BACKGROUND, FRAMEWORK, AND PURPOSE

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1 RAISING THE LEVEL OF UNDERSTANDING THROUGH THE USE OF DYNAMICALLY LINKED CONCRETE AND ABSTRACT REPRESENTATIONS IN VIRTUAL LABORATORY ENVIRONMENTS IN ELECTRIC CIRCUITS Athanasios Taramopoulos and Dimitrios Psillos Department of Primary Education, Aristotle University of Thessaloniki, Thessaloniki, Greece Abstract: The purpose of this study is to evaluate the effect of investigative activities in virtual laboratory environments which combine concrete and abstract representations to the ability of students to comprehend simple and complex phenomena in the field of electric circuits. An inquiry-based teaching intervention was applied to years old high school students. Thirty six students took part and were assigned to two conditions: 18 had access to a virtual laboratory environment with functional dynamically linked concrete and abstract representations of objects based on the relevant scientific model (AR approach) and 18 had access to the same virtual laboratory environment restricted only to functional concrete representations of objects (CR approach). Apart from this difference, both conditions used the same instructional method and materials. A pre-post instructional assessment scheme was used to evaluate the students conceptual evolution utilizing the Electric Circuits Understanding Tool (ECUT). The questions of the Tool were divided into two subgroups based on the complexity of the phenomena involved: questions regarding low level complexity phenomena and questions regarding high level complexity phenomena. An ANCOVA analysis of the results of the two approaches indicates that after instruction both groups show a similar improvement in comprehending simple phenomena in electric circuits. However, with regard to complex phenomena, the AR approach which used the virtual laboratory with both functional concrete and abstract representations of objects outperforms the CR approach which was restricted to the use of concrete representations of objects. From these findings we conjecture that in the field of electric circuits virtual environments utilizing dynamically linked concrete and abstract representations of objects may provide the necessary scaffolds for students to raise their level of understanding of phenomena with high degree of complexity. Keywords: conceptual understanding, electric circuits, virtual laboratories BACKGROUND, FRAMEWORK, AND PURPOSE A large number of research studies have shown that virtual laboratories, as educational environments utilized in teaching science by inquiry, are not inferior to their real counterparts with regard to conceptual understanding (Ruten et al., 2012). In a number of cases results indicate that the use of virtual laboratories may even outperform real laboratories when used in investigative activities (Finkelstein et al., 2005; Zacharia, 2007). One of the key features of virtual laboratory environments which real laboratories lack is the capacity to afford multiple representations to present the simulated phenomena and the related scientific models. The design features and the role of specific affordances of virtual laboratories in enhancing scientific understanding is under investigation (Mueller & Strohmeier, 2011). One open issue relates to the net effect of the fidelity of the representation to the effectiveness of teaching (Couture, 2004; Imhof et al., 2011) and whether both concrete and abstract representations of

2 concrete objects should be used in teaching conceptually rich topics, or their use increases the students cognitive load and may even inhibit learning (Ainsworth, 2006). Our aim here is to study whether the engagement of students in investigative activities with a virtual laboratory environment, which presents electric circuits with dynamically linked concrete and abstract representations of concrete objects fully functional based on the relevant scientific model, can result in an enhanced understanding of simple and complex phenomena when compared to performing the same teaching intervention using the same virtual laboratory learning environment but being restricted to utilizing only concrete representations. RATIONALE In a virtual laboratory environment such as an electric circuit virtual laboratory, the virtual object representation can vary from a concrete representation with highly realistic virtual instruments to an abstract representation such as a schematic drawing of a circuit. The impact of the concreteness of the representation on the students conceptual evolution gain is still an open issue. A study of the effectiveness of the various representations might contribute significantly to understanding the differences reported in the results of various research studies concerning the effectiveness of virtual laboratories as an educational tool in science education. Our approach draws on teaching science as inquiry (McDermott & Shaffer, 2002; Sadeh & Zion, 2009) involving students in guided experimental activities utilizing an open virtual laboratory environment with the capacity to provide dynamically linked abstract and concrete representations of objects. While carrying out the experimental activities, the students may be restricted to using only concrete representations, or be prompted to frequently switch between dynamically linked concrete and abstract representations. It is hypothesized by the present study that the students who use dynamically linked concrete and abstract representations when prompted to frequently switch between the two representations will benefit more and outperform the rest of the students who use only concrete representations. METHOD Instruction made use of the 3-dimensional virtual reality electric circuit laboratory of the Open Learning and Laboratory Environment (OLLE). OLLE is an open learning environment that supports doing science by open experimentation and investigation (Psillos et al. 2008). It is a multi-faceted virtual laboratory in the fields of Optics and Electricity developed in the Greek language. As its name suggests, it is an open virtual laboratory environment in which users construct the setup of their choice with fully and continuously functional virtual instruments. Apart from the 3-dimensional virtual reality laboratory with navigation and rotation capabilities, zoom etc., OLLE provides its users with an additional space in the virtual lab, the model-space, which depicts a 2-dimensional symbolic representation of the real laboratory setup. In the electric circuits laboratory, model-space displays in real time the schematics of the circuit constructed by the user (Figure 1).

