Even though the internship has been promoted as a method for professional development in teacher education, Thai pre-service science teachers PCK during their internship is limited. Faichamta (2011) noted that several pre-service Science teachers in B. Ed. programmes had difficulties in implementing student-centred approach. They were also concerned with designing and organizing activities when planning their les sons. It was quite difficult for them to decide how to write the expected learning Out Comes and how to begin and sequence learning activities. Some pre-service teachers reflected that the learning outcomes they intended to reach were too general and did not show what Science concepts or skills the students were expected to acquire. An other concern was limited conceptual understanding of science. Some pre-service Science teachers discussed the fact that science concepts were too complex and difficult for them. They felt that they held misconceptions about many concepts. This concern inhibited them from choosing key concepts and designing learning activities.