewed, three categories EXAMINATION OF CHEMICAL REPRESENTATIONS IN TURKISH HIGH SCHOOL CHEMISTRY TEXTBOOKS (P. 472-499)  475 Journal of Baltic Science Education, Vol. 16, No. 4, 2017 ISSN 1648–3898  /Print/ ISSN 2538–7138  /Online/ emerged under which these studies could be grouped: (1) representations used in chemistry textbooks, (2) repre-sentations used in some chemistry topics, and (3) representations used in questions.Studies in the first category focused on analysing representations either in high school (Chiappetta, Sethna, & Fillman, 1991; Gkitzia et al., 2011; Harrison, 2001; Shehab & BouJaoude, 2016) or in college chemistry textbooks (Kumi, Olimpo, Bartlett, & Dixon, 2013; Nyachwaya & Gillaspie, 2016; Nyachwaya & Wood, 2014). Chiappetta et al. (2011) were interested in number of pictures/diagrams in seven high school chemistry textbooks. Analysis results showed that average number of pictures/diagrams per chapter ranged between 10 and 25. Harrison (2001) investigated models used in Australian high school chemistry textbooks and found that iconic and symbolic models were used mostly. Two of the studies in high school chemistry category were interested in the same features of representa-tions (e.g., type of representation and representations’ relation to the text) and used same rubric including criteria for evaluation (Gkitzia et al., 2011; Shehab & BouJaoude, 2016). Gkitzia el al. (2011) analysed tenth grade Greek chemistry textbooks and found that macroscopic, submicroscopic, symbolic, and multiple representations were frequently used. In the research conducted by Shehab and BouJaoude (2016) with the tenth, the eleventh, and the twelfth grade Lebanese high school chemistry textbooks, it was revealed that Lebanese chemistry textbooks were focused on macroscopic, submicroscopic, and symbolic levels. In terms of other features analysed, both studies found similar results. Nearly two thirds of the representations were problematic since interpretation of surface features were left to the readers and one third of them had explicitly mentioned surface features. In terms of relation to the text, majority of the representations were completely related to the text. Also, most of the representations were appropriately captioned. With respect to a degree of correlation, more than half of the multiple representations did not indicate the equivalence between subordinate representations. Nyachwaya and Wood (2014) also evaluated representations in physical chemistry textbooks in college level by utilizing the same rubric developed by Gkitzia et al. (2011). Symbolic representations were used the most and it was followed by submicroscopic representations in physical chemistry textbooks. Moreover, the use of macroscopic representations were the least while mixed and hybrid representations did not exist. Vast majority of all representations had explicit surface features and were completely related to the text. Captions of all representations were appropriate for students to comprehend. In a recent research, Nyachwaya and Gillaspie (2016) examined representations in general chemistry textbooks with regard to number of representation, physical integration to the text, figure indexing, extended captions, labelling, representation function, and conceptual integration. Majority of the representations were representational, which presents the information in a new way. Also, 80% of representations in all textbooks were directly integrated and had captions. In terms of indexing, high proportion of representations were either indexed on a different page or not indexed at all. Another research in college level used a self-designed rubric to evaluate whether Newman (NPs) and Fischer Projections (FPs) are accurately introduced, constructed, and represented in seven frequently used organic chemistry textbooks (Kumi et al., 2013). Findings indicated introduction of both NPs and FPs were average. Construction of diagrams for NPs was better than it was for FPs. Success of representation of NPs throughout the text was mediocre while FPs were more successively represented. Researchers investigating representations in some chemistry topics mostly focused on whether representa-tions cause misconception (Bergqvist et al., 2013; Pedrosa & Dias, 2000; Sanger & Greenbowe, 1999). They were interested in type of representations in the topic less (Aydın et al., 2014; Pekdağ & Azizoğlu, 2013). Sanger and Greenbowe (1999) analysed the language and representations used in electrochemistry and oxidation-reduction chapters in college chemistry textbooks. Their findings revealed that macroscopic and symbolic representations might lead students to have misconceptions in electrochemistry. For instance, macroscopic drawing of cells and cell notation depicted by symbols imply that the anode and cathode depend on the physical placement of the half-cells. Another research focusing on chemical equilibrium advocated that high school and university chemistry textbooks’ approaches to chemical equilibrium have potential to prevent students to reach conceptual understand-ing since they reduce it to a world of symbols and equations (Pedrosa & Dias, 2000). Similarly, representations of chemical bonding models might cause students to have alternative conceptions and difficulties in understanding chemical bonding (Bergqvist et al., 2013). For instance, for ionic and covalent bonding, upper secondary school chemistry textbooks use representations showing interactions between discrete atoms while the reactants actually are composed of molecules or lattice structure.Studies in the third category were either interested in the use of representations in questions of a particular chemistry topic (Gillette & Sanger, 2014; Nakiboğlu & Yıldırır, 2011) or end of the chapter questions in all topics (Davila & Talanquer, 2010). Gillette and Sanger (2014) examined the distribution of representations used in ques-tions in gas law chapters of four high