Chemistry Everyday for Everyone
Turkish Secondary Students’ Conceptions of Introductory Chemistry Concepts Alipasa Ayas and Ayhan Demirbas Department of Science Education, Faculty of Education, Karadeniz Technical University, Sogutlu-Trabzon-Turkey Turkey, with a population of 63 million, is a bridge between Europe and Asia. The country was established in 1923, after the Ottoman Empire collapsed at the end of the first world war. The schooling consists of three main components: basic education (primary and middle schools, age 6–14; 8 years), which is compulsory; secondary education (lycées or senior high schools, age 14–17, 3 years); and higher education (colleges and universities). The Turkish Educational System was centralized by the Act of “Law of Unification of Instruction” in 1924. All schools throughout the country must use the same curricula, which are developed and implemented by the National Ministry of Education (1). The elementary teaching of chemistry begins with a brief introduction of physical and chemical changes (as a part of science) at the age of 10–11. Then, the introductory concepts such as atomic structure and chemical reactions are taught at age 13–14. The formal chemistry lessons start with secondary education at age 14–15. Chemistry had been regarded as a difficult subject for young students by chemistry teachers, researchers and educators (2). The reasons for this vary from the abstract nature of many chemical concepts to the difficulty of the language of chemistry. All these cause young students to develop misconceptions about a number of scientific concepts—for example, chemical change (3), particles (4), and chemical equilibrium (5). These conceptions become prior knowledge, which has serious effects for subsequent learning (6, 7). Therefore, it is important to find out students’ earlier conception in order to plan the future activities. This study aims at investigating students’ conceptions of introductory concepts (namely, element, compound, mixture, and physical and chemical changes) as a result of instruction based on the currently used chemistry textbooks in Turkish secondary schools (Lycées, ages 14–17). Literature Review Over the past two decades or so, science educators have become increasingly aware of the importance of students’ preconceptions of science concepts in order to improve science teaching. Among physical sciences, chemistry is the one for which the least research concerning students’ conceptions of underlying concepts has been undertaken. However, there has been a growing interest in it in recent years. Research has been done in areas such as particles (8, 9, 10, 11), chemical equilibrium (5, 12, 13), acids and bases (14, 15), combustion (16), and stoichiometry and chemical reactions (1, 17, 18). One area in which only a few studies have been undertaken in chemistry is how students conceptualize underlying chemistry concepts: element, compound, mixture, and physical and chemical changes (19, 20). Donnelly and Welford (16) used the Assessment of Performance Unit (APU, which is based in the U.K.) test results to find out the students’ ability to apply chemistry concepts to new situations. They specifically focused on com-
518
bustion in chemistry. They found that only a small proportion of students were able to apply their understanding or the concepts to new situations. Briggs and Holding (19) also analyzed some of the APU test questions related to element, compound, mixture, and chemical change concepts. They interviewed a group of students for a deeper investigation, as well. They found that a majority of the students had not learned the concepts well. They particularly indicated that only 25% of their sample were able to use acceptable ideas about the concepts. Ben-Zvi et al. (2) studied students’ understanding of chemical reactions in a two-part research study. The researchers found that even at the end of secondary level, students still had difficulties with some basic aspects in understanding a chemical reaction. Abraham et al. (3) found similar results for the chemical change concept with eighth grade students (14 years old). They indicated that about 86% of the students sampled showed no understanding or had developed various misconceptions. Hesse and Anderson (21) also studied the chemical change concept. They asked students to explain three oxidation–reduction reactions. The analysis showed that the students had difficulties on the following aspects: (i) chemical knowledge; (ii) conversation reasoning; and (iii) explanatory ideas. It was, as a result, argued that the topic is much more complex than teachers and textbook writers currently acknowledge. Studies concentrated on students’ understanding of the particulate nature of matter indicated that students differentially internalize scientific theories and concepts. Students may have a primitive continuous-matter outlook on the physical world, as opposed to the accepted particulate model (11). Students have tendencies to transfer changes in macroscopic properties to the microscopic level. Griffiths and Preston’s (22) study on students’ conceptions of fundamental characteristics of atoms and molecules showed that grade-12 students had 52 misconceptions. They concluded that some of the misconceptions observed were in parallel to the historical developments of scientific concepts. The brief review undertaken here and the broader reviews done by other researchers about students’ conceptions (6, 7, 23) showed that there are common agreements among researchers, such as (i) children have conceptions that are significantly different from the scientific one; (ii) children’s conceptions of underlying concepts influence their understanding of scientific views presented by their teachers or textbook; (iii) traditional instructional methods have little or no effect on changing misconceptions or developing scientific concepts. As stated above, little research has been undertaken about students’ conceptions of introductory concepts, especially in the study context (1). Also, while many findings are generalizable across age levels, across various curricula, and across cultures, others are not. Therefore, this study will help to determine students’ conceptions of the element, compound, mixture, and physical and chemical change concepts with the situation in our own schools. The concepts studied here are
