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SULAIMAN M. AL-BALUSHI

FACTORS INFLUENCING PRE-SERVICE SCIENCE TEACHERS’ IMAGINATION AT THE MICROSCOPIC LEVEL IN CHEMISTRY Received: 5 April 2008; Accepted: 13 January 2009

ABSTRACT. This study explores the mental images at the microscopic level of matter created by 22 preservice science teachers in Oman. Participants were encouraged during a guided imagery session to construct mental images for a scenario written about the explanation of the reaction of sodium in water. They were then asked to describe what they envisioned in their own imagination. Participants had images that were based on textbook illustrations, modeling kits, a solar-system model, physical properties, and humanized animations. 3D mental images represented 33.36% of participants’ mental images at the microscopic level, while images in 2D format formed 39.15% of the overall created mental images. Several factors shaped the participants’ mental images, such as their imaginative ability, attention mode, and the nature of their old images stored in their long-term memory. Most of the participants experienced image transformation from one form to another as they were progressing in the GI session. This unstable reliance on different models might indicate unorganized conceptual networks in learners’ LTM: a feature that characterizes novices’ mental networking. On the contrary, past research has revealed that experts have more organized and sophisticated conceptual networking. This study argued that participants lacked the homogeneous and reliable mental model of the atom that is required to carry out advanced cognitive processes for mental exploration of chemical phenomena. The absence of this mental model might explain the overwhelming finding in literature that many learners fail to explain and predict chemical phenomena. KEY WORDS: chemistry teaching, guided imagery, imagination, mental images, particulate level of matter, science education

Past research has revealed that students experience a challenge in their attempt to grasp chemical concepts (Ozmen, Demircioglu, & Coll, 2007). This is because the understanding of these concepts demands a deep familiarity with the interactions of the micro-particle at the microscopic level (Day, 2004; Harrison & Treagust, 1996; Vos & Verdonk, 1996). Even if they solve some chemical problems, they do not go beyond arithmetic manipulations. The understanding of chemical principles behind the equations and formulas is absent (Gabel, Sherwood & Enochs, 1984). Imagination at the microscopic level has been the enigma behind many breakthroughs in science (Black, 2005; Gooding, 2004; Mathewson, 1999; Shepard, 1988). This ability inspired Michael Faraday to sketch the magnetic field without any mathematical equation, James Watson to discover the three-dimensional double helical structure of DNA, Nikola International Journal of Science and Mathematics Education (2009) 7: 1089Y1110 # National Science Council, Taiwan (2009)

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Tesla to invent the self-starting alternating current motor, Albert Einstein to put down his theory of relativity, and Friedrick Kekule to discover the benzene ring structure (Shepard, 1988). IMAGERY

IN

SCIENCE EDUCATION

Scientific mental imagery becomes increasingly important as scientists continue probing levels of reality that cannot be accessed by human eyes (Czolpinski & Babul, 2005). An ability in imagery plays an essential role in facilitating students’ science learning (Stephens & Clement, 2006; Hegarty, 2004;). Mayer and Sims (1994, cited in Yang, Andre, Greenbowe & Tibell, 2003) assert that students must be guided to develop adequate representations in both the visual (imagery) and verbal processing systems in order to construct explanatory understandings of scientific theories. Stephens & Clement's (2006) study of science students’ reasoning revealed that dynamic mental imagery is an important element of students’ reasoning in science. Hegarty (2004) found that reasoning in mechanical physics involves mental simulation, and it is more dependent on metal spatial representation than it is dependant on verbal ability. Imagery was found to be the major strategy used by learners to solve the problem of gears and pulley systems. Nemotko (1990) found that pictorial lecturing produced better learning results for female college biology students with high imagery abilities, and that non-pictorial treatment was better for low imagers. These visual animations facilitate students’ creation of imagery representations of key scientific concepts, schemata, and processes and improve learning science texts. This unique opportunity offered by interactive visualization to promote the active creation of mental images is highly supportive of intuitive scientific understanding (Czolpinski & Babul, 2005; Yang et al., 2003). Lord (1990) devised a set of guided imagery exercises to train low visual-spatial first-year college biology students to imagine threedimensional shapes and mentally manipulate them. The results indicated that guided imagery training significantly enhanced low visual-spatial students’ performance in both the practical and content knowledge of the biology course. In addition, Naveh (1985) found that guided imagery experience elicited positive attitudes toward science and science classroom activities. Connolly (1994) explored the effects of instructor provided mnemonic imagery on the learning of science content and problem solving. College

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students were encouraged to create mental images of specific physics equations and their applications. The results showed that mnemonic imagery instruction resulted in a significantly higher performance on both formula recognition and multi-step problem-solving tests. Scruggs, Mastropieri, Levin and Goffrey (1985, cited in Connolly, 1994) reported similar results when they compared students’ memory of science facts using mnemonic imagery with students receiving only direct instruction. The results revealed that the mnemonic imagery technique produced an improvement in correct responses. Furthermore, the spatial visualization ability, which is an essential component of mental imagery (Kozhevnikov, Motes & Hegarty, 2007), has an impact on students’ science learning abilities. Past research indicated that students with high spatial ability benefited more from animations of chemical reactions (Yang et al., 2003) and were more able to solve kinematics physics problems (Kozhevnikov et al., 2007) than those of lower spatial ability. Lord (1990) reported that approximately 75% of the A grades in the science courses were earned by students with high spatial ability. Low spatial students generally obtained grades at the lower end of the evaluation scale. These students also have more difficulty with the interpretation of graphs, charts, and tables. Higher spatial ability apparently helps students in understanding chemistry principles and reactions that require mental manipulation of molecules in three-dimensional space (Coleman & Gotch, 1998; Pribyl & Bodner, 1987). Yang et al. (2003) argued that students with high spatial ability may implement imagery strategies more successfully than students with lower spatial abilities. These findings strongly suggest that students who have difficulty creating and controlling mental images are at a disadvantage in science classes. Preservice Science Teachers’ Mental Modeling: Science teachers play a significant role in shaping their students’ mental models. Thus, this study focused on preservice science teachers’ mental images. These prospective teachers will have an impact on their future students’ mental images in science. Therefore, studying pre-service teachers’ mental images has a significant value in designing related experiences in their teacher education program. Previous research of science students’ mental models indicated that students’ mental models tend to be similar to their teachers’ mental models (Apollonia, Chales & Boyd, 2004). Hmelo-Silver & Pfeffer (2004) reported that preservice science teacher’ mental models of aquaria as a complex system did not