school and four college chemistry textbooks. They found that quantitative EXAMINATION OF CHEMICAL REPRESENTATIONS IN TURKISH HIGH SCHOOL CHEMISTRY TEXTBOOKS (P. 472-499)  476 Journal of Baltic Science Education, Vol. 16, No. 4, 2017 ISSN 1648–3898  /Print/ ISSN 2538–7138  /Online/ questions (N=1573) only used symbolic representations, whereas distribution of qualitative questions (N=740) in these textbooks was not significantly different based on representation types used in these questions. The percentage for the use of macroscopic representation was 37, whereas it was 33 and 30 for submicroscopic and symbolic representations respectively. Different than this research, Davila and Talanquer (2010) investigated types of questions at the end of chapter in three most used general chemistry textbooks in America. A total of 19.844 questions were analysed. Questions that require students to translate between representations or to represent and interpret information in graphical or symbolic form were few (i.e., percentages of these kind of questions ranged between .4 and 1.3). The Present Research “In discussing chemical education, the analysis of textbooks is of pivotal importance because they are the most widely and frequently used teaching aid at all educational levels” (Justi & Gilbert, 2003, p. 57). Teachers utilize textbooks as a principal reference when they think about the content and choose activities (Sánchez & Valcárcel, 1999). Moreover, textbooks may act as an alternative source of information when the teacher is unavailable (Har-rison, 2001) and students perceive textbooks as a very important part of their science education (Tulip & Cook, 1993). Hence, it is important to analyze textbooks to see the degree to which they can act as an alternative source.Based on the available data suggesting that textbooks are important for both teachers and students, authors write textbooks assuming that most students at a given grade level can comprehend them (Chiang-Soon & Yager, 1993). Even though textbooks including various types of representations are an important source for both learners (Devetak & Vogrinc, 2013) and teachers (Carvalho & Clement, 2007), the reading of these representations is not at all trivial for students (Stylianidou, 2002). Moreover, students may have misconceptions if they are left with the task of interpreting representations (Chittleborough & Treagust, 2008). Consistently, it is suggested that teachers need to put effort explaining the meaning of the representations to students (Stylianidou, 2002) since the mean-ing of a representation is not rooted in the representation itself instead is ascribed to the use of representation in practice (Kozma & Russel, 2005). For increasing the contribution of textbooks to the use of representation in practice, research suggested that linked referential connections should be made visible and information should be made explicit for decreasing students’ cognitive load (Wu & Shah, 2004). With these considerations, this research attempted to analyze the quality of captions, relation to the text, interpretation of surface features, and degree of correlation between subordinate representations to see the degree to which they ease students’ cognitive load. Finally, there have been some efforts in analyzing representations in high school chemistry textbooks with respect to some chemistry topics (e.g., chemical reactions, Aydın et al., 2014; amount of substance Pekdağ & Azizoğlu, 2013) and questions in a particular topic (i.e., gas laws, Nakiboğlu & Yıldırır, 2011) in Turkey. This research fulfills the lack of studies investigating representations used in Turkish high school chemistry textbooks. Moreover, this research focuses on the analysis of four chemistry textbooks (i.e., one chemistry textbook for each grade; from 9th to 12th) assigned by the National Ministry of Education (NME) as the primary textbook in all high schools. In other words, millions of students use these four textbooks as the primary source of nearly all information about chemistry. Also, analyzed chemistry textbooks include all chemistry topics that students are expected to learn during their high school education. Therefore, this research provides information about how Turkish chemistry textbooks including chapters about all topics contribute to Turkish students’ learning through the use of representations. By doing so, it tried to respond Han and Roth’s call (2006) that was “because of possible contextual factors, more research is therefore required focusing on science textbook inscriptions in different cultures and subject matters” (p. 176). There are possible limitations inherent in this research. First, this research was interested in representations present in four Turkish chemistry textbooks (i.e., one textbook from each grade), used throughout 2015-2016 school semester. However, chemistry textbooks are distributed to schools by NME and utilized across the Turkey. That is, millions of students utilize these four textbooks as the main source of almost all information about chemistry. Hence, the conclusions drawn from this research are beneficial to all students and chemistry teachers. Nevertheless, it would be valuable to analyze chemistry textbooks of other Turkish textbook publishers to reach conclusions that have a high generalizability degree. One can think this research is a first attempt for this kind of research. Second, representations were analyzed from chemical education researchers’ perspective on representations. Both the way teachers used and the way students see these representations are important factors influencing pedagogical contribution of these representations to chemistry teaching. As a next step, investigating students’ and teachers’ perspective would be worthwhile to provide a bigger picture. EXAMINATION OF CHEMICAL REPRESENTATIONS IN TURKISH HIGH SCHOOL CHEMISTRY TEXTBOOKS (P. 472-499)
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