3 Figure 1. The virtual laboratory of electric circuits with concrete and abstract (schematic) representation of the circuit elements The teaching intervention took place in a high school in Greece with a sample consisting of 36 students, years old. The students were randomly assigned to two approaches: 18 had access to a virtual laboratory environment with functional dynamically linked concrete and abstract representations of objects based on the relevant scientific model as shown in Figure 1 (AR approach) and 18 had access to the same virtual laboratory environment restricted only to concrete representations of objects like the objects on the bench shown in Figure 1 (CR approach). Both approaches used the same instructional method (teaching-by-inquiry) and material. Students had previously some familiarization in performing hands on and virtual experiments in introductory electricity with OLLE. Instruction involved seven units. The first unit dealt with Ohm s law, the second and third units dealt with Kirchhoff s two laws, while the fourth and the fifth unit studied the total resistance of resistors connected in series and in parallel. The last two units dealt with the heat produced by a resistor and the energy given to a circuit by a battery and spent by the elements of the circuit. The students worked in pairs and carried out all investigative activities guided by appropriately structured printed worksheets, which followed the Predict-Observe-Explain scheme (White & Gunstone, 1992). In the beginning the worksheets described an authentic everyday situation and asked the students to predict the outcome of a certain action. Then it instructed the students to perform an experiment in order to test their prediction and described the appropriate steps: discern the quantities which are relevant to their experiment, decide on the circuit elements to use and their values (resistances etc), draw he schematics of the circuit to be constructed, add measuring instruments in the circuit, explain the experimental procedure to be followed, construct the appropriate virtual circuit, check the correctness by carefully inspecting the schematics of the circuit drawn and the circuit constructed, perform the virtual experiment, record the outcome, analyze the results, find the answer to the initial problem and reflect upon their initial prediction. So, after stating their initial prediction, students were instructed to design and carry out relevant experiments to test their prediction, record the results, state their conclusions and compare them to their initial thoughts. Thus,

4 through the worksheets the students were guided to design a proper circuit and an experimental procedure to answer the initial question, rather than being given explicitly the circuit to use and the experimental procedure to follow. Also, in the end the students are guided to discover themselves the appropriate laws from the results of their virtual experiments instead of being given the proper mathematical relations for verification. Special provision was taken to direct students of the AR approach to frequently interact with the model-space tool of OLLE. Throughout all this time the instructor was discretely observing their progress and helping them whenever needed. Instruction can thus be classified as guided inquiry according to the definition of the various types of inquiry of the U.S.A. National Research Council (National Research Council, 2000). A pre-post test design was applied. The test was adopted from the Electric Circuits Understanding Tool (ECUT) developed and tried out with several samples in Greece (Keramidas & Psillos, 2004). It includes 30 items about various electric circuits with four True or False statements at each one (Figure 2). At each item the number of correct statements could vary from 0 to 4. The statements were based on possible alternative or true explanations and were independent of each other. The questions are testing the students conceptual understanding of the operation of electric circuits. They contain questions on the principles needed to construct an operational closed circuit, the laws governing the intensities of the currents flowing through the circuit elements, the voltages of these elements, the resistance of elements connected in series or in parallel and the energy used by bulbs which is shown through their brightness. Figure 2. Example of simple questions The complexity of the items of the test were rated independently by two Science Education researchers and seventeen (17) were categorized as simple items (subtest Gs) and thirteen (13) as complex ones (subtest Gc). Following Olympiou, Zacharia & de Jong (2012) we relate complexity to the number of concepts (abstract or concrete) that a student should consider when mentally constructing the underlying mechanism of a phenomenon. Therefore an electric circuit with few elements is less complex than another one with more elements (the number of concepts increases as the number of the elements to be considered increases). Similarly, an electric circuit phenomenon involving only the intensity of the current through a bulb (resistor) is less complex than a phenomenon involving the light produced by the same bulb. In the examples shown in Figures 2 and 3, questions which involve up to only two bulbs and the current through them are considered as simple ones (Figure 2) and questions which

