CHILDREN S CONCEPTS ABOUT THE STARS. Mei-Hung Chiu Graduate Institute of Science Education National Taiwan Normal University

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1 CHILDREN S CONCEPTS ABOUT THE STARS Mei-Hung Chiu Graduate Institute of Science Education National Taiwan Normal University Shueh-Chin Weng Ing-Shyan Chern Graduate Institute of Earth Science National Taiwan Normal University Paper presented at the annual meeting for the Australian Association for Research in Education (AARE), 22nd-25th November, 1993, Fremantle, Western Australia. ABSTRACT Twinkle, twinkle, little star... We all have experience staring into the sky to look for twinkling stars. However, have we ever known how much our children know about stars? This study intended to understand our children s conceptions about the stars. In particular, if there are differences between the fourth graders who have not learned the topic about the stars and the seventh graders who learned in a science class. Fourth (n=90) and seventh (n=93) graders in Taipei, Taiwan, were asked to answer a series of open-ended questions about the sizes, shape, components, and movement of the stars. Fifteen fourth graders and sixteen seventh graders were drawn based on their responses to the questionnaire to be interviewed. They were individually interviewed by the researchers to further confirm their mental models. The questions are designed to examine how much students know about characteristics of stars and relationships among the stars, the moon, the earth, and the sun. The data consist of a transcript of each interview and a piece of written work the subject produced. All interviews were videotaped for later transcription and analysis. The findings suggest that the students concepts and explanations of the phenomena of the stars are inconsistent even for those seventh graders who have been taught in a formal science class setting. Their explanations and understandings are based on

2 their incomplete and piecemeal scientific knowledge and daily experiences. In particular, younger children tend to explain the phenomenon according to the framework of the earth. For instance, first, 62.4% of the seventh graders consider the shape of the stars are round, while only 30% of the fourth graders think so. Majority fourth graders (61.1%) considered that the stars blinking, whereas only 16.1% of the seventh graders think so. Second, 56.1% of the seventh graders explain the formation of the stars by providing scientific reasons (e.g., explosion or collision) while only 19.9% the fourth graders give these responses. About one third (33.3%) of the fourth grade students reply I don t know., God made it., Man (or ancient people) made it., or The stars took the light from the sun and the moon., etc. Third, more younger children consider that the star can only be seen at midnight and 3 AM because of its movement, while more older children attribute it to Earth s rotation. OBJECTIVES In order to promote deeper understanding about children s conceptual knowledge about the stars, 183 fourth and seventh grade students were asked a series of questions about the shapes, sizes, distance, and movement of the stars, the sun, and the moon. We are mainly interested in understanding the nature of children s initial knowledge about the stars in the solar system and in finding out how this knowledge changes as children are exposed to school formal training. THEORETICAL BACKGROUND During the past few decades research in cognitive science, science education, and developmental psychology has shown that children construct an intuitive understanding of the world based on their daily experiences and related conceptions. Many different terms have been used to refer to this type of knowledge, namely, preconceptions (Ausubel, 1968), misconceptions (Novak, 1987), alternative frameworks (Driver & Easley, 1978), mental models (Collins & Gentner, 1987), intuitive theories (McCloskey & Kargon, 1988), and theory-like (Carey, 1985). Although different terms were given, there is a general agreement that this intuitive knowledge provides explanations of natural phenomena which are frequently different from the scientific explanations. Also, these intuitive knowledge tend to be robust and resistant to change (Chi, 1992; Vosniadou and Brewer, 1992). In this paper, we would address children s knowledge structures in terms of mental models because we consider these models to be more appropriate to represent what we found from the study. The following is to briefly discuss the characteristics of mental

3 models and children s knowledge acquisition in astronomy.ˇ Mental model Viscuso and Spoehr (1986) have given a definition to mental models after reviewing research in cognitive science, science education, and developmental psychology. First, mental models are runnable. They allow the user to make mental simulations of situations and events, and make predictions about how changes in one part of a system will affect the other parts. Second, since the propagation of such effects throughout an entire system must be simulatable, a mental model contains topographical or connectedness information. Third, causality is inherent in a mental model since the propagation of change across the simulated system implies causal links. And fourth, because causal propagation makes it possible to make inferences about the functions of different parts of the system, a mental model thereby contains functional information. Williams, Hollan, and Stevens (1983) also point out that basically a mental model is a combination of some runnable objects or mental entities. In this mental model, there exists a specific association, parameters, and procedures among the objects for making inference and problem solving (Holland et al., 1986). Experts use this multiple characteristics model to decide when, where, and how it can be used correctly in the process of solving problems.ˇ Knowledge in astronomy This area was chosen because several research has shown that children s knowledge about astronomy projecting consistent results across countries and usually, this knowledge interacts with children s daily experiences heavily (Vosniado and Brewer, 1989; Vosniado and Brewer, 1992). While most of the science education research in astronomy emphasizes on children s concepts of the earth and the sun, very limited studies are found on children s concepts of the star. For instance, Vosniado and Brewer (1989) found that most of the younger children thought that the earth is bigger than the sun, the moon and the stars. But, it is interesting to note that the change to the Copernican model goes through an intermediate stage where children believe that the earth is smaller than the sun but bigger than the stars. Some children believe that sun and the stars are bigger than the earth and the moon. Nussbaum (1986) also found that pupil knowledge about the earth is elementary and piecemeal. Model communications media did not seem capable of bringing man s considerable knowledge of the universe to the schools. Finegold and Pundak (1991) administered a multiple choice test to identify and categorize school students conceptual frameworks in