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differ from those of middle school students. Van Driel & De Jong (2002) also found that preservice science teachers’ knowledge of scientific models was limited and diverse. Valanides & Angeli (2006) reported that preservice science teachers’ mental models about science content and about epistemological aspects of scientific modeling were naïve or over-simplistic. Valanides & Angeli added that pre-service teachers’ mental models shaped their teaching practices. Taylor & Coll (2002) studied preservice science teachers’ models of kinetic theory. The results indicated that some pre-service teachers’ models were in agreement with the scientific models, some were incomplete, and some were not clear. Out of the research done on guided imagery in science teaching, none of the studies that explored student mental images while being involved in imagery tasks has reached the researcher. What do students see while closing their eyes and listening? What are the characteristics of these images? How do they process the information at the particulate level? How do they mentally shift between the different levels in chemistry: macroscopic, microscopic, and symbolic? These questions and some others were the focus of this investigation. For the purpose of this study, guided imagery and interviews were both used in combination to explore the nature of mental images created by science student teachers while taking an imaginary journey into the micro-worlds of atoms and molecules. Guided imagery is a mental journey in the form of a story. One of the most important advantages of stories is that they involve an active learning by opening up the possibility of involving the imagination and participation of the learner (Hadzigeorgiou & Stefanich, 2000). Brunner (1986, cited in Hadzigeorgiou & Stefanich, 2000) stated that many scientific and mathematical hypotheses start their lives as little stories or metaphors, and that a scientific theory and a wellmade story are two forms of an “illusion of reality”. Therefore, this study is an attempt to describe the nature of students’ imagination in chemistry; the nature of the images they process (in terms of color, size, shape, etc…); the nature of their cognitive processing during guided imagery; the senses they incorporate during the processing; the influence of past experiences; and the mobility across the levels of chemistry: sensory (macroscopic), particulate (microscopic), and symbolic. These are the elements of tacit knowledge, which is rarely the focus of the study of students’ ideas in science education (Day, 2004; Reiner & Gilbert, 2000). Tacit knowledge is difficult to put into words. This study reveals that the use of both guided imagery and interviews in combination is an effective way to uncover the elements of

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tacit knowledge, and construct a clearer picture of students’ imagination in chemistry.

PURPOSE

OF THE

STUDY

The purpose of this study was to investigate the factors that contributed in shaping preservice science teachers’ mental images at the microscopic level of matter in chemistry.

METHODOLOGY The nature of pre-service science teachers’ mental images in chemistry was investigated using a combined method of interviewing and guided imagining. The following sections describe the method, population and sample, and procedure.

GUIDED IMAGERY INTERVIEWS During guided imagery activities, students create images based on what they hear. These images are influenced greatly by their previous knowledge, and sometimes they are animated objects in 3D formats. If these two assumptions are valid, then a guided imagery activity with a chemistry-based passage at the particulate level should reveal students’ mental microscopic images and their understanding of the interactions among the micro-particles. In addition, it should demonstrate students’ level of scientific imagination. During this study, the guided imagery procedure was conducted individually with each participant and followed by an interview to explore the nature of the students’ mental images during that imagery activity. Using interviews to investigate students’ conceptualization is also called a “thinking aloud procedure” (Bowen, 1994). It provides rich information about students’ processing of information and allows for deeper probing of their responses. For the purpose of this study, the combination of the two techniques: guided imagery and interview was called “guided imagery interviews". This combination allowed for non-traditional exploration inside students’ minds to ‘see’ the formation and processing of images. The participant was describing what they envisioned in their own imagination. They were put in an environment where the right

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answer was not the purpose. Therefore, any anxiety in the finding of the right answer was minimized. This is a modified think-aloud technique that incorporates guided imagery. Interview questions are stated in a way that avoids giving the interviewee any hints that might change their description of their mental images. The interviewer reads a sentence from the guided imagery scenario and then the interviewee is asked to recall the mental images that they had created when they had heard that sentence during the guided imagery session. No new information was supplied to the interviewee. For instance, one question reads: " When I recited (Now, the two hydrogen atoms are bounded to that oxygen atom), what did you see? How did you view this event?” No further information, beyond what is stated in the scenario, is included in the question. What is more, the questions do not ask the interviewee to recall information or recite sentences from the imagery scenario. So, the above question does not read, for example, “What happened to the two hydrogen atoms?” This is done to avoid any anxiety that might be created from the participants’ fear of being unable to remember parts of the imagery scenario. If they were anxious, they might not be able to convey their imagination properly.

