ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 59, Number 4
JKCSEZ 59(4)
August 20, 2015 

The purpose of this study was to identify the concepts of elementary school teachers related to three states of matter from activities of classifying various materials in life. The subjects were 25 teachers majored in primary science education at a graduate college of education and 10 teachers of elementary school located in a metropolitan city. A questionnaire and observation related to classification activities, and interviews were carried out and analyzed them qualitatively and quantitatively. From the analysis, we found that most elementary school teachers understood the classification criteria of three states of matter through macroscopic viewpoints and experienced difficulties in determining the state of mixture materials. After discussion of the classification results, the teachers’ concept was changed. But, when performing classification activity on the basis of the newly created concepts, it has not reached its results agreed. The result of this study shows that process of concept of science has been agreed in the same way to all people is not easy. Therefore, the teacher education programs to make possible to improve the ability capable of classifying the states of the various matters and to understand the nature of classification is required. In addition, deep discussion on the classification of the mixture is also necessary.