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Asia-Pacific Forum on Science Learning and Teaching, Volume 19, Issue 1, Article 10 (Jun., 2018) |
Chemistry is one of the important sciences to study in senior high school. In fact, the important of chemistry is not in line with students’ chemistry achievement. The students' chemistry learning achievement is low because students have difficulty in learning chemistry. Some of the subject matter of chemistry considered difficult by students include orbital and atomic hybridization (Nakiboglu, 2003), chemical bonds (Smith & Nakhleh, 2011), and chemical balance (Pedrosa & Dias, 2000; Sendur, Toprak, & Pekmez, 2010).
Johnstone (1993) says that learning in chemistry should reveal the phenomenon of chemical concepts and principles at the macroscopic, submicroscopic and symbolic levels. Macroscopic representation is a real observation of the chemical phenomena occurring by the five senses. Acquisition of this observation can be through daily experience, laboratory activities in the laboratory, and field studies. Things that can be observed include colour change, temperature, pH and the formation of precipitates during chemical reactions. The submicroscopic representation is a process that occurs at the level of atomic or molecular particles that explain macroscopic phenomena. The submicroscopic term refers to small and unobservable particle size but its existence is real, such as the movement of electrons, molecules, and atoms. Symbolic representation involves the use of symbols, reaction equations, chemical formulas, stoichiometric drawings, and diagrams. The three representations are interconnected and assist the students in understanding abstract chemical concepts. This is in accordance with Akaygun's (2016) assertion that the learning process in chemistry should involve an understanding of phenomena at the macroscopic, symbolic, and particulate levels. But the process of learning chemistry in high school in general only reveal phenomena at macroscopic, symbolic and mathematical levels whereas phenomena at the sub-microscopic level are still rarely applied. This is due to difficulties in explaining the structure, behavior, and processes that occur at the particulate level and its relation to the macroscopic level so that chemistry is being complecated.
According to Ainsworth (1999), the multi-representation-based learning have three objectives: a) to provide representations that contain complementary information or help complete the cognitive process; b) to limit the likelihood of misinterpretation in the use of other representations, and c) to encourage students to build a deep understanding of the situation. The application of learning based on multiple representations is inseparable from the role of the teacher as a learning facilitator. Teachers must also be able to apply effective learning, hit on the expected goals, and can help students work and think themselves so that learning chemistry will be more meaningful. One of the learning models that can be applied is the problem-solving learning model. Problem-solving is what a person does when the person does not know what to do (Gulacar, Bowman, & Feakes, 2013). Robertson (2001) says that problem-solving is something that involves a path to a goal. Meanwhile, Posamentier & Krulik (2009) said problem-solving is a way of thinking. That is, students can not exploit learning to overcome problems with no regard to techniques in the process. The problem-solving learning model will be possible for improving students’ learning motivation and providing challenges for authentic learning.
According to Polya (Polya, 1957), problem-solving is defined as the search for some appropriate action to achieve a goal that is clearly understood but not immediately achieved. Furthermore, he states that there are four steps to be taken to solve the problem: understanding problems, making plans, implementing plans and looking back. Based on the above explanation it can be said that the problem-solving learning model is one of the way for students to solve the problem by analytical thinking for achieving the desired goal. But in fact, many students solve chemical problems using only mathematical strategies but do not understand their chemical concepts well (Cracolice, Deming, & Ehlert, 2008). Therefore, problem-solving learning model based on multiple representations in chemistry can help students to understand the concepts of chemistry.
The purpose of this research was two-fold. The first was to identify the difficulty level of various types of chemical representation for students on chemical equilibrium. The second was to examine the effects of two different model of teaching and learning chemistry (problem-solving based on multiple representations and problem-solving) on the students’ cognitive achievement representtions in chemical equilibrium.
Research question of the study
The study aimed to answer the following research questions:
What kind/type of representations are most difficult/easily understood by students in chemical equilibrium?
Is there significant difference in students’ mean cognitive learning scores in chemical equilibrium among the two groups ?