POPULATION

AND

SAMPLE

Population The intended population was all preservice science teachers who were studying on a 4-year teacher training B.Ed. program at the College of Education at the Sultan Qaboos University. It included all students who were majoring in science education at that college between the second and fourth years. Sample The sample included 22 preservice science teachers at the Sultan Qaboos University in Oman. The participants’ real names were kept anonymous. The participants were 14 females and eight males. There were ten fourthyear students, six third-year students, and six second-year students. According to their grade point average (GPA), there were seven C-level students, 14 B-level students, and one A-level student. Also, the sample included 17 chemistry majors, and five physics majors.

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INTERVIEW PROCEDURE Twenty-two preservice science teachers at the Sultan Qaboos University were interviewed to examine their mental images while engaging in guided imagery tasks. Each student was interviewed individually in a 40– 60 min session. The interview was composed of two main sections: a guided imagery activity and follow-up questions. The imagery scenario was validated for its scientific accuracy and whether it obeyed the format of guided imagery scenarios. The validation process was conducted by five science educators, three chemists, and two psychologists who are guided imagery specialists. The interview scenario and its questions were validated by the same group of referees. What is more, the three chemists, who work as chemistry professors at a Midwest American university, validated the scenario for the scientific precision of the explanations, and stated that it had no potential for encouraging participants to form new alternative conceptions. The reaction of sodium in water was used as a context for the guided imagery interview. This reaction was chosen for the following reasons: First, it has clear observations: namely the formation of hydrogen gas, the violent movement of the sodium piece, and flame formation. The clarity of the observations was necessary to avoid any possible vague remarks about the results of the phenomenon. Second, the explanation of this phenomenon integrates several microscopic principles in chemistry, such as the formation of chemical bonds, the excitement of electrons to a higher state level and the emission of light and energy. Investigating participants’ mental images of these diverse microscopic components was essential for the purpose of this study. The guided imagery scenario focuses first on the formation of hydrogen gas. Then it describes how hydrogen gas reacts with the oxygen from the air as a prerequisite for flame formation. The scenario could have gone in a different direction by describing the formation of the direct product of the reaction of sodium in water, namely the hydrogen gas and sodium hydroxide. However, this description would be less diverse, with regards to the microscopic principles involved, than the description of flame formation. Therefore, creating mental images for the excitement of electrons to a higher state level and the emission of light and energy gives the interviewer more opportunities to detect the possible associations of movement and colors to the images. To ensure that all participants were familiar with the reaction of sodium in water, each participant was first presented with a 2-min video clip presenting a demonstration of the reaction of sodium in water. During

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the clip, the demonstrator was adding a small piece of sodium to a 1,000ml beaker of water. The reaction was violent and it produced a flame. After showing the reaction to the student, the guided imagery activity was conducted for approximately 5 min. The guided imagery scenario reads: “Close your eyes … Imagine that you are riding a special vehicle that takes you inside the beaker where the reaction of sodium and water takes place. Your goal is to investigate how the flame forms. You are riding that vehicle now. You are heading towards the sodium piece inside the water. You arrive right after dropping the piece into the water. The flame has not formed yet. Hydrogen gas has started to form. From the window of your vehicle you see hydrogen molecules going upwards. Every two atoms that are bonded together go upward towards the surface. You also see two electrons orbiting the two atoms in order to hold them together. What is the fate of these molecules? You decide to ascend upwards by your vehicle to see what is going on in there. You feel that the heat is too high. Molecules are moving very violently. You see that they come out of the surface into the outside air. You decide to monitor one of these molecules. It is heading towards an oxygen molecule. It hits it very strongly. You see that the hydrogen electrons, which are orbiting its two atoms, are disrupted very violently as a result of this collision. Suddenly, they fall into two empty orbits around one of the oxygen atoms. Now, the two hydrogen atoms are bounded to that oxygen atom. At the same time, another hydrogen molecule hits the other oxygen atom and binds to it. Suddenly, the double bond that binds the two oxygen atoms breaks up and each atom goes with two hydrogen atoms to form a water molecule. You feel that the heat rises very rapidly as a result of this molecules formation. It is too hot over here. You feel it in your body. But what do you see? You see the formed water molecules spin very violently and collide with the surrounding molecules. Your vehicle is shaking…and shaking…oooh you fall down on the floor…Stand up quickly … look from the window and what do you see?… You see the movements become unusual in the whole region. Molecules spin and vibrate very violently. As a result, you see the electrons of these molecules are disrupted very greatly and thrown into higher orbitals. Then they fall back to their normal locations. What’s a view! As they fall back to their normal locations, photons of light come out. The region becomes luminous. The process happens several times here and there. Molecules emit photons. The releasing of photons increases. You are now at the middle of the flame. The flame expands. You have to run away. Without any thinking, you turn your vehicle on and go away from that place… Now open your eyes.”

After the imagery activity, the student was asked to talk about everything they imagined during the imagery journey. Some probing questions were asked for more clarification. These questions focused on describing the mental images visualized by the student. The student was then asked to draw a sketch of the vehicle they had imagined during the mental journey, and describe their position according to the beaker where the reaction of sodium and water took place. Next, 14 sentences were chosen from the guided imagery passage and recited again to the student.

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After the recitation of each sentence, the interviewer asked the student to talk about what they had imagined when hearing this particular sentence during the imagery activity. ESM#1 presents the clinical interview protocol, which includes the guided imagery passage that was recited to the students and a sample of the interview questions. The interviews were audio-taped and then transcribed. The major themes that emerged from the interviews were listed and classified into categories.

