DOCUMENT RESUME ED 357 966 SE 053 228 AUTHOR Thiele, Rodney B.; Treagust, David F. TITLE Analogies in Senior High School Chemistry Textbooks: A Critical Analysis. PUB DATE 92 NOTE 19p.; Paper presented at the ICASE Research Conference in Chemistry and Physics Education (Dortmund, Germany, June 10-12, 1992). PUB TYPE Information Analyses (070) EDRS PRICE MF01/PC01 Plus Postage. DESCRIPTORS *Chemistry; *Cognitive Development; Concept Formation; Constructivism (Learning); *Content Analysis; Foreign Countries; High Schools; Science Education; *Secondary School Science; *Textbook Content; *Textbook Evaluation IDENTIFIERS *Analogies; Australia ABSTRACT Analogies are considered an effective method for providing a bridge between unfamiliar concepts and knowledge that students already have. This paper reports a critical analysis of analogies found in chemistry textbooks used by Australian senior high school students and is presented in three sections. The first section of the paper presents the definition of analogy and discusses different types of analogies, their use in teaching, and potential constraints to their effective use. The second section reports a two-part study of 10 chemistry textbooks. A content analysis: indicated that 93 analogies were found in the 10 textbooks; compared the frequency of analogy use for particular targeted content areas; identified textbook authors' incorporation of instructional strategies that aim to directly assist the student to use analogies to aid understanding; and examined the type of analogies used most frequently in the textbooks. Secondly, interviews were conducted with the authors of 7 of the 10 textbooks to solicit views held by the authors concerning: analogy use; reasons for inclusion or exclusion of analogies; and changes the author would make to a later edition of a textbook. Conclusions reported in the third section indicated that: (1) authors assumed classroom teachers would effectively use the analogies, despite no evidence that teachers have pedagogical content knowledge in this area; (2) the frequency of analogy inclusion implies an unwillingness by authors to use analogies in textbook situations; and (3) the authors are unfamiliar with research guides regarding analogy presentation results. A list of 21 references and an appendix of the textbook titles are provided. (MDH) *********************************************************************** Reproductions supplied by EDRS are the best that can be made from the original document. *********************************************************************** Analogies in Senior High School Chemistry Textbooks: A Critical Analysis Rodney B. Thiele and David F. Treagust Science and Mathematics Education Centre Curtin University of Technology GPO Box U1987 Perth, Western Australia 6001 Australia "PERMISSION TO REPRODUCE THIS LI S. DEPARTMENT OF EDUCATION MATERIAL HAS BEEN GRANTED BY Mice of Educational Research and Improvement INFORMATION EDUCATIONAL RESOER (URCES ERICI CEN T Rrnp Thiplp Rndnp [}{This document has been reproduced as received from the person or organization originating 0 Minor changes have been made to improve reproduction quality docu- TO THE EDUCATIONAL RESOURCES Points of vie* or opinions stated in this official ment do not necessarily represent INFORMATION CENTER (ERIC)." OERI position or poliCy \c, ry A paper presented at the ICASE Research Conference in Chemistry and Physics Education, Dortmund, Germany, June 10-12, 1992. NI ) kr) e Analogies in Senior High School Chemistry Textbooks: A Critical Analysis Rodney B. Thiele and David F. Treagust Science and Mathematics Education Centre Curtin University of Technology Perth, Western Australia Introduction their own A currently supported view of learning is that when learners construct Recent knowledge, it is both transferable to and usable in later learning situations. this research has shown that a significant factor enabling the creation of conditions where understanding (Shulman, type of learning occurs is related to teachers' subject matter pedagogical 1986; Kennedy, 1990). Of special importance is the teachers' content-specific which knowledge (Shulman,1986). One aspect of this knowledge is the use of analogies of particular backgrounds and y communicate concepts to students can effecti Since students often lack the background to learn difficult and prerequisite .nowledge. problem unfamiliar topics encountered in chemistry, one effective way to deal with this and the knowledge is for the teacher to provide a bridge between the unfamiliar concept However, although which students have; this bridge can be provided by analogies. example, analogies have been used in chemistry teaching in a variety of contexts (see for in regular the work by Gabel and Sherwood,1980), little research has been conducted materials classroom settings about how chemistry teachers use analogies or how written there is need which involve analogies are used by teachers and students. Consequently, most for research to investigate for whom and under what conditions analogies are beneficial in chemical education. research investigation is underway in In addressing this problem, a comprehensive Centre at Curtin chemistry education at the Science and Mathematics Education used by University of Technology to identify, examine and interpret those analogies secondary level. authors of textbooks and by classroom