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The Development Learning Activities Using Three Levels of Chemical Representation for Enhance Upper Secondary Students’ Organic Chemistry Concepts

The purpose of this study is to develop chemistry learning activities using three levels of chemical representations for enhancing upper secondary students’ organic chemistry concepts. The three levels of chemical representations are an important framework in chemistry education. Many students held misconceptions in organic chemistry because of students’ incapability to connect among the three levels of chemical representations. Development chemistry learning activities using three levels of chemical representations started by analyzing the applications of such a framework in organic chemistry lessons. The teaching strategy would follow the Life-Observation-Notation or LON approach. Chemistry learning activities were developed and received a quality examination by three experts who have experience in teaching chemistry to assess the content validity that arranged the chemistry learning activities according to the content. There are many teaching strategies used in these learning activities, such as concept map, demonstration, analogy, and hands on activities were developed. The learning activities provide abilities to relating the phenomena at a macroscopic level to a microscopic and symbolic level. The learning activities are expected to develop students’ understanding of chemical phenomena and organic chemistry concepts.


Introduction
Chemistry is a difficult subject to learn as being abstract and unrelated to everyday life, which often make many students misconception. The examination result in Chemistry showed the learning ability of the students. It was found that the examination score of most students were rated as medium to poor, and improvement was needed. It is because students' incapability to connect the three levels of representations in chemistry in which the nature of chemical explanation relate to three forms of chemical representation. Johnstone [1] distinguished the three levels of chemical representation. There are three levels of chemical representation as follows: (1) macroscopic level describe properties and visible phenomena in everyday life. (2) Microscopic level explanations at the particulate such as atoms, molecules and ions, and (3) symbolic representation relate to the use of chemical symbols, formulas and equations. It helps students understanding of three levels of chemical representation, which provide students to be better understand and explain chemistry phenomena. Research shows that students lack of translating the characteristics of chemistry between the macroscopic, microscopic and symbolic levels. The students need to understanding of chemical concepts by translate concepts using the macroscopic, microscopic and symbolic level [2]. Therefore, the teaching of chemistry should promote the three levels of chemical representation that might help develop students understanding of chemical phenomena, given the opportunity to experiment and discuss the observations. Students obtain more meaningful learning about chemical representations and improve their conceptual understanding [3,4]. The teaching strategy should be used several learning activities integrate with the three levels of representation, which linked to learning outcomes and evaluations. The representational competence are very important to students' learning in chemistry. Because students can develop not only knowledge but also need to be able to translate and transit across levels [5,6]. And students construct their own knowledge by connecting new knowledge with existing knowledge through the three levels of chemical representation.
For this reason, it is necessary to design chemistry learning activities that address the learning style and emphasizes a role for the students to construct their own knowledge by using three levels of chemical representations in organic chemistry concepts. The organic chemistry plays an important role in the secondary school chemistry, it relies on chemical representations. However, this study focused on designing chemistry learning activities to promote students' conceptual understanding of organic chemistry. The chemistry learning activities provide guidelines for the teachers' to teaching organic chemistry by follow the LON approach and using three levels of chemical representations. Improve students' ability to translate observations from macroscopic to a microscopic and symbolic level. Students are encouraged to find out for themselves about how and why chemical phenomena occur.
The purpose of the study is to develop chemistry learning activities using three levels of chemical representations for enhancing upper secondary Students' Organic Chemistry concepts.

Teaching chemistry using the Three levels of chemical representations
Ever since Johnstone [1] addressed the three levels of chemistry (macroscopic, microscopic, and symbolic) many studies have investigated how could support the construction, development, and evaluation of students' three levels of chemical representations. The three levels of chemical representations play important roles in chemical conceptual understanding. The three level of chemical representations are ways to express phenomena, objects, events, abstract concepts, ideas, processes, mechanisms, and even systems. There are three levels of chemical representation as follows: (1) macroscopic level describe properties and visible phenomena in everyday life. (2) microscopic level explanations at the particulate such as atoms, molecular and ions, and (3) symbolic representation relate to the use of chemical symbols, formulas and equations. The learning process should be taught one after the other: macroscopic level first, structural models on microscopic level afterwards, and finally chemical symbols on the symbolic level [7]. The activities with three levels of chemical representation helps students to develop not only knowledge but also discussion structural models of matter. When relating phenomena at a macroscopic level to representations of models at different levels, the necessity exists to use more specialized language using symbols with letters and images. The learning can become meaningful when embedded in the students' experiences with real phenomena, sequencing from concrete to abstract, using photographs and visuals, and invoking the use of representational competencies. Which can helps students improve their conceptual understanding in chemistry [8,9,10 and 11].

The use of Three levels of chemical representations in Chemistry Education
The three level of chemical representation involves the combination of more than one mode of representation. The successful learning of chemistry involves the constructions of mental model associations among the macroscopic, microscopic and symbolic levels for explain the chemical phenomena. Students improve their chemical conceptual understanding through interpretation of [12] has teaching by using MCIS to creation a scientific models and improve students' model in evaporation and condensation of the substance. It is found that students can create scientific model, can draw a model of particles that cannot be seen and used the model to explain the chemistry phenomena. Moreover, Mitchell et at.
[13] using a paper clip to represent the polymer chain and compare the reaction that students observed from experiment. As a result, using a paper clip to compare after the experiment helps students understand the reaction at the microscopic level. The chemistry learning activities used a picture describe about the movement of the particle in introduction of lesson. From the post test score the result showed that students had increased conceptual understanding. Moreover, after the students see the animation of the molecular shape, students was able to drawing molecular shape and have a better conceptual understanding [14,15]. From the literature review above , it shows the importance of teaching chemistry with three levels of chemical representation. Resulting students being able to understand the content and improve the chemical conceptual understanding.

