Research: Science and Education edited by
Chemical Education Research
Diane M. Bunce The Catholic University of America Washington, DC 20064
Amy J. Phelps Middle Tennessee State University Murfreesboro, TN 37132
Two Kinds of Conceptual Problems in Chemistry Teaching
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Zuzana Haláková* and Miroslav Proks ˇa Department of Didactics, Psychology and Pedagogy, Comenius University in Bratislava, Mlynská dolina, 842 15 Bratislava, Slovakia; *
[email protected] Many students today believe that to have an idea of what the concept means is enough. They memorize the definitions of some concepts or phenomena in chemistry verbatim. Some weeks later they are able to learn another definition for the same phenomena in another subject using other words. Why do they do this? Why do they accept new information separately from the older information? What could we do to help students to understand, rather than to memorize, and to be able to use what they have learned? In chemistry a great deal of attention has been paid to conceptual questions and to students’ success in solving these kinds of problems compared to algorithmic questions that are mathematically defined and that are solved mostly through the use of algorithms. Conceptual questions present a chemical situation that students have not been trained in. They ask the students to justify a choice, to predict what happens next, to explain why something happens, to explain how something happens, to link two or more areas or topics, to recognize questions phrased in a novel way, and to extract useful data from an excess of information. They require students to synthesize answers or to evaluate a problem in order to select the mathematical tools necessary to arrive at an answer (1). Conceptual understanding is required for solving conceptual questions (2). Conceptual questions can take many forms and types. In our research we used a “pictorial” form (we tried to express information pictorially or graphically) and a “verbal” form (we used the written words without pictures for describing the problem). Robinson and Nurrenbern (1) introduce six types of conceptual questions: (i) tiered multiple-choice questions consisting of a pair of questions that ask students what will happen in the first question and ask them to provide a reason in the following question, (ii) particulate questions representing chemical situation on the atomic or molecular (particulate) level using circles or spheres of different sizes or colors, as necessary, to represent the particles, (iii) solving laboratory questions where students use graphs, tables, and other data to predict or to explain what happens in an experimental situation, (iv) demonstration questions asking students to answer questions having observed a demonstration, video, or simulation, (v) analogy questions that are based on completing an analogy (A is to B as C is to D), and (vi) series completion questions that ask students to select an item that best completes a series. The use of conceptual questions is one tool that can assist students in obtaining a deeper learning experience, improve their understanding and ability to apply learning to 172
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new situations, enhance their critical thinking, and increase their enthusiasm for science and learning. In addition, conceptual questions extend assessment beyond “What does a student remember?” and “What can a student do?” to “What does a student understand?” Conceptual questions also provide one route for diagnosing student misconceptions (3). The opinion that the ability to solve a conceptual problem indicates understanding of chemical concepts has dominated the literature for some time. Students often solve numerical problems successfully using memorized algorithms, although the meaning is hidden from them. This is the reason studies have focused on students’ conceptual knowledge in chemistry instead of the numerical problem-solving methods. Earlier research was focused on the particulate nature of matter (4), chemical equations (5), gas laws and stoichiometry (6, 7), and density and empirical formulas (2). These studies all found that student conceptual knowledge lags far behind their algorithmic problem-solving skills. Many students who solve mathematical problems successfully do not understand the chemical concepts behind memorized algorithms. They simply memorize and repeat skills without being able to visualize and comprehend the concepts (8). Recent Studies There have been many studies aimed at students’ conceptual knowledge in chemistry. Pickering (9) showed that students at Princeton reached only a 38% success rate on conceptual problems while the success rate for traditional numerical problems was 95%. The author concluded that students should be able to solve conceptual problems and suggested that these problems should be integrated into instruction frequently. Nurrenbern and Pickering (6) showed that students are able to solve traditional problems on gases, but they are not able to solve the same problems assigned as a diagram, that is, in pictorial form. Similarly, students are successful in solving traditional stoichiometry problems, but they have trouble writing the chemical equations given a diagram of a reaction. This result is consistent with the findings of Yarroch (5) and Gabel and co-workers (4). Sawrey (7) replicated the Nurrenbern and Pickering study with a larger group of students. She separately studied student success on conceptual versus numerical problems for the top and bottom of the class to see whether the effect disappears for the higher achievers. A statistically significant difference appeared between success in traditional and conceptual questions.
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Research: Science and Education
Table 1. Pictorial and Verbal Question Comparisons
water oxygen hydrogen
Task
? evaporated water
liquid Water
?
