According to Chalufour reading, it tells the importance of having Pedagogical Science Knowledge (PKS) including both understanding of science concepts, and of children and how they learn. Chalfour says the knowledge of children and how children learn are also important, as these are also the parts of pedagogical science knowledge. Accoring to Chalfour reading, teachers must have an understanding of how children learn in order to teach science so at the first; teachers should introduce the content at an adult level and then “translate this knowledge to appropriated content” for young children. Also, Chalufour says that “hand-on, inquiry-based investigation” is for both adults’ and children’s learning. It offers the opportunity to encourage teachers’ confidence in both learning and teaching science so in order to teach science effectively, teachers should have pedagogical science knowledge and confident in their own abilities to engage in science.