4 astronomy and examined students level of knowledge and conceptualization from grades 7 through 12. They found that junior high students conceptualization is mainly geocentric; students at this level tend to explain observed astronomical phenomena relative to the framework of the earth, as did the ancient Greeks. However, high school students showed progress toward a heliocentric explanatory framework. In this study, we attempt to uncover what the children s conceptions about the star and how students use their conceptual framework to answer questions which is highly related to their daily experiences. We hope our finding could further help students learning and design meaningful instructional materials. METHOD In this paper, open-ended questionnaires were used to test children s concepts about the star. Individual interview techniques and simulated models were also employed to investigate how they arrived at the answers. The following are brief descriptions of the study. Subjectsˇ The study was conducted in Taiwan. Our subjects included 90 fourth (boy=43, girl=47) and 93 seventh (boy=49, girl=44) graders. The average age for the fourth graders is 9 years and 9 months old (ranging from 8 years and 9 months old to 11 years and 2 months old). The average age for the seventh graders is 12 year and 6 month old (ranging from 12 year-old to 13 years and 6 months old). The subjects came from middle-class backgrounds and attended schools in Taipei county. Materialsˇ Children s knowledge of observational astronomy was examined using an elaborated verbal questionnaire which included questions about the shape, size, composition, motion, and location of the stars, the sun, the earth, and the moon. The questionnaire has 12 test items covering those main topics as described above. The questionnaire was developed through a pilot study and the supplemented with explanatory questions (Why the stars looks shining?) and generative questions (e.g., If you see the stars above your head at midnight, where would it be at 3 AM? ). Processˇ The subjects were asked to answer opened-ended questions regarding to the nature of the stars. Then Fifteen fourth grader and sixteen seventh grade students were selected for interviewing based on their special and interesting explanations to the questions. The purpose of the afterward interview was to further confirm children s explanations about their responses. Few more questions were added to request the interviewees to explain

5 phenomenon with models. All the process of interview was videotaped for later translation and data analysis. RESULTS This report will only be covering one small part of the major study. As described before, after the questionnaire, we also used interviewing technique and models to further investigate children s conceptions about the stars and its relationship between the sun and the moon. However, in this paper, we will limit our presentation in some preliminary findings from the questionnaire. The shape of the stars.ˇ The students were asked to describe the shape of the stars. Table 1 presents the fourth and seventh graders responses to the question. It reveals that 62.4% of the seventh graders considered the stars are round. Among them, 41.9% considered that the surface of the stars have some holes, just like the surface of the moon. However, 61.1% of the fourth graders thout that the stars are stary blinking and all of them were unable to provide any descriptions for the surface of the stars. Relative sizeˇ Table 2 shows the responses of the fourth and seventh graders to the question Please list the order of the sizes of the sun, the earth, the moon, and the stars.. About 75.3% of the seventh graders were able to show sun > earth > moon while only 34.4% of the fourth graders were correct. Within each grade, majority of students considered that the stars are smaller than the sun (33.3% for the fourth graders and 55.9% for the seventh graders respectively). Not surprisingly, there is a quite large group of fourth graders (43.3%) considered that the earth was the biggest (earth > sun > moon) which was consistent with other research results in astronomy (Vosniado and Brewer, 1989). Table 3.1 indicates that among the 55.9% of the seventh graders, 41.9% of them consider the stars were the smallest as opposed to 28.9% of the younger children. Also, there were 11.8% of the older children considered the stars can be smaller than the sun but bigger than the earth and the moon. Even though more than 10% of the students from both grades considered the moon is bigger than the earth, again, most of them still considered the stars are the smallest (see Table 3.2). This finding suggests that our students simply use their intuition and observational experiences to judge the scientific phenomenon.