teachers and their students at the interviews with the This research involves an examination of chemistry textbooks and students who are authors as well as observing and interviewing teachers and their classroom settings. Similar engaged in learning through the use of analogies in regular education. studies are planned and also underway in physics and biology and textbook authors To assist in the explaining of abstract chemical concepts, teachers understanding by employing teaching tools such may help students achieve conceptual material to be more easily assimilated with the as analogies. An analogy can allow new abstract terms to students' prior knowledge enabling those who do not readily think in Over the last ten years, heightened develop a better understanding of the concept. education has resulted in the interest concerning the use of analogies in science and their range of clarification of the picture of the types of analogies that are available presentation styles. intended effects since some However, the use of analogies does not always produce the from the content being students take the analogy too far and are unable to separate it under study Other students only remember the analogy and not the content learned. whilst yet others focus upon extraneous aspects of the analogy to form spurious conclusions relating to the target content. Recently, models have been developed which can be used as guide-lines for teachers and textbook authors concerning more effective analogy use and a classification system has been developed that enables researchers to systematically characterize textbook analogies. For example, both Glynn et al. (1989) and Zeitoun (1984) have presented model approaches to analogy teaching and the inclusion of analogies in textual materials. Whilst these reports are more recent than some of the textbooks under study, it is important to consider the possibility that the implications of these studies are not If this is the case, then we can reaching textbook authors and curriculum designers. expect that future editions of textbooks by these, and other, authors will continue to present analogies in what some researchers (e.g. Curtis & Reigeluth, 1984; Duit, 1991; Glynn et al., 1989; Thiele & Treagust, 1991; Webb, 1985) consider to be a less than efficient manner. This study involves a critical analysis of analogies found in chemistry textbooks used by Australian senior high school students, followed by an interpretive analysis of the views expressed by most of the authors of those books about the use of analogies in chemistry textbooks and chemistry teaching. Defining an Analogy There is a need to clearly define what an analogy is so that it is not confused with illustrations, models, and examples. For the purpose of this study, the researchers have adopted Glynn et al's. (1989) working definition: An analogy is a correspondence in some respects between concepts, principles, or formulas otherwise dissimilar. More precisely, it is a mapping between similar features of those concepts, principles, and formulas. (p. 383) 'he analogy requires the selection of a student world analog to assist in the explanation of the content specific target (or topic). The analog and target share attributes that allow Important in the presentation of a good analogy is for a relationship to be identified. This process involves a systematic comparison of the some evidence of mapping. corresponding analog and target attributes so that students are fully aware of which conclusions to draw concerning the target concept being addressed. It must be considered that both the analog and the target have many attributes that are not shared. Good mapping also gives some indication as to where this occurs so that unshared attributes are not ascribed to the target domain. Different Types of Analogies Reviews of analogy related literature (e.g. Duit, 1991) highlight a range of types of analogies which include verbal, pictorial, personal, bridging, and multiple analogies, some of which are discussed below. Further, Curtis and Reigeluth (1984), in an analysis of 52 analogies from four American chemistry textbooks, proposed several other criteria by which analogies may be further classified by their integral parts. These criteria include an analysis of the nature of the shared attributes (structural or functional), the degree of explanation concerning the analog, as well as the level of enrichment of the analogy (the It is also evident that the final extent to which the author mapped the shared attributes). 4 presentation by the classroom teacher will have a considerable influence upon the mode of operation of the analogy. Verbal and Pictorial Analogies: Those analogies which include only written text or oral presentation are called verbal analogies. As this type of analogy is often subtly embedded in the body of the text, the reader is usually left to draw the necessary comparisons and conclusions about the target from the description of the analog if one is provided. Alternatively, a pictorial analogy, which includes some pictorial representation of the analog domain, allows the textbook author or teacher to pictorially highlight the desired This method helps provide a greater degree of visualization attributes of the analog. which reduces the likelihood that the student is not sufficiently familiar with the analog. Most pictorial analogies are accompanied