RESULTS

AND

DISCUSSION

The findings suggested that there were categories of factors that shaped participants mental images at the microscopic level of matter. The first category included factors that related to learners’ past experiences in chemistry. These factors were: textbooks, modeling kits, a solar-system model, the physical world, and cartoons and humanization. The second category dealt with participants’ own abilities such as imaginative ability, attention level, and self-involvement. The last category described the influence of the nature of dynamic interactions at the microscopic level on participants’ mental processing of these interactions. Textbooks The results indicated that textbook illustrations played a big role in shaping participants’ mental images at the particulate level during the guided imagery session. Images in 2D format formed 39.15% of the overall created mental images. Three participants viewed all their images as twodimensional illustrations. Two other participants had all their images as 2D illustrations except for the hydrogen gas. At the beginning they viewed it as bubbles. Then these bubbles transformed into 2D illustrations. Seven participants (31.8%) viewed one micro species or more as the English letters ‘H’, ‘O’ and ‘e’. Also, seven participants viewed one micro species or more as circles, which are the common illustrations of atoms, orbits and electrons in textbooks. One participant stated: Each two H’s were connected together with a string ascending up to the surface. (Zaid, a third-year physics major).

Lewis structures in textbooks use dots to represent the electrons around atoms. Six participants (27.3%) imagined the electrons as dots. Also, textbook illustrations of Lewis structures use arrows to indicate the transfer of electrons from one atom to another. One participant imagined

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the transfer of electrons from hydrogen atoms to the oxygen atom as arrows. He described how: I saw the hydrogen electrons leaving their orbit to the oxygen orbits. I visualized it like an arrow heading from the hydrogen to the oxygen, like Lewis structure illustrations in textbooks. (Edrees, a third-year physics major).

Lewis structures also put the binding electrons as dots between two atoms. Two participants imagined electrons between atoms. In addition, textbooks always describe the electrons as an “electron cloud". Four participants imagined the electrons as a cloud. One participant described it as follows: Then I imagined electrons rotating around the balls. I imagined two balls as nuclei and there was a cloud between these two balls. (…) The cloud was like the normal clouds in the sky. (Zaynab, a fourth-year chemistry major).

Also, textbooks present the levels of energy as lines with arrows pointing up or down, indicating the movement of electrons from lower levels of energy to higher ones and vice versa. Four participants imagined lines as levels of energy during the emitting event. Two participants could not imagine any form of electrons moving up or down. Instead, they imagined arrows. One participant explained: They were like lines and the electrons were going up and down. I didn’t see the electrons as I saw them before. I just saw a single arrow going up and down (Sumayah, a fourthyear physics major).

One participant imagined water molecules in a V-shape, which is the common illustration for these molecules. Another participant imagined the emitting of photons as a laser beam. Some illustrations in textbooks present the bonding of two atoms as two overlapped circles. This type of illustration was imagined by one participant who described her imagination of hydrogen molecules as follows: They (hydrogen atoms) were not connected except for their orbits. There was an overlap between their orbits, like an overlap between two circles (Qabas, a third-year chemistry major).

Lines are the common illustration of bonds between atoms. Two participants viewed two lines connecting the two oxygen atoms. One participant imagined a line connecting the hydrogen atoms. Modeling Kits Modeling kits are frequently used to help students grasp the geometry of molecules. These kits are either balls and sticks or space filling kits.

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Fifteen participants (68.2%) imagined one atom or more as a sphere(s) or ball(s). Images in 3D formats represented 33.36% of the overall created mental images. Four participants created more than 60% of their images in 3D formats. Two participants reasoned that the most common balls used to represent the Oxygen atoms using the modeling kits, are blue balls. Blue was the dominating color for oxygen atoms during the guided imagery session. Six participants out of eight, who imagined oxygen atoms as balls, imagined blue balls for oxygen. Three participants imagined white balls for hydrogen atoms and four imagined red balls for these atoms. This might be also associated with the colors students used for these atoms during the modeling sessions. Eleven (50%) participants imagined water molecules as three connected balls with an oxygen ball at the middle and two hydrogen balls on its right and left sides. This image is most probably influenced by the use of the modeling kits. One participant described how: Then the water molecule formed. It was one big ball, the oxygen, and two small balls, the hydrogen, connected to its sides. There was no space between the balls (Zaynab, a fourthyear chemistry major).

Solar-System Model The solar-system model is frequently used to represent the rotation of electrons around the nucleus of the atom (Harrison & Treagust, 1996). Nine participants (40.9%) imagined circular orbits around the oxygen atoms. Seven of them (31.8%), imagined the oxygen atom as electrons on circular orbits around a ball, circle or English letter ‘O’. This view was very close to the solar-system model. One participant described his imagination as follows: The oxygen ball had too many steel ball-like electrons around it, like 16 or so. They were organized in a spiral orbit. Each electron was rotating in an opposite direction to its neighboring electron (Edrees, a third-year physics major).

Two participants imagined views that were very close to the solarsystem model during the emitting event. One participant described how: Then I saw a group of electrons around a molecule. They were arranged in a ring shape, like Saturn's rings (Safeyah, a fourth-year chemistry major).

Thirteen participants (59%) imagined the hydrogen’s electrons rotating around the hydrogen atoms. One participant imagined electrons rotating around an oxygen atom, and two imagined electrons rotating around

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water molecules. The rotation of an object around another is a distinguishing feature of the solar-system model. One participant imagined the electron rotating around itself. She described how as: Each electron was rotating around itself like the rotation of the Earth around its axis (Qabas, a third-year chemistry major).