6 As described before, we also interviewed some students to examine their mental models about if the star can be seen at different time frame. We present here with some premitive results from the interview. Basically, there are five types of students conceptions about the relationship between the sun, the earth, and the star in terms of their movement and. The five types are: Type I: None of the sun, the earth, and the star Type II: The star moves but the earth does not. Type III: Both the star and the earth move. Type IV: The earth moves but the star does not. Type V: Correct mental model of the phenomena.ˇ moves. Figure 4. The earth moves but the star does not. IMPLICATIONS The findings from this study show that the younger children explain the observational astronomy based on their own personal experiences or their imagination while the older children are able to apply their scientific knowledge to the phenomenon and provide logical explanations to the problem situations. Also, the younger children see the solar system from their own personal points of view so that about half of them considered the earth is biggest among the sun, the moon, and the stars. Knowing children s conceptions about the stars, we, as science educators, might be able to design some instructional aids for helping them construct meaningful and useful mental models to learn astronomy. REFERENCE Ausubel, D. P. (1968). Educational psychology: A cognitive view. New York: Holt, Rinehart, & Winston. Carey, S. (1985). Conceptual change in children. Cambridge, MA: MIT Press. Chi, M. T. H. (1992). Conceptual change within and across ontological categories: Examples from learning and discovery in science. In R. Giere (Ed.), Cognitive models of science (Minnesota studies in the philosophy of science, vol 15, ). Minneapolis: University of Minnesota Press. Driver, R. & Easley, J. (1978). Pupils and paradigms: A review of literature related to concept development in adolescent science students. Studies in Science Education, 5,

7 Finegold, M. & Pundak, D. (1991). A study of change in students conceptual frameworks in astronomy, Studies in Educational Evaluation, 17, Gentner, D. & Stevens, A. L. (Eds.). (1983). Mental models. Hillsdale, NJ: Erlbaum. Holland & N. Quinn (Eds.) (1986). Cultural models in thought and language. Cambridge UK: Cambridge University Press. McCloskey, M. (1983). Naive theories of motion. In D. Gentner & A. L. Stevens (Eds.), Mental models. Hillsdale, NJ: Erlbaum. Nussbaum, J. (1986). Students perceptions of astronomical concepts. Proceedings of the GIREP Conference, Copenhagen. Viscuso, S. R. & Spoehr, K. T. (1986). How does a mental model facilitate comprehension of instructions? Paper presented at the annual meeting of the Psychonomic Society, New Orleans, LA, November. Vosniadou, S. and Brewer, W. F. (1992). Mental models of the earth: A study of conceptual change in childhood, Cognitive psychology, 24, ˇ Vosniadou, S. and Brewer, W. F. (1989). A cross-cultural investigation of children s conceptions about the earth, the sun, and the moon: Greek and American data. In H. Mandl, E. DeCorte, N. Bennett, & H. F. Friedrich (Eds.), Learning and instruction: European research in an international context (vol. 2.2, ). Oxford: Pergamon. Williams, M. D., Hollan, J. D., & Stevens, A. L. (1983). Human reasoning about a simple physical system. In D. Gentner & A. L. Stevens (Eds.), Mental models. Hillsdale, NJ: Erlbaum. Table 2. Percentage to the question What is the order of the sizes of the sun, the earth, the moon, and the stars. Table 3.1 Sub-analysis to sun>earth>moon when stars Table 3.2. Sub-analysis to sun>moon>earth when stars Relative distanceˇ Table 4 presents the percentage of responses to the question regarding to the relative distances of the earth, sun, moon, and

8 stars. 87.2% of the seventh graders know the sun is farther than the moon as opposed to 58.9% of the fourth graders. 54.9% of the seventh graders considered the stars are even farther than the sun, whereas there are only 22.3% of the fourth graders thought so. There were similar percentages of the fourth and seventh graders considered the stars are closer to the earth than the sun or even than the moon, 36.6% for the fourth graders and 32.3% for the seventh graders respectively. Surprisingly, we found that over one fifth of young children considered the sun is the closest (22.2%). This might have something to do with the size of the sun which is relatively larger than the moon and the stars. Table 4. Percentage of responses to the question What is the correct order of the earth, sun, moon, and stars if we arrange them according to size? by grade level. ˇ Formation of the starsˇ Table 5 indicates that 56.1% of the seventh graders were able to use scientific explanations to interpret how the stars were formed, such as explosion, collision, or cluster. However, only 19.9% of the fourth graders attributed the cause to these factors. For those younger children, they tended to answer the question by providing responses like myth, by its nature, from other planets, by meteorite, I don t know., and so on. Table 5. Percentage of responses to the question What causes the formation of the stars? Why the stars shine? ˇ Table 6 indicates that 40.9% of the seventh graders replied that the stars can shine from its own body while only 18.7% of the fourth children thought so. We have to note that 42.2% of the younger children considered the stars reflect the sunlight whereas only 26.9% of the seventh graders used this interpretation. Also, over 1/5 of the fourth graders were unable to give explanations. The stars are created by God, Man, ancient people, scientists, or absorbing the essence of the sun and the moon. Table 6. Percentage of responses to the question Why the stars shine? Do the stars move?ˇ This is a set of question about an event. The questions were