by some verbal explanation and hence technically should be referred to as pictorial-verbal analogies. This type of analogy is believed to assist students by relating abstract Personal Analogies: chemical concepts to student world phenomena such as people, money, food, and relationships. For example, the text may encourage the students to imagine that they are packaging sausages and rissoles into barbecue packs with each pack containing exactly two This may be shown to be analogous to a stoichiometrically sausages and one rissole. reacting system and the effect of a limiting reagent on the amount of product and excess reagent remaining in the system. Marshall (1984) suggests that this type of analogy causes better learning of concepts and that the approach is more enjoyable although she warns that personal analogies can cause students to give intuitive feelings to inanimate objects and concepts. The Advantages of Analogies in Teaching Analogies are believed to help in three major ways in that they: a) provide visualization of abstract concepts; b) help compare similarities of the students' real world with the new concepts; and c) have a motivational function. Researchers (Glynn et al., 1989; Shapiro, 1985) agree that the Visualization Process: visualization process is very important in the learning of concepts and that the analogies In an analysis of 216 analogies prompt a visualization process to aid understanding. found in science textbooks for secondary students, Curtis and Reigeluth (1984) found that chemistry textbooks contained the highest percentage of pictorial analogies (29%) compared to the total science average of only 16%. It has been proposed that analogies have been historically linked to Real World Linkage: both the explaining of science and to the processes of science. Well renowned theorists such as Maxwell, Rutherford, and Einstein are reported to have used analogical reasoning as a tool to aid problem solving, to explain hypotheses, and to communicate to audiences about early theories of atomic structure (Lewis & Slade, 1981; Shapiro, 1985). Needless to say, analogies are used more frequently when the target domain is difficult to 1991). The presentation of a concrete analog understand or is foreign to the learner (Du; in this situation facilitates understanding of the abstract concept by pointing to the similarities between objects or events in the learners' world and the phenomenon under discussion. Motivational Function: The motivational sense of analogy is due to a number of factors. As the teacher or textbook author is drawing from the students' real world experience, a In addition to this interest, students who sense of intrinsic interest is generated. S traditionally perform at lower academic levels may be more likely to achieve a greater This should result in a motivational gain for the level of conceptual understanding. students. However, it should be noted that little has been determined from empirical studies about the actual learning processes that are associated with analogy assisted instruction since most of the studies have measured only the students' recall of learned It is also not well known if analogies really do assist students to attain a level materials. of conceptual understanding or whether students only use the analogy as another algorithmic method to obtain the correct answer. The Constraints of Analogies Despite the positive outcomes of analogies stated above, the use of analogies as a teaching tool can cause incorrect or impaired learning due to several fundamental constraints Three of these constraints are analog related to the analog - target relationship. unfamiliarity, the student's cognitive development and the incorrect transfer of attributes. Analog Unfamiliarity: A significant constraint on the use of analogies in teaching is the learner's unfamiliarity with the analog selected by the textbook author or teacher. Several empirical studies on the use of analogical reasoning in chemistry instruction, for example studies by Gabel and Sherwc od (1980, 1983, 1984), indicated that a significant These results proportion of students did not understand the analog sufficiently well. emphasise the need for caution in teaching with this method and in making instructional decisions based on an evaluation of those analogies that are presented to improve student understanding of chemistry concepts. A strategy that can be employed by textbook authors to reduce the problem of analog unfamiliarity is to provide This additional 'analog explanation' concerning the analog and its relevant attributes. 