This study analyzes the research trends of PCK (Pedagogical Content Knowledge) in Korean English classes from 2005 to 2019 across ten journal articles, two master’s theses, two doctoral dissertations, and five research reports. This was intended to provide hints for the future direction of English PCK studies. Six criteria—subject-matter knowledge, pedagogical knowledge, learner knowledge, curriculum knowledge, social context knowledge, and action research knowledge— have been applied to the analysis of the selected English PCK studies. The findings are as follows. Study on the subject-matter knowledge was the most frequent, appearing in 15 studies, mainly dealing with linguistic knowledge. In the field of pedagogical knowledge, studies on class design were most common, and in the field of learner knowledge, learner background and learner characteristics were equally studied. In the social context knowledge field, there were relatively few studies on parents, and in the field of action research knowledge, the number of studies corresponding to three sub-factors was the same. Our study concludes that to systematize the study of PCK for teacher professionalism in the subject matter of English, English PCK education should be done in both pre-service and in-service institutions and that PCK research environments should be provided to this end.

The purpose of this research is to investigate characteristics of science content knowledge and pedagogical content knowledge shown in the primary school science classes. Through analysis of classroom teaching, explore the features and differences between primary and secondary school science PCK. Using open-ended interviews with the teachers and group discussions on a regular basis to analyze and compare classes of five primary school teachers, the relationship between CK and PCK. Regardless of the school level the teacher's PCK and professionalism is required with varying focus and emphasis. The features of the primary school teacher's PCK are as follows: Firstly, elementary teach secondary teach content, teachers value pedagogical knowledge (PK) content knowledge (CK). The primary school PCK requires more of understanding of students and teaching methods that to subject areas. PCK be without content knowledge, and the teacher's PCK is subject-specific In addition to the characteristics of PCK in the primary school science teaching, ways to set up professional exchange or collaboration between primary and secondary teachers, and to provide supplementary in-service training focused on content knowledge for primary school teachers.

During the last three decades, earth science has been re-conceptualized as an interdisciplinary discipline entitled Earth System Science (ESS), which is based on knowledge of the physical earth system and human impact on the earth. While there is increasing effort to teach earth as a system in K-12 education, teachers' preparedness of to teach earth system is still in its infancy. This article focuses on reviewing the literature of teachers' knowledge of earth systems and of how teachers' knowledge of subject matter affects their teaching practice and pedagogical content knowledge (PCK). First, the study investigated a literature of PCK in general as well as in science teaching. Then this study duscuss what teachers' subject matter knowledge (SMK) is and what it means to be in teaching earth system science. Third, a literature of teachers' knowledge of earth system was reviewed. Finally, a number of suggestions and implications are made as to what teacher education program should do to better prepare future teachers to teach earth systems.