Harrison and Treagust (1996) found that this model is the most preferred model used by students to represent the atom. The Physical World Sometimes, during the guided imagery session, the participant could not imagine a micro event or a micro species as a single entity. Instead, they imagined a phenomenon from the physical world. Ten participants (45.5%) imagined the rotation of the water molecule around itself as cyclones in liquid water. They could not imagine water as molecules or small units as did the other 11 participants. Also, during the emitting event, only four participants (18.2%) imagined photons as small units of light. The rest imagined them as beams of light, comets, falling stars, flames, a big light, or fireworks. Three participants imagined the returning of electrons from a higher level of energy to a lower one as comets or falling stars. One participant explained that the heads of the comets were the electrons. Their imagination might combine the return of small units (electrons) and the formation of the flame and sparks to form an image of falling stars or comets. There was another type of physical world association attached to the elements of the particulate level. It was when the participant used a smaller unit of the physical world elements to represent a species of the particulate level. Thirteen participants (62%) imagined atoms or molecules as bubbles, and one participant imagined the hydrogen as steam escaping from the water surface. Also, four participants (18.2%) imagined the photons as sparks. One participant imagined water molecules as drops of water rotating together, and another imagined the falling of the hydrogen’s electrons as drops of water dropping into an orbit around the oxygen atom. The words in the guided imagery scenario might play a major role in shaping these images. Twelve of the bubble images were for the hydrogen gas. Since gases are seen in chemistry labs as bubbles, the world “gas” triggered the image of bubbles and similarly, for the drops of water case. Drops of water are the smallest units of water that can be seen with the naked eye. The participants substituted the word “water molecules". The last case was related to the photons. Participants, before the beginning of the guided imagery session, watched a video clip about the reaction of

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sodium in water, which produced sparks and then flames. The sparks appeared in their imaginations during the photons emitting event. There were incidences when participants’ images of the particulate level combined both micro and macro elements. The participants in these cases could not avoid the association of the physical world in their images. For instance, two participants imagined the water molecules’ rotations as a single molecule, which was rotating in the liquid water and causing a cyclonic movement. Another participant imagined several water molecules moving randomly and cyclones started to form in the liquid water. The presence of both water molecules and liquid water in these images suggested the difficulty that students face in conceptualizing the particulate entities of a medium (water in this case) without having the same medium as a connection between these entities. The molecules were the water molecules, yet the liquid water was present around these molecules. The molecules of a fluid were imagined as objects inside that fluid. This was similar to the previous research findings that revealed that students believed that the space between gas molecules was filled with air, and the space between water molecules was filled with water (Nakhleh & Samarapunga van, 1999; Osborne & Freyberg, 1985). Liu and Treagust (2005) argue that the mental state must be systematically connected with the physically observable elements and external reactions that allow the mental states to act in the role of explaining behavior and cognition. Cartoons and Humanization Eight participants (36.4%) had images that looked like cartoon characters: humanization. For three of them, these images appeared for one time only. Another three sometimes viewed the atoms and molecules as cartoon creatures and at other times as balls or circles. The last two of these eight participants viewed all the images as cartoon or humanized beings. One participant stated: They [hydrogen’s electrons] had two hands, too. Then the oxygen appeared. It was like a smiling face also with hands, eyes, and mouth. It was bigger than the hydrogen. The hydrogen hit the oxygen, but both were laughing. The electrons were circling the hydrogen. They appeared to be disturbed. They were like not knowing where to go. They were wandering (Sumayah, a forth-year physics major).

There were three possible factors for such humanized images. The first reason was that there was a cartoon program that was broadcast on the national TV channel several times. This program was about the human body. Its characters were the brain, different blood cells, oxygen atoms and molecules, microbes, and many other things. These characters had humanized characteristics: faces, hands, legs, etc… The main purpose of

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this program was to explain the biological processes that took place in the human body such as the circulation of oxygen, the role of the immune system to fight the microbes, and the digestion process. The characters appeared to talk and behave as humans. Two participants mentioned that their images were greatly influenced by this program. The second reason was the study practice used by participants. Two participants explained that they preferred to imagine such creatures when they study. They reasoned that it became easier to grasp scientific processes in the human body or chemical reactions when they used such a strategy. The third reason was the style guided imagery scenario used in this study. Moreover, the scenario did not use any humanized or anthropomorphic expressions. The narration was like a story style, which might impose a feeling that the particles were like characters in a play. One participant explained: If you cannot create things in your mind, the cartoon helps you by presenting unusual things that do not exist in reality. Most of the cartoon is impossible; animals talk, electrons talk, and atoms talk. It helps you imagine things (Sarah, a fourth-year chemistry major).

Attention and Self Involvement One of the important factors that influenced participants’ mental images was the attention level paid by each of them during the guided imagery activity. Learners are different in their level of attention during information processing (White, 1988). It was not the purpose of this study to measure this level. Nevertheless, there were signs of the attempts initiated by the participants to pay full attention during the activity. Besides the attempts by the participants to create mental images of what they were hearing during the activity, their attention produced images that were beyond the imagery scenario. There were instances when participants imagined interactions beyond what was in the guided imagery scenario. Four participants’ (18.2%) imagination of the disturbance of hydrogen’s electrons after it collided with the oxygen was not mere shaking or faster movement or rotation. Also, four participants’ (18.2%) visualization of the transfer of hydrogen’s electrons to the oxygen was not mere moving or dropping transfer. All the participants who had such imaginings were female chemistry students. Examples are: Then the two electrons around the hydrogen started to move away from the hydrogen. One moved up right and the other moved down left (Asma, a fourth-year chemistry major). The collision between the hydrogen and the oxygen made the hydrogen electrons move violently. They were trying to escape from their orbit (Qabas, a third-year chemistry major).

