English and Turkish pupils’ understanding of decomposition

Conclusion

This study presented the students' levels of understanding about decomposition after a traditional ecology teaching in England and in Turkey. Students have constructed their own ideas about decomposition and four questions explored students' ideas on that concept both in everyday and in school science context. Students were asked for four questions to probe understanding of decay or decomposition in different contexts. Students were expected to response the questions explaining micro-organisms broke down organic or dead plant/animals, and organic materials were recycled in the ecosystems and recycling was used more often in everyday life.

Despite the fact that the English students' responses showed greater sound understanding than the Turkish students' responses did, the English and Turkish students' responses tended to show similar partial understanding in explaining decomposition. In general, students gave more reasonable answers relating to decay for the Question 3-4 while they could not explain the same concepts properly in Question 1-2. The difficulty the students appeared to have was not in ‘knowing' but in being able to ‘use' their knowledge although such ‘unfamiliar' instances required almost the same explanations. Students were more familiar with the decay of fruits, such as apples; pears or oranges at home or in nature, and also the decomposition through rusting of tin cans in nature. On the other hand, small minority students showed their knowledge that dead plants/animals or micro-organisms like bacteria broke down organic materials.

Students had also some common misconceptions, such as some students considered producers, consumers, and soil was responsible for decay in an ecosystem; tin cans were decayed by bacteria in longer time than the orange peels; the apples loose their original shape, decayed, and had a bad smell because of oxygen, sun, vitamins, and minerals. Adeniyi (1985) stressed that although some of misconceptions might have existed before instruction, a few of them appeared after instruction. Students' prior misconceptions tented to block understanding of new concepts. Students' misconceptions seemed to reflect an adequacy of the curriculum or instruction or both. To obtain meaningful learning, determining students' level of understanding of science concepts, such as decomposition, especially the students' misunderstandings could be very useful for improving teaching. “If we as teachers want to help pupils to obtain more extensive knowledge of the environment, we ourselves must know more about children's ideas about different phenomena, in order to learn about the pupils' own starting-points for learning. Then, we would be able to create teaching situations in which the children' ideas will be challenged” (Hellden, 1992b, p.1).

In conclusion, the English students appeared to perform better than the Turkish students in providing more ideas with higher levels of understanding of decomposition and the difference was significant according to the result of chi-square test. The students' levels of understandings should be considered by teachers and curriculum developers to remediate students' misunderstandings of decomposition and increasing understanding of science topics at different levels. Therefore, it was hope that the results of the study to be helpful for designing science instruction in aiming to facilitate conceptual change about decomposition.

In recent literature, there were several researches about students' misconceptions on science concepts and their remediation by several conceptual change methodologies (Posner, Strike, Hewson, & Gertzog, 1982), such as conceptual change texts, concept maps, and analogy etc. have been used for the remediate students' conceptions. Stavy (1991) recommended using analogies to overcome misconceptions about conservation of matter. Özkan (2001) stressed that the conceptual change text oriented instruction increased seventh grade level students' ecology achievement. Çetin (2003) also reported that the conceptual change text oriented instruction accompanied by demonstrations in small groups was more effective to eliminate students' misconceptions in ecology, and increase understanding of ecology at ninth grade level than the traditional instruction.

Moreover, there have been observed few cross-cultural studies in science education (Bogdanov & Viiri, 1999; Aldridge & Fraser, 2000; Saglam & Robin, 2006) though there were many studies explored students' conceptions on science concepts in different countries. There was a need for further cross-cultural studies about ecology, especially on decomposition to see whether they would have similar findings or not.