Asia-Pacific Forum on Science Learning and Teaching, Volume 8, Issue 2, Article 5 (Dec., 2007)
Gülcan ÇETİN
English and Turkish pupils’ understanding of decomposition

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Introduction

Students construct their own knowledge themselves, but their ideas may differ from the scientific views. These ideas can be valid, invalid, or incomplete, and may have a considerable influence on how and what students learn from their classroom experiences. There are many researches investigating students’ ideas related to several scientific concepts that they can be varied from scientific knowledge. This study area has recently attracted many researchers’ interest on children’s conceptions, misconceptions, understanding or conceptual change in science education (Gilbert & Watts, 1983; Driver, Squires, Rushworth, & Wood-Robinson, 1994). There were several researches investigating students’ conceptions about biology concepts, such as diffusion and osmosis (Odom & Barrow, 1995; Christianson & Fisher, 1999), genetics (Wood-Robinson, Lewis, & Leach, 2000), genetics and ecosystem (Bahar, Johnstone, & Hansell, 1999).

As students’ alternative ideas in science are resistant to change, it is very crucial to identify them before designing a science instruction or science curricula. Children’s conceptions may originate from daily life experiences, formal school context, and from each other. However, children’s ideas, language, tradition, cultural up-bringing of children, folklore, and myths are influencing factors on children’s conceptual understanding in science (Khatete, 1995). If science teachers and curriculum designers knew students’ alternative ideas related to science concepts, it might be helpful to prepare effective teaching schemes (Griffiths & Grant, 1985; O-Saki & Samiroden, 1990; BouJaoude, 1992).

Ecology is considered as one of the main topics in biology instruction and students have limited understanding and some difficulties about ecology. Many researches were carried out students’ understanding and conceptions concerning the key concepts of ecology, such as decomposition (Khatete, 1995); cycles of matter, flows of energy, and interdependency of organisms in ecosystems (Leach, 1995); greenhouse effect, CO2 emissions, ozone layer depletion (Andersson & Wallin, 2000), food chain, energy flow, pyramid of number/energy, and carbon cycle (Adeniyi, 1985; Çetin, 1998), biotic and abiotic factors, food chain and food web, and environmental pollution (Çetin, 2003), wastes, and recycling (Malandrakis, 2003). For example, Leach (1995) identified the ‘key ideas’ related to the nature of living organisms, and relationship between organisms based upon matter cycling, energy flow, and other factors, then these key ideas were used to identify ecological phenomena of 5 to 16 age ranged students attending urban and semi-rural schools in the North England (n=499). He found that while the young children characteristically thought of organisms only in the context of human activity and they could not make any relationship between organisms in ecosystems. The older ones had a tendency to clarify simple relationship between individual organisms involving food and shelter.

Andersson & Wallin (2000) demonstrated that Swedish students in grade 9 and grade 12 did not fully understand what fundamental societal changes would occur as a result of a drastic reduction in CO2 emission, but they knew well how injurious depletion of the ozone layer was to humans. Çetin (2003) also reported that 82 ninth grade students had some common misconceptions of the concepts of ecology; biotic and abiotic factors, food chain and food web, cycles of matters, and environmental pollution even after teaching ecology course. Secondary consumers provided food first to food chain. Produced foods were taken firstly by tertiary consumers that were animals. Phosphorus was substance that was found less in atmosphere layers. Animals in land started phosphorus cycle first, and then animals in sea started it again. After animals had taken phosphorus, they left it as compost to the nature. Then plants utilized it and animals ate plants again. Sometimes water seemed turbid because of bad weather conditions, not because of decay (Çetin, 2003).

Decomposition is carried out by micro-organisms; fungi and bacteria. Micro-organisms break down dead organic materials into inorganic materials. Thus, organic materials are made available for re-using in nature over and over again. Hellden (1992a) used an interview method with 2-6 grade students about decomposition in nature, conditions for growth and life, and plants in a meadow. A quantity of pupils at grade 4 and 6 thought that decomposition was a process in which no organisms took part. While some students mentioned that a piece of leaf or wood was not turned into soil completely, only part of it, some pupils pointed out that the rest of them just disappeared or a little was tuned into nourishment. Several students revealed that nail would be rusty, but most of them indicated that the rusty nail would remain and a few of them it would go down into ground. Some students indicated that a plastic lid and a glass jar would remain on the ground without decomposition. He concluded that the students had many alternative explanations regarding decomposition, although they studied actively these scientific phenomena during the instruction, and the teaching could not lead to conceptual change in the pupils’ conceptions.

Malandrakis (2003) has attempted to enlarge the children’s active participation to realize the degradability of organic materials and the non-degradability of others. He verified that the children realized the role of sun, water, and air to decay of materials, and they increased speed the decomposition process. The children figured out the environmental consequences from the dispose of these materials and recycling as the most appropriate solution for them. The students perceived wastes and recycling as two major environmental issues, and the students comprised them as an integral part of the environmental education curricula worldwide.

As mentioned above there have been few researches on decomposition and they concluded that the concepts of decomposition were not well understood by some students in general. Although there were some cross-cultural studies to measure how science concepts understood in different countries (Bogdanov & Viiri, 1999; Sağlam & Robin, 2006), there have not been observed any cross-cultural studies about ecology, specifically on decomposition according to the review of the literature. For example, Bogdanov & Viiri (1999) reported the preliminary results of the study of students’ understanding of the force concept. The students in the experimental Finnish group achieved a significantly higher level than the Russian group, although two groups showed to be almost equal. Sağlam & Robin (2006) explored the Turkish and English high school students’ understanding of electromagnetism. They figured out that many students showed misunderstandings and inconsistencies without a coherent framework of ideas about electromagnetism. Students common errors involved confusing of electric and magnetic field effects, seeing field lines as indicating a flow, using cause-effect reasoning in situations where it did not apply, and dealing with effects associated with the rate of change of a variable.

As a conclusion, the students belonged to each country had some common errors or difficulties of various science concepts and there was a need for further cross-cultural studies examining students’ alternative ideas about ecological concepts, specifically decomposition in different countries. As the students’ alternative ideas on decomposition could be independent of differences in curriculum or language of science instruction, they could be reached in other samples (Sağlam & Robin, 2006).

The main aim of this study was to explore seventh grade English and Turkish students’ levels of understandings of decomposition in two countries, in England and in Turkey, not to make a comparison the students’ achievements. It attempted to diagnose mainly how seventh grade English and Turkish students understood and explained decomposition of organic molecules, decomposition of biodegradable materials and non-biodegradable materials, decomposition in environment, producer, consumer and decomposer relationships in the cycle of materials, and environmental conservation in different everyday contexts after teaching ecology concepts. This study also indented to find out what the similarities of the English and the Turkish students’ understandings of the concepts of decomposition.

 

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