'Strategy identification', will provide useful, additional information to the student. where the author engages a term such as "analogy" or "analogous", may serve as a warning to students that careful thought is required to derive the full and correct meaning from the analogical statement. Student's Cognitive Development: A second area of constraint with analogy use relates There is general agreement that to the Piagetian stages of cognitive development. analogies can assist students who primarily function at lower cognitive stages; however, the if these students lack visual imagery, analogical reasoning, or correlational reasoning, In addition, (Gabel & Sherwood, 1980). use of analogies is still believed to be limited already those students already functioning at a formal operational level may have might attained an adequate understanding of the target and the inclusion of an analogy being add unnecessary information loads that could also result in new misconceptions formed by the students. The natu-e of the analog is that it has some shared Incorrect Transfer of Attributes: attribute(s) with the target. However, it n.ay be considered that the unshared attributes attributes (Licata, 1988). No analog are as instructive to the students as are the shared simply shares all its attributes with the target as, if it did, the analogy would then become shared are often a cause of misunderstanding an 'example'. These attributes that are not for the learners if they attempt to transfer them from the analog to the target. of Textbook authors may provide further mapping in an attempt to reduce the likelihood Curtis and Reigeluth (1984) have the student incorrectly transferring analog attributes. reported that all of the 52 analogies found in four popular American chemistry textbooks included some statement concerning the nature of the shared attributes although only 10 analogies had mapped more than one attribute to create an 'extended' analogy. This encouraging lack of 'simple' analogies was not, however, characteristic of science textbooks in general. A related constraint occurs when the students attempt attribute transfer in an inappropriate manner. Rather than using the analog attributes as a guide for drawing conclusions concerning the target, the students occasionally incorporate parts, or all, of the analog structure into the target content. This is illustrated diagrammatically in Figure 1. One of the results of this incorrect transfer is that when students are questioned concerning the nature of the target content, they will answer with direct reference to the analog features. For these reasons, some instructors choose not to use analogies at all and thereby avoid these pr )blerns whilst forsaking the advantages of analogy use. ANALOG V TARGET EXISTING owl KNOWLEDGE KNOWLEDGE Desired use of analog to show the relationship between the existing and target Analog attributes are used only to draw conclusions knowledge structures. concerning the target. TARGET EXISTING ANALOG KNOWLEDGE KNOWLEDGE Undesired effect due to the incorporation of the analog into the framework relating existing knowledge to target knowledge. Incorporation of analog in new knowledge. Figure 1. When analogies are used during classroom instruction, discussion should take place to assist in the delineation of boundaries and to aid concept refinement (Licata, 1988; Webb, Indeed, Glynn et al. (1989) have produced a six step Teaching-With-Analogies 1985). model that is designed to assist teachers use analogies effectively. This model provides for a clear delineation of shared and unshared attributes by the teacher. Allowing for student involvement and discussion at the classroom level also will provide feedback to the instructor if incorrect attribute transfer has occurred. Teachers should not assume that the students are capable of effecting correct analogical transfer unassisted but, rather, they should provide explicit instruction on how to use analogies and provide The highlighting of unshared opportunity for classroom discussion on the subject. attributes may also be done by a textbook author although documented evidence of this It may be that textbook authors assume that occurrence is rare (Curtis & Reigeluth, 1984). this is not required, or that teachers will conduct this aspect with the students in class Recent research, however, indicates that teachers do not expand upon analogies time. contained in their students' textbooks when conducting their normal teaching routines (Treagust, Duit, Jos lin & Lindauer, in press). Research Focus Firstly, an examination of ten chemistry This study was conducted in two parts. textbooks used in Australian senior high school chemistry classrooms was carried out in order to determine the extent and nature of the analogies. Specifically, the study investigated the frequency of analogies found in these textbooks; compared the frequency of analogy use for particular sections of the subject matter or at different stages of the curriculum; identified textbook authors' incorporation of instructional strategies that aim to directly assist the student to use analogies to aid understanding; and examined the type of analogies used most frequently in the textbooks. Secondly, interviews were conducted with the authors of seven of the ten textbooks. Specifically, this part of the study solicited the views currently held by the textbook authors concerning analogy use; examined authors' reasons for inclusion or exclusion of analogies in instructional materials; any personal appeal for a model approach to analogy teaching; and investigated the changes the author would make to a later edition of their own textbook if they were provided with a more thorough repertoire of trialled, familiar analogies. The two parts of this study are described separately followed by conclusions drawn from the results of both parts and implications for teachers, textbook authors, and educational researchers. Analogies Used in Chemistry Textbooks Procedure Ten chemistry textbooks (see Appendix) were examined and all analogies identified were photocopied and further analysed. The textbooks used in the analysis had been identified by state syllabus organisations as