Asia-Pacific Forum on Science Learning and Teaching, Volume 15, Issue 2, Article 2 (Dec., 2014)
The use of visualization in science teaching
Although visualization has proven to be effective in learning (e.g. Phillips, Macnab, & Norris, 2010), it is necessary to point to the limitations of using visualization for teachers. The following aspects are seen as important to be aware of when using visualization in science teaching and learning.
- Students’ representational competence
The interpretation of visualizations is highly related to prior knowledge in the domain as well as familiarity with, complexity of, and symbolism used in the visualization (Tibell & Rundgren, 2010). To make students move freely between Johnstone’s three representation levels (macroscopic, sub-microscopic and symbolic) is a challenge, particularly for the novices. Kozma (2003) revealed that experienced chemists could move freely between different representations of a phenomenon, but among students, the interpretations were constrained by superficial features shown in the representations. Therefore, developing students’ representational competence is needed, esp. in science education. Through the visualization environment, the representational competence could be developed (e.g. Stieff, 2011). Kozma and Russell (1997) have identified the following skills in the experts’ performance as constituting representational competence in chemistry.
‘‘ (1)The ability to identify and analyze features of a particular representation (such as a peak on a coordinate graph) and patterns of features (such as the shape of a line in a graph) and use them as evidence to support claims or to explain, draw inferences, and make predictions about relationships among chemical phenomena or concepts. (2) The ability to transform one representation into another, to map features of one onto those of another, and to explain the relationship (such as mapping a peak on a graph with the end point of a reaction in a video and a maximum concentration in a molecular-level animation). (3) The ability to generate or select an appropriate representation or set of representations to explain or warrant claims about relationships among chemical phenomena or concepts. (4) The ability to explain why a particular representation or set of representations is more appropriate for a particular purpose than alternative representations. (5) The ability to describe how different representations might say the same thing in different ways and how one representation might say something that cannot be said with another (Kozma and Russell, 1997, p.964).’’
- The choice of visualization
Research has shown that different types of visualization in science can be used for difference purposes (Vavra et al., 2011), the way schematic diagram (i.e. electrical circuit diagram) can illustrate relationships, assist in calculations or provide description of a phenomenon or process. Moreover, animations are able to provide more detailed and accurate representations by showing the movements (e.g. Jones et al., 2005; Rundgren et al., 2012; Sanger & Greenbowe, 1997; Williamson & Abraham, 1995). Teachers must be aware of the effects of using different visualization on students learning and how to use visualization. Burke, Greenbowe and Windschitl (1998) give advice that animation sequences should be short (20 - 60 seconds) and allow students to interact with appropriate feedback. The authors concluded that when care is taken in the design and use of animation appropriately, student understanding should improve as a result (Burke et al., 1998). In another study, Velazquez-Marcano and colleagues (2004) revealed that molecular-level animations combined with video clips of macroscopic phenomena were found more effective in enabling students to predict the outcome of effusion and diffusion problems than animation or video alone. They concluded that the combination of animation and video allowed students to interpret a concrete phenomenon in terms of an abstract concept.
Even though research has shown that animation can improve student understanding of abstract and dynamic process, the potential of animation to cause new and resistant misconceptions is also discussed (Tasker & Dalton, 2008). For example, the visualizations of the human body in the textbooks are presented in red and blue colors to represent arteries and veins. This might cause the misconception among young children that human blood has different colors. Rundgren and Tibell (2010) examined how secondary and tertiary students interpret the visualization of transport through the cell membrane in the form of a still image and an animation. These results also suggest that animations are more useful in helping students to understand the dynamic processes of the transport through the cell membrane. However, they found that the amount of information presented simultaneously in the animation gave rise to some difficulties for students.
- The use of multiple representations
Multi-representation has been suggested for use in science teaching to compensate for the limitation of using any single representation (Larkin & Simon, 1987). Ainsworth (2006) conducted a research on the advantage of multiple representations in science education. Based on her research, she proposed that the functions of multiple representations can be classified into three categories of (1) multiple representations can support learning by allowing for complementary information or complementary roles; (2) multiple representations can be used so that one representation constrains interpretations of another one; (3) constructing deeper understanding.
- Representation sequences
As a result of the benefit of using multiple representations in science teaching, it is important to consider the representation sequences and/or the combination of representations used in teaching (e.g. Ainsworth, 2006). Wu, Lin and Hsu (2013) conducted a study to compare the learning effect between two groups of different representation sequences (SD group: static –dynamic representations versus DS group: dynamic –static representations), and they revealed that the SD group of eight students gained significantly more factual knowledge. The representation sequences had no effect on students who had low spatial abilities. Wu and Puntambekar (2012) reviewed the effectiveness of different conditions, i.e. (1) one type of presentation versus another, (2) multiple representations versus a single one, and (3) teacher-provided versus student-generated representations as well as the findings of pairing multiple representations. Each teaching mode and pairing type has its own pros and cons, so it is advisable to make teachers try out in their own teaching practices and collect evidence to support teaching later.
Scaffolding is the idea that existing knowledge can be used as a supporting guide in understanding new information and it was introduced in educational psychology by Wood, Bruner and Ross (1976). Since visualization is highly related to students’ prior knowledge (e.g. Cook, 2006; Wu et al., 2013), scaffolding is one of the important teaching strategies to consider in science education, also when using visualization. Wu and Puntambekar (2012) suggest six types of scaffolding using multiple representations in science teaching: (1) dynamic linking (enabling translation between representations, i.e. showing concrete, diagrammatic, numerical in a single entity), (2) model progression (engaging students in constructing deviational links among different types of multiple representations, i.e. concreteness fading), (3) sequence (making students learn better by different representation sequences), (4) support in instructional materials (providing students with explicit instructional strategies, i.e. self-explanation), (5) teacher support (i.e. teachers’ verbal guide or questioning while students’ interact with visualizations) and (6) active engagement (making students active learners in exploiting the affordances of representations, i.e. letting students generate their own representations).
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