5 involve three bulbs or more and their current and voltages are considered complex ones (Figure 3). Figure 3. Example of complex questions A student received two separate scores for each subtest scoring 0.25 points for each correctly marked True or False statement. The final score of a student for each of the subtests is the total number of points scored in the subtest adjusted to a 100-point scale. Independent samples t-tests were performed comparing the pre-test scores of the two approaches for both Gs and Gc subtests in order to determine whether the two approaches were comparable with regard to the students initial understanding. The pre- and post-test scores of each approach for both Gs and Gc were compared using paired samples t-tests in order to investigate the effect of the teaching-by-inquiry intervention on the students conceptual evolution. Finally, the post-test scores of the two approaches were compared with each other for both Gs and Gc using one-way ANCOVA to test for any differences. In the ANCOVA analysis the approach was used as a between-subjects factor and the students pretest scores were used as covariates. RESULTS Initially for the simple items the students in both groups had similar mean scores (29,74 and 28,10 for CR and AR approach respectively) and similar standard deviations (10,57 and 8,44 for CR and AR approach respectively), showing that a former domain knowledge existed, which was capable of supporting students in tackling simple problems with limited success. For the complex items both groups showed initially significantly lower scores (5,56 and 5,13 for CR and AR approach respectively) with similar standard deviations (5,07 and 4,79 for CR and AR approach respectively) showing that the pre-existing field knowledge was inadequate to support students in complex situations. After the intervention, for the simple items both groups show a significant and similar improvement with final mean scores of 80,72 and 83,33 and standard deviations of 8,13 and 6,80 for the CR and AR approach respectively. For the complex items however, the final mean scores of the CR approach are significantly lower than those of the AR approach (60,26 and 81,62 for CR and AR approach respectively) with similar standard deviations (9,03 and 7,65 for CR and AR approach respectively). The independent samples t-tests showed that for both the simple and the complex items the two approaches did not differ with respect to their pre-test scores (p simple =0.632>0.05, p complex =0.805>0.05). The paired samples t-tests indicated an

6 improvement in student understanding for both approaches for both simple and complex items (p<0.001 for all comparisons). For the simple items the ANCOVA analysis showed no effect of approach (p=0.453>0.05), no effect of the pre-test scores (p=0.342>0.05) and no effect of the interaction (p=0.764>0.05). For the complex items the ANCOVA analysis revealed a main effect of approach (p<0.001), no effect of the students pre-test scores (p=0.069>0.05) and no effect of the interaction (p=0.381>0.05). DISCUSSION, CONCLUSIONS AND IMPLICATIONS Our findings indicate that virtual environments when used in investigative activities may be effective in supporting students conceptual evolution gains when students are faced with both simple and complex phenomena in electric circuits. All students in both approaches benefited significantly from the teaching intervention and showed great field knowledge improvements. This is in accord with previous research studies on the effectiveness of virtual laboratories as educational environments in teaching electric circuits by inquiry (Taramopoulos et al., 2011). In simple phenomena, such as studying the intensity of the current in circuits with a battery and up to two more elements, concrete representations of objects in the virtual laboratory seem to suffice for supporting conceptual improvement. However, the picture changes when complex phenomena are studied, such as the intensity of the current in circuits with a battery and more than two other elements, or the brightness and voltage of bulbs. Here, the presence of both concrete and abstract representations of objects functioning based on the related scientific model seems to raise the students comprehension beyond what is achieved by the presence of concrete representations of objects alone. One explanation could be attributed to the fact that the simultaneous presence of functional interconnected concrete and abstract representations of objects may help students develop the ability to create stronger links between representations of the required knowledge and to use effectively the most suitable representation whenever needed. This may result in the construction of a higher quality mental model by the student and thus facilitate a deeper understanding of the domain of electric circuits. Our findings are in line with literature studies which show that students show increased problem-solving ability when teaching utilizes both realistic and abstract representations of electric circuits (Moreno et al., 2011), or use both concrete and abstract objects in optics (Olympiou et al., 2012). Clearly, further research is required to ascertain whether virtual learning environments presenting physical phenomena with objects with concrete and dynamically linked abstract representations may be effective tools for facilitating deeper understanding of physical phenomena, as has been found to be the case with electric circuits in the present study. REFERENCES Ainsworth, S. (2006). DeFT: a conceptual framework for considering learning with multiple representations. Learning and Instruction, 16, Couture, M. (2004). Realism in the design process and credibility of a simulation-based virtual laboratory. Journal of Computer Assisted Learning, 20,

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