The study aimed to investigate pre-service early childhood teachers' (PSTs) collective pedagogical content knowledge (cPCK) and personal pedagogical content knowledge (pPCK) on the knowledge used in scientific process (SP) through the content representation (CoRe) design, interview, and knowledge used in scientific process (KSP) forms. The data were collected from 36 sophomore PSTs' with a case study design. At the beginning of the data collection process, the PSTs' prior knowledge used in SP was determined individually through a pre-interview and the KSP form. At the conclusion of the 13-week science-focused course, post-interviews, the KSP form, and the CoRe form were applied again. The CoRe forms were filled collectively based on their science activities, which were designed at the end of the science course. The PCK developed by Magnusson et al. was used for data analysis and to decide on the main themes of the data. The study's findings revealed that the PSTs initially had some misconceptions relating to knowledge of SP. While the participants were confused about the knowledge used in SP and made incorrect definitions prior to the science-focused course, nearly all of the PSTs' conception were changed on all of the concepts used in SP and reflected the most confused skills (especially observing and measuring) to their teaching plans after the course. Therefore, their pPCK and cPCK development were supported by both the science-focused course and collaborative CoRe design. The findings of the study have important implications for government policies and teacher training programs.