9 formed as follows. (1) Can you see the star at 3 AM if it was above your head at midnight? Please explain why. (2) Can you see the same star at noon? Please explain why. Among 93 seventh graders, 71.1% of them replied Yes. to the first question and 59.1% of the fourth graders did so. 23.8% of the seventh graders said NO as opposed to 33.4% of the fourth graders (See Table 7). Most of them were able to provide with some explanation except a low percentage of them. Only few were unable to provide with yes or no answer (6.7% for 7th and 5.4% for 4th graders respectively). Table 7 shows reasons that the students gave when they answered Yes. to the question (1). Among 93 seventh graders, there were 21.5% of the older children able to attribute the phenomena to earth s rotation whereas only 1.1% of the fourth graders were able to do the same. About one fourth of the fourth graders considered that the star has moved to where we could not see it. Table 7. Percentage of responses to the question of Can you see the star at 3 AM if it was above your head at midnight? Please explain why. For the second question, although very high percentages of our subjects answered No. (94.7% for the seventh and 82.3% for the fourth graders, see Table 8), the distributions of the percentages of their answers were quite different. Besides a relatively high percentage goes to The sunlight is too strong. (50% for the fourth graders and 47.3% for the seventh graders respectively), 21.5% of the seventh graders were able to use earth s rotation to explain it and there was even 10.8% of the older students were able to provide with a more complete answer (rotation and sunlight). However, there were 17.8% of the younger children used story-telling strategy to explain the phenomenon. Finally, it is quite reasonable to find that very few subjects considered that the star can be seen at noon. Table 8. Percentage of responses to the question of Can you see the same star at noon? Please explain why. Mental models of an astronomical eventˇ ˇˇˇ Note: 6.7% of 4th graders and 5.4% of the 7th graders did not provideanswers.

10 Note: 8.9% of the fourth graders and 4.3% of the seventh, graders did not provide answers. Figure 1, a typical example by a young child, 401 (first digit stands for the grade and the other two digits for observational number), indicates that none of the sun, the earth, and the star moves. The reason we cannot see the star at noon is simply because the sunlight is too strong (The circle on the left hand side represents the sun, regardless of its size. The circle with a stick (as a person) on it represents the earth. The smallest circle represents the star.). Figure 1. None of the sun, the earth, and the star moves (three 4th graders). Subject 401 S: We cannot see the star because the sun light is too strong. Figure 2 shows that the younger children tended to consider the earth is the largest planet and it does not move in this event (same as subject 401). As you can see, the young child (404) does not take the sun into account as shown in Figure 1. The star is always above the person (stick) although it moves slightly from time to time. This information supports what we have discussed earlier about lacking of the knowledge of earth s rotation and making the use of egocentric viewpoints. Figure 2. The star moves but the earth does not graders). Subjec 404 (ten 4th S: The star can been S: We cannot see seen at east. the star at west because of the strong sunshine. About one third of the seventh graders considered both the star and the earth move (see Figure 3) while none of the fourth graders thought so. Due to the earth moves slower than the star moves, we were unable to see the star in the sky at noon. Even though the students have the concept of earth rotation, they were unable to relate it to the situation. Therefore, they attribute the incorrect cause to this event. Figure 3. Both the star and the earth move (five 7th graders).

11 Figure 4 shows that the students (two 4th and eight 7th graders) consider the star stays constantly at the same place. The reason we were unable to see the star is because the earth rotates so that we are not at the right place for it. Finally, the Figure 5 indicates a mental model held by a seventh grader, the subject 703, which not only does he use the correctly relative sizes to represent the sun, the earth, and the moon, but he also takes the light source into account to show their relationships of position. Only seventh graders were found for this type. Figure 5. Correct mental model of the phenomena (four 7th graders).

REASONING PROCESSES UNDERLYING THE EXPLANATION OF THE PHASES OF THE MOON.

REASONING PROCESSES UNDERLYING THE EXPLANATION OF THE PHASES OF THE MOON. Shamin Padalkar and K. Subramaniam Homi Bhabha Centre for Science Education (TIFR) Mumbai OBJECTIVES AND SIGNIFICANCE OF THE STUDY