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Some other participants imagined themselves interacting with some elements of their imagination. They were “running away” from molecules, or “avoiding” cyclones. One participant imagined the orbits above her arranged in a cone-like shape. Then the emitting event happened just above her. Some other participants imagined themselves “stifled", or “annoyed” by the heat. None of these behaviors or interactions was mentioned in the guided imagery scenario. These examples and others illustrate the attention paid by the participants during the imagery activity. It might be their deep conscious attention that allowed for their tacit knowledge to constitute their images unconsciously. One participant did not feel the heat but he imagined it as waves heading towards his ship. He explained that: I didn’t feel the heat of the reaction but I was seeing it as reddish circular waves heading towards my ship. These waves didn’t affect me or my ship in any way (Zaid, a third-year physics major).

Even if the guided imagery scenario did not mention any type of sound, seven participants (31.8%) reported they heard sounds. Five of them heard sounds during the collision of the hydrogen and oxygen. Two of them heard the sound of their ships while they were running. One participant described how: Then we went up and the hydrogen balls hit a blue oxygen ball. I heard a sound like a book dropping on the floor. That sound was from the collision (Ameena, a fourth-year chemistry major).

Also, the guided imagery scenario did not mention any type of smell or taste. Yet, two participants (9%) stated that they smelled something. One participant described: I also smelled the hydrogen as ammonia gas. It was like something entering my nose. The smell was a strong gas odor (Safeyah, a fourth-year chemistry major)

Three participants (13.6%) stated that they tasted something. One participant described: At this moment I tasted water on my tongue (Ali, a fourth-year chemistry major).

Imaginative Ability People are not equal in their imaginative ability. This fact was reflected in the participants in this study. Some participants managed to create mental

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images for the electrons and the photons, yet others could not, however hard they tried. Some participants created 3D images, while others imagined 2D illustrations and some others imagined black letters. Imagination of colors varied too. In some participants’ imagination of the micro particles, they were colored while others’ were black. Others could not distinguish any color. Some participants somehow heard sounds, tasted water, or smelled gases. Others did not experience these things. The difficulty in creating images for different dynamic interactions is another example of how individuals’ imaginative ability plays a role in determining the nature of their mental images. This is discussed more extensively in the next section. There were other examples that might be attributed to learners’ limited imaginative ability. Five participants (22.7%) did not see the electrons doing the disturbing. Instead, they imagined larger particulate species such as atoms make a disturbance. Two participants (9.5%) imagined atoms or molecules doing the “going up and coming back” behavior of the electrons during the emitting event. Dynamic Interactions The imagination of dynamic interactions differed from one participant to another. Almost one-third of the sample could not create an image for the disturbance of hydrogen’s electrons after the collision with the oxygen. One-third also could not create an image for the transfer of electrons from the hydrogen to the oxygen. Two-thirds of the sample did not manage to form an image for the rotation of a single water molecule. On the other hand, more than 80% of the sample managed to create an image of the transfer of electrons during the photons emitting event. From these statistics, the hardest event to imagine was the rotation of a single water molecule. The first reason that might contribute to this difficulty was their previous experiences. This event is rarely mentioned in Omani national science textbooks at the secondary and university levels. On the other hand, the electrons transfer event and their transfer during the emitting event is repeatedly illustrated in the chemistry textbooks throughout the secondary and university levels. The disturbance of electrons event was the third easiest event to imagine. Even though it is rarely mentioned in student texts, it is mentioned in the guided imagery scenario. Also there is a similar event that is frequently discussed in physics texts in both secondary and university levels. It is the disturbance of molecules in different states when they are heated up. The types of movements in the transfer, emitting, and disturbance events are very similar. They are right-left or up-down types of

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movement. Therefore, the rotation movement becomes different in nature. This difference might contribute to the difficulty in imagining a single water molecule rotation. The third reason for this difficulty might be the fact that the word “water” is always associated in daily life with liquid water. This might be why more than 38% of the sample imagined cyclones in the water surface (macroscopic) instead of a microscopic movement. Finally, moving from one sentence to the next during the imagery activity required adding new objects to the existing number of objects in a presently constructed image. Maintaining a rotational movement for the electrons and then adding other objects to the created image seemed to overload the working memory. It might be plausible to say that the number of objects exceeded the maximum number of chunks permitted by each participant’s information processing ability (Lawson, 2004, White, 1988).

CONCLUSIONS Participants in this study lacked the homogeneous and reliable mental model of the atom that was required to carry out advanced cognitive processes for mental exploration of chemical phenomena. This might explain the repeated findings in the literature that students do not go beyond arithmetic manipulations. Their understanding of the chemical principles behind equations and formulas is absent (Gabel et al., 1984). Past research in chemistry education reveals that the comprehension of chemistry phenomena is a prerequisite to an ability to visualize the particulate and kinetic nature of matter (Day, 2004; Harrison & Treagust, 1996; Vos & Verdonk, 1996). This study supports the findings of earlier research. Participants’ mental images at the microscopic level of matter consisted of observations that might support the notion that their mental models of the atom did not reach the degree of homogeneity and reliability that allowed them to explain chemical phenomena at the microscopic level. The observations were: 1. Three-Dimensional Images: Three-dimensional mental images represented 33.36% of participants’ mental images at the microscopic level. Using 3D representations in teaching chemistry has proven superior to using 2D representations in retention tests, long-term cumulative effects on students’ understanding, and problem solving (Rudmann, 2002; Wu, Krajcik & Soloway, 2000). The spatial visualization stimulated by 3D representations provides a concrete