= A
B
C
E
D
The magnified view of a very small portion of liquid water in a closed container without any air would show us the molecules of water. What would the magnified view show after the water evaporates? a. molecules of oxygen and molecules of hydrogen b. some water molecules, atoms of oxygen, and atoms of hydrogen c. nothing, no particules would be noticed d. atoms of oxygen and atoms of hydrogen e. water molecules, but less than in liquid water Figure 1. Example of a pictorial question (top) and the corresponding verbal question (bottom).
Pickering (9), Nurrenbern and Pickering (6), and Sawrey (7) obtained similar results regarding student success with conceptual questions at a rate of 38%. Nakhleh’s research (2) showed that 85% of students (N = 1090) were good algorithmic problem solvers while only 49% of the students were successful in solving conceptual questions from the same area of general chemistry. Researchers from around the world including those in Australia, Israel, and Taiwan have obtained results to support that students are better at solving algorithmic problems than conceptual ones (10–12). We would like to know why the studies show this tendency. Are conceptual questions more difficult to solve? They reflect students’ understanding, not their ability to follow memorized algorithms without logical thinking. The conceptual question could be formatted in a different way. Recent studies have focused on pictorial forms of conceptual questions (4, 6, 8, 13–15), but it is also possible to create the questions in verbal form using only words without pictures to describe the problem (2). Our Research We have been influenced by a multiple-choice test created by Nurrenbern and Robinson (3), which could indicate the level of students’ misconceptions in chemistry. The test was administered to over 1400 students in a general chemiswww.JCE.DivCHED.org
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Success Rate (%) (N = 61)
χ2
Pictorial Items
Verbal Items
1
26.20
08.20
6.96a
2
49.20
57.40
0.82
3
23.00
24.60
0.04
4
49.20
41.00
0.83
5
34.40
68.90
14.47a
6
62.30
77.10
3.14
7
11.50
19.70
1.56
8
62.30
29.50
13.20a
9
42.60
36.10
0.55
10
21.30
36.10
3.24
11
11.50
16.40
0.61
12
32.80
57.40
7.45a
13
26.20
23.00
0.18
14
36.10
44.30
0.85
Statistical significance at p < 0.05.
a
try course for science and engineering majors (all of whom have had a high school chemistry course). The average grade on the test were 45% (10 of 22) in the fall and 50% (11 of 22) the following spring (3, 16). In connection with these results we are interested in whether or not the results of the conceptual test were influenced by the pictorial form of the questions. We wanted to know whether the unfamiliar pictorial forms were unnecessarily complicating the questions. Methodology We modified Robinson and Nurrenbern’s original test (3), into 14 multiple-choice questions. Every question was made in both forms: pictorial and verbal. An example of one pictorial and verbal question is given in Figure 1. The content of each pair of questions was the same. Two variations of the test were created, each containing 7 pictorial and 7 verbal conceptual questions. Each question had one correct answer. Sixty-one students were randomly assigned to two different groups. They solved the test simultaneously within 30 minutes. We were interested in the comparison of the students’ success rate in solving pictorial conceptual questions versus verbal conceptual questions. Data Analysis The results for each individual question of the test are shown in Table 1. We computed χ2 (chi-square) for each comparison and in four cases found the difference to be significant at the p < 0.05 level. In the majority of questions (2–4, 6, 7, 9–11, 13, and 14) the choice of the right answer does not appear to depend on the form of the question. The choice of the right answer is connected with a particular form of the question in 4 cases. Students were more likely to choose the wrong answer in the verbal form than in the pictorial form on questions 1 and 8, whereas questions 5 and 12 showed a statistically significant higher frequency of right answers for the verbal form.