Journal of Chemical Education • Vol. 74 No. 5 May 1997
Chemistry Everyday for Everyone fundamental to any chemistry curriculum and are difficult to introduce (19). The findings may, then, be taken into account to develop the future curriculum and to design appropriate teaching strategies for classroom instruction. Experimental Design A test concerning the aforementioned five concepts, which was developed by one of the researchers in a previous study by using a number of sources of question-banks either national or international (24), was used in this study. The test consisted of two sections. The first contained eight items and was related to three of the concepts, namely, element, compound, and mixture. The second section was about the physical and chemical change concepts, and had eleven items. The test included a mixture of multiple choice and multiple choice with an explanation section items. Also, some test items were further divided to subquestions. The explanation sections of the questions were used to provide further information about students’ conceptions (25). In the first section of the test, the items 1, 2, 3c, 4, and 5d were related to the element concept; 3b and 5b were about the compound concept; and 3a, 5c, 6, 7, and 8 were related to the mixture concept. Although the test items are classified as related to element, compound, and mixture concepts, the respondent needs to have knowledge of all three to adequately answer each question in this section. As a sample, a question in the first section, item 5, is indicated below. How would you classify the following substances as element, mixture and compound? Why? a. salty water is a _____ because ______________. b. pure water is a _____ because ______________. c. air is a _____ because _____________________. d. copper (metal) is a _____ because __________. In the second section of the test, the items 1, 2, the first part of 5 and 10 were about the physical change concept. The rest of the items were related to the chemical change concept and application of knowledge about chemical reactions to everyday situations. Here again, one needs to have the awareness of the both physical and chemical change concepts to respond accurately to each of the items. As a sample of the questions in this section, item 5, which has also been used by other researchers such as Anderson (17), is given below. When a house was newly built, both the hot and cold water pipes in the kitchen were shiny. Before long the outside of these pipes had become dull and tarnished (covered with a thin dark coating). The outside of hot water pipe was more tarnished than the outside of the cold water pipe. What kind of change is this (physical or chemical)? _____________________________________. Suggest how the coating is formed. ___________. The test was administered to a stratified random sample of 556 students (276 boys and 280 girls) across three grade levels at secondary schools (lycées or senior high schools, ages 14–17; 192 students from lycée 1, 180 from lycée 2, and 184 from the lycée 3) of the East Black Sea Region of Turkey. In general, students had not reported any difficulty in understanding the questions when it was piloted. Also, since many of the test items were selected from the different question-banks, it was accepted that they are valid and reliable for this study. A further judgment about
the suitability of the test items for Turkish secondary students was done by a group consisting of two professors of chemistry, three experienced science education researchers, five chemistry teachers, and two research students working toward Ph.D. degrees in the science education department. The test was administered under normal class conditions, without previous warning. The students were also assured that the results of the test would be used only for a research study and would not be given to any official organization or representative, including their teachers. In the analyses of the results, percentages of wrong answers for multiple choice questions were calculated. For the questions with an explanation section, written responses were analyzed in detail to find out the students’ misconceptions. Also, those who gave no response whatsoever were calculated as percentages. These processes were done for the three levels of secondary education. In addition, an overall achievement score for the whole test was calculated to make statistical comparisons between the levels of secondary education. Results The results from the first section of the test are stated in Table 1 and from the second section in Table 2. The results from the tables and from the students’ written explanations are examined for each of the five concepts in detail in the following sections.