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experience of entities that are easily rotated, created, and modified (Wu, Krajcik & Soloway, 2000). This accelerates and improves the manipulations process of these micro-entities and consequently expedites the explanation and prediction of the phenomenon under study. Two-dimensional representations appear in students’ texts, instructors’ blackboards, worksheets, overheard transparencies, and PowerPoint slides. For some participants in this study, and others among chemistry students, 3D representations are absent. The only courses that some participants in this study took that provided them with 3D modeling kits were the Introduction to Organic Chemistry and Organic Chemistry. These are given to chemistry majors only. Physics and biology majors do not enroll in any course that provides them with such kits. This might explain why 2D representations dominated participants’ imaginations. 2. Modeling Kits: A space-filling 3D mental model was more prevalent than the balls-and-sticks. This is consistent with the findings of Harrison & Treagust (1996). In their study, students chose a space-filling model to represent a molecule. However, Wu et al. (2000) argue that ball-and-stick mental models are more practical in problem solving. These models demonstrate the spatial geometry of atoms and the bond orders necessary for identifying functional groups and picturing transforming from one type of representation to another. 3. Lewis structures: Lewis structure illustrations in textbooks usually place the shared electrons in the space between the two involved atoms. This image might have played a significant role in restricting the motion of the electrons and mentally forces participants to stay stuck in that position. Those who viewed the electrons located between the two atoms of hydrogen, either could not create a rotational movement for the electrons around hydrogen atoms, or they imagined them rotating in the space between the atoms. Both images might reveal how the Lewis structure contributed in restricting participants’ dynamic imagination. 4. Solar-System Dynamics: Harrison & Treagust (1996) explain that the solar-system model over-simplifies the atomic model by demonstrating a distorted image of the atom. Using this model to mentally process dynamic interactions among micro-species yields inaccurate conclusions. Nevertheless, because of the simplicity of the solar-system model, it is more plausible to learners of chemistry than more

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complicated models. Dynamic interactions become easier to process. For instance, the electron cloud model, presented in the Harrison and Treagust study as having more scientific accuracy than the solarsystem model, has no pictures of electrons. The electrons cannot be located. Therefore, imagining electrons in dynamic interactions violates the basic assumptions of the electron cloud model. The four participants in this study who imagined an electron cloud, could not resist having electrons in their images. In addition, the learner might believe in the electron cloud model, as did a few students in Harrison and Treagust’s study. Yet, the intensity of past experiences shapes the existing mental model in the learner’s mind. The solar-system model is presented overwhelmingly in all instructional materials in chemistry. It might be plausible to say that its intensity becomes mentally denser and forms more connections than the electron cloud model experience. Apparently, participants in this study, and in most chemistry teaching practice, lack the opportunity to train their minds to construct images that imitate the electron cloud model. 5. Arrows Dynamics: Besides indicating the text’s influence on participant’s mental images, imagining arrows also reveals a difficulty in imagining dynamic interactions, especially fine details such as electron transfer. Arrows do not help to recognize the causes of the interactions, such as the force behind the transfer of electrons. Arrows show movement from internal, rather than external causes, yet it is the external attraction and repletion force that controls the movement of electrons. 6. Humanized Dynamics: Humanizing micro particles constructs a false picture of the real cause of their interactions. When an “electron [is] running after another on that orbit,” the initiator of the movement is the electron itself, not the attraction between it and the positive charge of the atom. Furthermore, the details of the faces and limbs might create undesirable interference with the attention needing to be given by the participant. Consequently, they may not pay a sufficient level of attention to processing the dynamic interactions among the microspecies. 7. Physical World Dynamics: Both imagining cyclones instead of molecules, and imagining H2O (as letters) rotating in liquid water create a distorted image that does not obey the fundamental teaching of the particulate theory of matter. The first image represents a clear difficulty in imagining water as molecules. The second image represents a common misconception among students in chemistry, that matter is continuous (Dori & Hameiri, 2003; Nakhleh &

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Samarapungavan, 1999; Osborne & Freyberg, 1985). Since both images do not represent an accurate picture of the particulate nature of matter, they are not expected to produce an accurate dynamic picture of the interactions at the particulate level of matter. 8. Unstable Mental Model: Most of the participants experienced image transformation from one form to another as they were progressing in the GI session. For one participant, Khawlah, hydrogen and oxygen atoms underwent a back-and-forth transformation from 3D format to humanized format. This unstable reliance on different models might indicate unorganized conceptual networks in learners’ LTM: a feature that characterizes novices’ mental networking (White, 1988). On the contrary, research has revealed that experts have more organized and sophisticated conceptual networking. Therefore, the interference to their mental images while thinking should be minimized. Their mental processing is based on one steady and well-organized model.

RECOMMENDATIONS It has been argued that participants in this study lacked a homogeneous and reliable mental model of the atom, which is the core requirement for advanced thinking to explain and predict chemical phenomena. The absence of this mental model might explain the overwhelming finding in literature that many learners fail to carry out these two processes. In order to enhance their students’ visualization at the microscopic level of matter, K-12 science teachers need to design pedagogical activities such as guided imagery sessions, modeling molecules with clay or magnets, 2D representations, and computerized animations. Further research might compare learners’ mental images in different cultures and investigate the social impact on their imagination in science. REFERENCES Apollonia, S. T., Chales, E. S., & Boyd, G. M. (2004). Acquisition of complex systemic thinking: Mental models of evolution. Educational Research and Evaluation, 10(4–6), 499–521. Black, A. A. (2005). Spatial ability and earth science conceptual understanding. Journal of Geosciences Education, 53(4), 402–414. Bowen, C. W. (1994). Think-aloud methods in chemistry education: Understanding student thinking. Journal of Chemical Education, 71(3), 184–190.