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Research: Science and Education
Results Our sample consisted of 122 first-year students. These students are inclined to study natural science (chemistry, biology, geography, etc.) further and would like to teach these subjects at secondary schools in the future. The test was given to students at the beginning of the fall term. The overall average score on the test was 36.71% with a verbal item score of 38.52% and a pictorial item score of 34.89%. The results correspond with the previous research. The success rate is low for both the verbal questions and the pictorial questions. These results gave us reason to suppose that there is another factor that is more important than the form of the question. It was possible for students to guess the right answer even if they had no idea about the question. They often did not choose a logical or reasonable answer but were more likely to pick a familiar but incorrect answer. We examined the data in terms of students’ chemistry interest. Students who would like to continue their chemistry studies achieved 39.39% success overall, 41.13% on verbal questions and 37.66% on pictorial questions. Students without special chemistry interest achieved 35.71% overall, in the verbal questions 37.56% and in the pictorial questions 33.87%. There were not any statistically significant differences between compared samples. Based on these results we cannot say anything about what leads to success in solving these problems but our data show that question form has little effect on success, which is important. Perhaps the low performance on these conceptual questions, whether they are pictorial or verbal, is associated with a lack of conceptual understanding on the part of the students. The students’ conceptual understanding is what the questions were trying to assess and this kind of understanding is essential for many other science disciplines. The level of understanding of general chemistry concepts is not as high as expected for students who are successful at solving questions that involve algorithms. We should think about these alarming test results. Is it the nontraditional form or the understanding of content reflected in the outcome? If the problem lies in the question form, we would have expected to find differences between the success in solving the verbal and the pictorial conceptual problems. One form should be better than the other one. Our data indicate that it is likely that the content and the lack of conceptual understanding are playing an important role in these results. Conclusion Results of our research do not indicate a preference for either of the two types of chemical conceptual questions. The verbal form of the question in comparison with the pictorial form does not always provide the better method for students to achieve success on the test. There are some other factors: a long verbal question could exhaust a student before the student is able to understand the point of it. The choice of words could be too complicated and in many cases it is more useful to substitute the text for the picture. On the other hand, the picture is not always clear and the student may not pay enough attention to it because it is just something in addi174
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tion to the text. We chose to test the two extremes of the question form: in strictly verbal form and strictly pictorial form. We cannot speak to the combination of these two types, although it could be a key reason for students’ success. In our opinion, the low success rate on the test in our research is caused mainly by the difficulties with content and a lack of conceptual understanding. The form (verbal or pictorial) was not important and did not have a great influence on student success. We realize that students’ experiences and knowledge are important in determining whether they consider a question conceptual or algorithmic. The more opportunities given to them the better their ability to solve these kinds of chemical problems. We hope to help them imbibe new experience and knowledge and enrich their minds. Conceptual questions may be one way to do so. Acknowledgment This work was supported by Ministry of Education of Slovak Republic (Grant Vega No.1/0030/03). W
Supplemental Material
The two versions of the conceptual tests are available in this issue of JCE Online. Literature Cited 1. Robinson, W. R.; Nurrenbern, S. C. Conceptual Questions (CQs). http://jchemed.chem.wisc.edu/JCEDLib/QBank/collection/ CQandChP/CQs/WhatAreCQs.html (accessed Aug 2006). 2. Nakhleh, M. B. J. Chem. Educ. 1993, 70, 52–55. 3. Robinson, W. R.; Nurrenbern, S. C. Conceptual Questions (CQs). http://jchemed.chem.wisc.edu/JCEWWW/Features/ CQandChP/CQs/CQIntro.html (accessed Aug 2006). 4. Gabel, D. L.; Samuel, K. V.; Hunn, D. J. Chem. Educ. 1987, 64, 695–697. 5. Yarroch, W. L. J. Res. Sci. Teach. 1985, 22, 449–459. 6. Nurrenbern, S. C.; Pickering, M. J. Chem. Educ. 1987, 64, 508–510. 7. Sawrey, B. A. J. Chem. Educ. 1990, 67, 253–254. 8. Smith, K. J.; Metz, P. A. J. Chem. Educ. 1996, 73, 233–235. 9. Pickering, M. J. Chem. Educ. 1990, 67, 254–255. 10. George, A.; Masters, A.; Prabhakar, C. Manipulating Chemicals Equations—the Bête Noire of Junior Chemistry Students. http://www.itl.usyd.edu.au/itl/Showcase2001/docs/GEOR28.pdf (accessed Aug 2006). 11. Ashkenazi, G. Learning Style, Personality Type and Academic Achievement in Learning Style. http://www.fh.huji.ac.il/~guy/ projects/FourTypes.html (accessed Aug 2006). 12. Chiu, M.–H. Algorithmic Problem Solving and Conceptual Understanding of Chemistry by Students at a Local High School in Taiwan. http://nr.stic.gov.tw/ejournal/ProceedingD/ v11n1/20-38.pdf (accessed Aug 2006). 13. Mas, C. J. Furio; Perez, J. H.; Harris, H. H. J. Chem. Educ. 1987, 64, 616–618. 14. Nakhleh, M. B.; Mitchell, R. C. J. Chem. Educ. 1993, 70, 190–192. 15. Sanger, M. J.; Badger, S. M. J. Chem. Educ. 2001, 78, 1412– 1416. 16. Mulford, D. R.; Robinson, W. R. J. Chem. Educ. 2002, 79, 739–744.
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