those current, generally used textbooks for Australian senior secondary chemistry education. Only one of the textbooks, a British publication, was not published in Australia. A portion of text or a picture was considered to be analogical if it was aligned with the working definition stated above (Glynn et al., 1989, p. 383) and/or it was identified by the Each analogy was scrutinized concerning the following author as being analogical. features, three of which (c,d, and e) were reported for American science textbooks by (a) the content of the target concept; (b) the location of the Curtis and Reigeluth (1984): (c) whether it was verbal or pictorial; (d) evidence of further analogy in the textbook; analog explanation or strategy identification; (e) the extent of the mapping done by the author; and (f) the presence of any stated limitation or warning. Results A total of 93 analogies were identified from the ten textbooks. This resulting mean of 9.3 analogies per textbook is less than the mean of 13 reported in the American study (Curtis & Reigeluth, 1984). The number of analogies found in each book varied considerably with five books having less than six analogies whilst the other five had between 12 and 18 analogies. Each analogy was further classified independently by the two researchers with an original agreement of 93%. The remaining 7% of the classifications were agreed upon following consensus discussions. Content Analysis: The content area of the target concepts were classified into 15 categories. Table 1 indicates that a considerable proportion of the analogies (21, 22.6%) relate to "Atomic Structure" - including electronic arrangement. Other areas in which analogies were used more frequently were found to be "Energy" including collision theory - (11, 11.8%) and "Bonding" (12, 12.9%). The submicroscopic nature of these target concepts emphasizes the visualization role of analogies. Table 1. Analysis of the Frequency of Analogy Use Compared to Target Content Area. Content Area Adds & Bases 6.5 6 Analytical Methods 3.2 3 Atomic Structure 22.6 21 Biochemistry 6.5 6 Bonding 12.9 12 Chemical Equilibrium 5.4 5 Chemical Processes 1.1 1 Energy 11.8 11 Industrial Processes 1.1 1 Nature of Matter 8.6 8 Organic Chemistry 5.4 5 Periodic Table 2.2 2 Reaction Rates 3.2 3 Solutions 3.2 3 Stoichiometry 6.5 6 Analogy Location in Textbook: The page number of each analogy was used to determine a decile measure of the analogy's location within the textbook as a whole. Table 2 provides data which suggest that the analogies tend to be located more frequently in the earlier stages of the textbook( except for a number found in the 7th decile. This could indicate that conceptual targets are encountered in two phases - initially when the new work is being introduced and also, at a later phase, when more difficult concepts are being presented. Verbal and Pictorial Analogies: Forty four (47.3%) of the identified analogies had a These pictorial analogies included some diagrammatic pictorial component. Further analysis revealed that pictorial analogies are representation of the analog. frequently positioned in the margin, presumably as an anecdotal package of helpful information. However, as Table 3 illustrates, verbal analogies were rarely found in a marginalized position which indicates that authors may wish to use pictorial analogies more frequently but tend not to sacrifice the copy space. Those authors writing texts with 40 marginalized comments tend to make use of the opportunity to use this space for pictorial analogies. Table 2. Analysis of the Decile Position of the Analogies in the Textbooks as a Whole. Cum % Location 22.6 22.6 0 21 35.5 12.9 12 1 14 50.5 2 15.1 60.2 9.7 9 3 9.7 69.9 4 9 74.2 4.3 4 5 83.9 9.7 9 6 96.8 12.9 12 7 100.0 3 3.2 8 100.0 0.0 0 9 Table 3. The Frequency of Use of Marginalized and Pictorial Analogies in the Textbooks. Total Marginalized Text Body 44 49 Verba 1 5 Pictorial 44 19 25 93 Total 63 30 Further Analog Explanation or Strategy Identification: To avoid the problems of analog unfamiliarity and incorrect attribute transfer, some writers provided background This analog information concerning the relevant attributes of the target domain. explanation attempts to ensure that the student is focussing upon the appropriate The explanation may constitute a simple attributes at the time of analogical transfer. phrase of only a few words through to a paragraph thoroughly describing the analogy attributes: 56 (60.2%) of the analogies had some analog explanation which is a little lower than other reported research (Curtis & Reigeluth, 1984). Further, only 15 (16.1%) of the analogies included any statement identifying the strategy It is likely that if 'strategy identification' such as "an analogy", "analog", or "analogous". be similar to the addition of a was employed more frequently, then the effect would warning in that it will direct students towards the correct cognitive procedure and the students may be less likely to transfer analog attributes incorrectly to the target (Glynn et al., 1989). The Extent of Mapping: The extent of mapping used by the textbook authors was (a) simple - classified using Curtis and Reigeluth's criteria of 'Level of Enrichment': indicates states only "target" is like "analog" with no further explanation; (b) enriched several analogs or some statement of the shared attributes; and; (c) extended - involves