The Element Concept Table 1 shows that many of the students from lycée 1 (4–39% for the multiple choice sections and 21–38% for explanation sections) gave wrong answers for questions related to the element concept (questions 1, 2, 3c, 4, and 5d). Further, 2–36% of the students from this level gave no answer. The students’ wrong answers for the same questions from lycée 2 were about 10–23% for the multiple choice sections and 36–42% for the explanation sections. The percentages of students who gave no answer were about 8–31% at this level. At lycée 3, the percentages were 18–31, 35–48, and 15–35, respectively. The Compound Concept The results of test items (questions 3b and 5b) related to the compound concept from the Table 1 indicated that at different levels about one-third of students (lycée 1, 19– 27%; lycée 2, 27–33%; and lycée 3, 33–36%) gave wrong answers. Those who gave no answer were 17–36, 18–29, and 16–29%, respectively, at different levels. In terms of written explanations 39, 34, and 41% of the students gave an explanation that cannot be regarded as a scientific conception. The Mixture Concept The students’ conceptions of mixture were assessed by questions 3a, 5a, 5c, 6, 7, and 8. Table 1 shows that at different levels of lycée, 19–45, 16–31, and 16–44% of students gave wrong answers to the multiple choice sections. For the explanation sections, the percentages of students’ nonscientific reasons were 40–58, 29–52, and 39–50, respectively. The students who gave no answer, with respect to levels of lycée, were 3–36, 2–29, and 4–29%. The Physical and Chemical Change Concept In Table 2, the percentages of wrong answers to the second section of the test (which was related to physical and chemical changes) are depicted. These results indicated that the fewest wrong answers were given to item 1, which
Vol. 74 No. 5 May 1997 • Journal of Chemical Education
519
Chemistry Everyday for Everyone was about selecting one of the multiple choices (item 1: melting ice, heating mercury oxide, burning wood, rusting iron, and burning or heating sugar), and item 10 (in which two events were depicted, the first about the process of heating ice until it was evaporated and the second about the electrolysis of water to obtain hydrogen and oxygen), as a physical change. For item 10, students were asked to suggest which one of the two is a physical and which a chemical change. The percentages of wrong answers varied at lycée 1 between 4 and 50%, at lycée 2 between 8 and 32%, and at lycee 3 between 6 and 28%. The percentages of those who gave no response were 0–28, 2–36, and 6–36 with respect to levels of lycée. Moreover, many students at different levels of lycée showed misconceptions about the concepts under investigation. These nonscientific explanations were at lycée 1, about 31–55%; at lycée 2, about 31–57%; and at lycee 3, about 35–50%.
The Overall Achievement Score In order to statistically test the level of significance between levels of the lycée (senior high school), an overall achievement score was calculated for the whole test for each of the students at different levels. The possible highest score was 100 and each question in the test has a weight in regard to its difficulty. The achievement scores were used to test whether the students at upper levels have more scientific conceptions about introductory chemistry concepts than those at lower levels. The mean scores were, at the first level of lycée, 47.28; at the second level of lycée, 52.36; and at the last year of lycée, 48.15. The statistical test showed that there was no significant difference between the three levels of the lycée. Therefore, it can be concluded that the students at upper levels are no better than those at lower levels of lycées in statistical terms. In fact, the mean score of last-year students was lower than that of the second-year students. This could be due to the fact that students actually forget what they have learned rather than developing more advanced conceptions (26). The results in Tables 1 and 2 also show that in many of the questions, lycée 3 students’ wrong answers are more numerous than at the earlier levels of the lycée. Conclusion Table 1. Percentages of Wrong Multiple Choices (A), Wrong Explanations (B), and No Answers (C) in 1st Section of Test Item No.