Teaching chemistry using the Three levels of chemical representations approach
From the relate document, Vesna Ferk Savec, Irena Sajovic and Katarina S. Wissiak Grm [16], suggest the approach to teaching chemistry base on three levels of chemical representations approach, which improve students' understanding of chemical in everyday life and meaning of representations at the microscopic and symbolic levels. A teaching approach entitled Life -Observations -Notations (LON) was developed. The LON approach was start learning about chemical reactions from discussions about selected everyday life situations (macroscopic level). Everyday life situations are the learning process, which students understood that chemical reaction go on in everyday life. After that student present chemical phenomena with the use of models and animations of chemical reactions (microscopic level) then use symbolic notations for chemical reactions (symbolic). The learning process involves many students' activities such as hands on experiments, construction of representations of chemical reactions with the use of models, that improved their experimental skills and gained experiences. To follow the LON approach, teachers also stated that students' ability to connect observations from macroscopic level with their notations at microscopic and symbolic level improved.

Method
In this research, the chemistry learning activities using three levels of chemical representations for enhance upper secondary Students' organic chemistry concepts were developed. This section describe the methods used in this study that consisted of the research procedures and how learning activities were adapted and developed. The details for chemistry learning activities designing process were summarized as follows: 1. Studying basic data about the three levels of chemical representations for preparation of chemistry learning activities. This step involved studying and considering relate documents for developing chemistry learning activities using three level of chemical representations for enhance upper secondary Students' organic chemistry concepts. Related documents included the teaching using the three levels of chemical representation, upper secondary organic chemistry concepts and learning outcome. 2. Developing chemistry learning activities using three levels of chemical representations. The researcher set goals, learning outline and learning outcome. The content based on the Basic Education Curriculum A.D.2008. The content was organic chemistry in the chemistry subject for upper secondary students. After that the researcher selected teaching strategy to use in the study. It was the LON approach which students can translate concepts using the macroscopic, microscopic and symbolic level, and transit across three levels of chemical representations. There are 9 learning units with 20 periods (60 minute/period). 3. Consulting with expert who has experience in chemistry teaching to examine and verify the chemistry learning activities using the three levels of chemical representations. In this step, the chemistry learning activities validity and reliability were consulted by experts. 4. Revising the chemistry learning activities using three levels of chemical representations.
This step was adjusted according to the expert suggestion.

Results and Discussion
The findings of the study is chemistry learning activities using three levels of chemical representations design. The researcher studied and analyzed relate document regarding the teaching using the three levels of chemical representation development, upper secondary Organic Chemistry concepts, Thai National Education Standard and learning outcome. The information was used to design chemistry learning activities. The goals of the chemistry learning activities are as the follows: 1. To facilitate students' interest in learning chemistry with knowledge and conceptual understanding about organic chemistry. 2. To improve students' ability to translate observation from the macroscopic, microscopic and symbolic level through the LON approach.
There were nine main topics in organic chemistry for developing the chemistry learning activities. The topic covered carbon-carbon bond, functional groups, hydrocarbon (alkane, alkene, alkyne and aromatic), organic compound with oxygen (alcohol, phenol and ether), organic compound with oxygen (aldehyde, ketone), organic compound with oxygen (carboxylic acid), organic compound with oxygen (ester), organic compound with Nitrogen (amine) and organic compound with oxygen and Nitrogen (amide). These topic were analyzed into the chemistry learning activities using LON approach that promote upper secondary students' organic chemistry concepts. A framework of topic, activities using three levels of chemical representations follow LON approach and periods in each lesson plan was shown in Table 1.

Notations (N)
The first activity, students compare the structure of both paracetamol and aspirin. Then identify the functional group, which show the specific properties in molecules. The second activity is "The functional group", students guess the name of the functional group from the given structure. Life (L) The first activity was discussion about the acids which found in nature, such as formic acid and acetic acid. The second activity student do hands on activity to testing a real and fake vinegar (acetic acid). using in chemistry classroom. Use to observe the everyday phenomena through media, animation, modelling, writing formulas, symbols, chemical equations, calculations and graphs, which design for students to be able to transfer knowledge from macroscopic, microscopic and symbolic levels. That can enhance students' creating the correct chemistry concepts.

Conclusion
According to the basic data, the chemistry learning activity were developed base on using three levels of chemical representations for upper secondary students. The chemistry learning activities were examined by three expert who has experience in chemistry teaching. The chemistry learning activities were composed of nine topic. The topic covered carbon-carbon bond, functional groups, hydrocarbon (alkane, alkene, alkyne and aromatic), organic compound with oxygen (alcohol, phenol and ether), organic compound with oxygen (aldehyde, ketone), organic compound with oxygen (carboxylic acid), organic compound with oxygen (ester), organic compound with Nitrogen (amine) and organic compound with oxygen and Nitrogen (amide). Each topic takes 2 or 3 hours for all activities.
The teaching strategy would follow the LON approach. The LON approach is composed of three steps; 1) Life; 2) Observations; and 3) Notations. The LON approach was to start learning about organic chemistry from discussions about selected everyday life situations (macroscopic level). Which students understood that organic chemistry go on in everyday life and after that student present organic chemistry phenomena with the models and animations (microscopic level) then use symbolic notations for chemical reactions (symbolic). The learning process prefer many students' activities such as hands on experiments, construction of representations of organic chemistry with the models. That improved their experimental skills and students' ability to connect observations from macroscopic level with their notations at microscopic and symbolic level. The development of chemistry learning activity base on the LON approach might be enhance students' creating the correct chemistry concept.