Abstract
In this research, lower secondary school students' recognition of decomposition by decomposer was investigated by questionnaire and interview. Changes in the students' recognition due to acquiring knowledge of soil were investigated on the basis of previous research. The results were as follows. (1) The students conceived decomposition as merely a change of living things, and did not notice the existence of the decomposer. (2) Many students thought that corpse became the soil by decomposition. They did not think have an understanding of decomposition where organic substances was decomposed into inorganic matter. (3) The students did not understand the composition of the soil. (4) When the teacher explained the composition of the soil to the students, some students understood that the corpse was decomposed into inorganic substances.