Lycée 1 (%)
Lycée 2 (%)
Lycée 3 (%)
The analysis of written responses showed that many students tend to leave the explanation section of the questions blank or repeat some sort of statements from the questions rather than giving any detailed reason. The written responses showed that at all levels, many students were unable to use particular ideas. Also, the high percentages of students’ misconceptions for some of the questions, specifically, question 5 in the second section of the test, indicated that a great proportion of students were unable to apply their chemical knowledge in novel situations. Moreover, many students were unaware of the correct classification of substances met in everyday life as element, compound, or mixture. Some students did not know that air is a mixture of gases and that water and sugar are compounds. On the whole, the results are not pleasant. The mean scores are around 50 in terms of overall achievement. This result alone showed that introductory concepts are not learned well by secondary students. The reason for this many vary from the instructional approaches to the textbook and the availability and use of the laboratory (3). However, one thing that should be mentioned here is that students’ earlier conceptions have great influence on subsequent learning (27). Thus, if we take them into account in planning future activities, the student may develop these concepts more scientifically. These results confirmed the difficulties with introductory concepts experienced by secondary students at different levels of lycée. The earlier researchers’ findings also showed high percentages of misconceptions. For example in English secondary school only 25% of 15-year-olds had acceptable conceptions (19), and in American schools up to 86% of secondary students had misconceptions about the chemical change concept (3). Implication for the Teaching of Chemistry Students’ preconceptions have a great influence on subsequent learning (19, 27, 29). These conceptions not only affect the interpretation of new knowledge but also sometimes make the comprehension of it impossible (27). Such prior ideas (which may be acquired either before schooling or after being in formal education) about the introductory Table 2. Percentages of Wrong Multiple Choices (A), Wrong Explanations (B), and No Answers (C) in 2nd Section of Test Item No.
Lycée 1 (%)
Lycée 2 (%)
Lycée 3 (%)
A
B
C
A
B
C
A
B
C
A
B
C
A
B
C
A
B
1
39
49
30
23
42
21
18
45
35
1
10
—
—
16
—
02
16
—
06
2
08
21
29
18
36
21
17
35
29
2
40
—
20
23
—
18
23
—
16
3a
28
—
36
22
—
29
44
—
29
3
38
38
17
18
24
21
27
21
46
C
3b
19
—
36
27
—
29
36
—
29
4
44
—
10
32
—
16
28
—
14
3c
04
—
34
10
—
31
31
—
25
5
19
55
17
28
57
08
23
50
21
4
10
51
02
05
33
15
10
40
13
6
17
32
28
24
34
36
28
35
36
5a
30
40
12
23
29
08
27
39
09
7
18
31
15
29
31
33
14
35
38
5b
27
39
17
33
34
18
33
41
16
8
20
—
10
12
—
30
08
—
35
5c
45
58
20
31
34
15
42
37
18
9
50
—
10
30
—
28
20
—
32
5d
21
38
10
20
40
08
31
48
15
10a
04
—
13
10
—
07
08
—
27
6
22
—
03
18
—
03
16
—
04
10b
11
—
13
08
—
05
06
—
27 20
7
19
50
20
16
40
20
18
42
19
11a
33
—
15
27
—
18
26
—
8
—
48
30
—
52
26
—
50
33
11b
28
—
12
20
—
14
24
—
18
11c
32
—
21
28
—
13
27
—
25
520
Journal of Chemical Education • Vol. 74 No. 5 May 1997
