International Journal of Humanities and Social Science Vol. 2 No. 6 [Special Issue – March 2012] 209 The Effect of PCK on Solving Selected Chemistry Problems Dr. Safa A. Zaid-ElKilani Dr. Adnan S. Doulat Dr. Mansour A. Alwraikat Department of Curriculum & Instruction Faculty of Educational Sciences University of Jordan Jordan Abstract This study examines the immediate and long term effect of using PCK approach of instruction that integrate macroscopic, symbolic and molecular representation of chemical phenomena on solving selected chemistry problems. Three groups of teachers' students had been examined in problem solving chemistry tests. The study shows that there is a significant difference between the groups who get PCK methodology course and those who do not; the results of the study also show that there are a long term effects of using such approach of instruction, there is no significant difference between the answers of group who just completed PCK methodology course, and those who get it the year before. Key words: PKC, solving problems, long term effect, symbolic, molecular representation 1- Introduction Important Objectives of elementary science education are to develop students' abilities to reason logically and to become competent problem solvers, consequently school teachers should posses the abilities to solve problems to foster such ability in their students, Ginns, & Watters, (1995). Clements, Krajcik,& Borko considered theory and modeling as important training elements to effective teacher programs, and that science teachers pedagogical content knowledge can be enhanced through such programs. Loughran et al., 2001 defines PCK as the knowledge that a teacher uses to provide teaching situations that help learners make sense of particular science content. Radford, (1998) show that PCK has been successful in improving the science content knowledge of 90 teachers during the 3 years in their graduate study. Understanding the PCK approach needs an understanding for the pedagogy theory, the nature of content to be represented, and the way to be represented. 1-1 Conceptual Change pedagogy Stofflett, & Stoddart, ( 1994) states that conceptual change pedagogy proved to be important to get red from previous misunderstanding for learning experience. Students in a science methods course received content instruction about conceptual change pedagogy. After instruction students in the conceptual change group gave qualitatively stronger response. Yager (1991), stated that teacher education must involve conceptual change on the part of teachers, thus making the role of the teacher, as a facilitator of problem solving in science more crucial. Gabel, Sherwood, & Enochs (1984) examine the problem –solving skills of high school students and concluded that one way of helping students overcome the algorithmic mode is to make certain that students understand the chemical concepts qualitatively before they are represented quantitatively. The discussion above leads to the second dimension of the problem that is the type of content that is crucial to problem solving in chemistry, in which its misunderstanding would hinder such ability. 1-2 Crucial Chemistry Content: Staver (1989) found that students harbor misconceptions about the mole that hinder problem solving, science textbooks fail to link the mole concept with the concept of standard number of particles, students believe that such concept is just associated with gram-molecule. Lawrenz (1986), assess the existing state of knowledge in science in-service training program, more than 50% of teachers responded correctly to question about atomic structure but fewer than 50% teachers responded correctly about mass relates to air , motion, and collision.