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Coleman, S. L., & Gotch, A. J. (1998). Spatial perception skills of chemistry students. Journal of Chemical Education, 75(2), 206–209. Connolly, B. A. (1994). An experiment in mnemonics imagery in adult basic education science instruction. Retrieved October 7, 2008, from ProQuest Database, (AAT MM95855). Czolpinski, A., & Babul, A. (2005). The art of physics: Visualizing the universe, seeing the unseen. Pi in the Sky, 9, 4–8 December. Day, R. (2004). Visual cognition in understanding biology labs; can it be connected to conceptual change? A paper presented at the National Association of Research in Science Teaching Conference, Vancouver, Canada. Dori, Y. J., & Hameiri, M. (2003). Multidimensional analysis system for quantitative chemistry problems: Symbol, macro, micro, and process aspects. Journal of Research in Science Teaching, 40(3), 276–302. Gabel, D. L., Sherwood, R., & Enochs, L. (1984). Problem-solving skills of high school chemistry students. Journal of Research in Science Teaching, 21(2), 221–233. Gooding, D. C. (2004). Envisioning explanations- the art in science. Interdisciplinary Science Reviews, 29(3), 279–294. Hadzigeorgiou, Y., & Stefanich, G. (2000). Imagination in science education. Contemporary Education, 71(4), 23–29. Harrison, A. G., & Treagust, D. F. (1996). Secondary students’ mental models of atoms and molecules: Implications for teaching chemistry. Science Education, 80(5), 509–534. Hegarty, M. (2004). Mechanical reasoning by mental simulation. TRENDS in Cognitive Sciences, 8(6), 280–285. Hmelo-Silver, C. E., & Pfeffer, M. G. (2004). Comparing expert and novice understanding of a complex system from the perspective of structures, behaviors, and functions. Cognitive Science, 28(2004), 127–138. Kozhevnikov, M., Motes, M. A., & Hegarty, M. (2007). Spatial visualization in physics problem solving. Cognitive Science, 31, 549–579. Lawson, R. E. (2004). The nature and development of scientific reasoning: A synthetic view. International Journal of Science and Mathematics Education, 2, 307–338. Liu, C., & Treagust, D. F. (2005). An instrument for assessing students’ mental state and learning environment in science education. International Journal of Science and Mathematics Education, 3, 625–637. Lord, T. R. (1990). Enhancing learning in the life sciences through spatial perception. Innovative Higher Education, 15(1), 5–16. Mathewson, J. H. (1999). Visual-spatial thinking: An aspect of science overlooked by educators. Science Education, 83, 33–54. Nakhleh, M. B., & Samarapungavan, A. (1999). Elementary school children’s beliefs about matter. Journal of Research in Science Teaching, 36(7), 777–805. Naveh, D. (1985). Holistic education in action: An exploration of guided imagery in a middle grade science class and its impact on students. Dissertation Abstracts International, (DAI 8526358). Nemotko, A. (1990). The learning effects of verbally and pictorially presented biology lectures on female college students of high imagery and low imagery abilities. Dissertation Abstracts International, (DAI-A 51/05). Osborne, R., & Freyberg, P. (1985). Learning in Science: The implications of children’s science. Hong Kong: Heinemann.

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Ozmen, H., Demircioglu, G. & Coll, R. (2007). A Comparative study of the effects of a concept mapping enhanced laboratory experience on Turkish high school students’ understanding of acid-base chemistry. International Journal of Science and Mathematics Education. Retrieved March 15, 2008, from http://www.springerlink.com/content/ x65h373125r306w0/fulltext.pdf Pribyl, J. R., & Bodner, G. M. (1987). Spatial ability and its role in organic chemistry: A study of four organic courses. Journal of Research in Science Teaching, 24, 229–240. Reiner, M., & Gilbert, J. (2000). Epistemological resources for thought experimentation in science teaching. International Journal of Science Education, 22(5), 489–506. Rudmann, D. S. (2002). Solving Astronomy Problems Can Be Limited by Intuited Knowledge, Spatial Ability, or Both. (ERIC Document Reproduction Service No. ED468815) Shepard, R. (1988). The imagination of the scientist. In K. Egan, & D. Nadaner (Eds.), Imagination and education. New York, NY: Teachers College Press. Stephens, L. & Clement, J. (2006). Using expert heuristics for the design of imagery-rich mental simulations for the science class. Proceedings of the NARST 2006 Annual Meeting, San Francisco, CA. Taylor, N., & Coll, R. K. (2002). Pre-service primary teachers’ models of kinetic theory: An examination of three different cultural groups. Chemistry Education: Research and Practice in Europe, 3(3), 293–315. Valanides, N., & Angeli, C. (2006). Preparing preservice elementary teachers to teach science through computer models. Contemporary Issues in Technology and Teacher Education, 6(1), 87–98. Van Driel, J. H., & De Jong, O. (2002). The development of preservice chemistry teachers’ pedagogical content knowledge. Science Education, 86, 572–590. Vos, W., & Verdonk, A. H. (1996). The particulate nature of matter in science education and in science. Journal of Research in Science Teaching, 33(6), 657–664. White, R. T. (1988). Learning science. New York, NY: Basil Blackwell Inc. Wu, H., Krajcik, J. S. & Soloway, E. (2000). Promoting Conceptual Understanding of Chemical Representations: Students’ Use of a Visualization Tool in the Classroom. (ERIC Document Reproduction Service No. ED 443678) Yang, E., Andre, T., Greenbowe, T. J., & Tibell, L. (2003). Spatial ability and the impact of visualization/animation on learning electrochemistry. International Journal of Science Education, 25(3), 329–349. Curriculum and Instruction Department, College of Education Sultan Qaboos University PO Box 32, SQU 123 Muscat, Oman E-mail: [email protected]