Chemistry Everyday for Everyone concepts that are building blocks in chemistry (19, 28) must be taken into account in teaching chemistry. This would generate links between the sensory input and existing ideas in the learner’s mind. As a result, students’ misconceptions may be changed towards a scientific view. In fact, as Freberg and Osborne (30, p 83) put it, “…the active construction, testing and subsumption of new ideas can only be accomplished by the learner”. The curriculum developers, teachers, and teacher educators together with researchers in the area of science education should work hand in hand to design appropriate teaching materials and strategies adequate to help develop the introductory concepts. In doing this, everyday events should be commonly used to enable students to apply their chemical knowledge to novel situations. Moreover, students’ ideas may not be influenced or may be influenced in unanticipated ways (28), especially in teaching abstract scientific concepts by using traditional teaching strategies. Since we cannot think of teaching chemistry without hands-on activities, we need to make use of laboratory as much as possible to overcome students’ misconceptions. Overall, the importance of identification of possible sources of misconceptions is clear. If one has this knowledge, then different instructional strategies might be developed according to the type and source of the misconception. Further study of the effect of factors on students’ conception of chemical concepts should be pursued. Literature Cited 1. Ayas, A; Çepni, S; Akdeniz, A. R. Sci. Educ. 1993, 77, 433–440. 2. Ben-Zvi, R.; Eylon, B.; Silberstein, J. Educ. Chem. 1982, 47, 64–66. 3. Abraham, M. R.; Grzybowski, E. B.; Renner, J. W.; Marek, E. A. J. Res. Sci. Teach. 1992, 29, 105–120. 4. Brook, A.; Briggs, H.; Bell, B. Secondary Students’ Ideas about Par-
ticles; CLISP: The University of Leeds, 1983. 5. Gussarsky, E.; Gorodetsky, M. J. Res. Sci. Teach. 1988, 25, 319– 333. 6. Driver, R.; Easley, J. Stud. Sci. Educ. 1978, 5, 61–84. 7. Gilbert, J. K.; Watts, D. M. Stud. Sci. Educ. 1983, 10, 61–98. 8. Benson, D. L.; Wittrock, M. C.; Baur, M. E. J. Res. Sci. Teach. 1993, 30, 587–597. 9. Scott, P. In Proceedings of Second International Seminar on Misconceptions and Educational Strategies in Science and Mathematics; Novak, J. D., Ed.; Cornell University: Ithaca, 1987; pp 404–419. 10. Nusbaum, J.; Novick, S. Instruct. Sci. 1982, 11, 183–200. 11. Novick, S.; Nusbaum, J. Sci. Educ. 1982, 65, 187–196. 12. Hackling, M. W.; Garnett, P. J. Eur. J. Sci. Educ. 1985, 7, 205– 214. 13. El-Gendy, O. E. Ph.D. Thesis, University of Cardiff, 1984. 14. Hand, B.; Treagust, D. F. School Sci. Math. 1991, 91, 172–176. 15. Ross, B.; Munby, H. Int. J. Sci. Educ. 1991, 13, 11–23. 16. Donnelly J. F.; Welford, A. G. Educ. Chem. 1988, 25, 7–10, 14. 17. Anderson, B. Sci. Educ. 1986, 70, 549–563. 18. Mitchell, I. J.; Gunstone, G. F. Res. Sci. Educ. 1984, 14, 78–88. 19. Briggs, H.; Holding, B. Aspects of Secondary Students’ Understanding of Elementary Ideas in Chemistry: Full Report; CLISP: University of Leeds, 1986. 20. Laverty, D. T.; McGarvey, J. E. B. Educ. Chem. 1991, 28, 99–102. 21. Hesse, J. J; Anderson, C. W. J. Res. Sci. Teach. 1992, 29, 277– 299. 22. Griffiths, A. K; Preston, K. R. J. Res. Sci. Teach. 1992, 29, 611–628. 23. Osborne, R.; Wittrock, M. C. Sci Educ. 1983, 67, 489–508. 24. Ayas, A. Ph.D. Thesis, University of Southampton, 1993. 25. White, R.; Gunstone, R. Probing Understanding; Falmer: London, 1992. 26. Van der Borght, C. de B.; Mabille, A. Int. J. Sci. Educ. 1989, 11, 347–362. 27. Mas, C. J. F.; Perez, J. H.; Harris, H. H. J. Chem. Educ. 1987, 64, 616–618. 28. Osborne, R.; Freyberg, P. Learning in Science: The Implications of Childrens’ Science; Heinemann: London, 1985. 29. Herron, J. D.; Cantu, L. L; Ward, R.; Srinivasan, V. Sci. Educ. 1977, 61, 185–199. 30. Freyberg, P.; Osborne, R. In Learning in Science: The Implacation of Children’s Science; Osborne, R.; Freyberg, P. Eds.; Heinemann: London, 1985; pp 82–89.
Vol. 74 No. 5 May 1997 • Journal of Chemical Education
521
