This article examines the socio-cultural activities that have direct and indirect impacts on critical thinking practices in primary science classrooms and what kinds of teachers' activities help to foster the development of critical thinking practices in children. Meanwhile, the constructivist and the socio-cultural theoretical dimensions have been taken as the conceptual bases for this study. This study has highlighted the major conceptual and methodological issues in identifying and assessing children's critical thinking as well as the educational implications for the promotion of children's original thinking. It used the qualitative research approach to pursue the objectives of the study. Science classroom observation and an interview with the science teachers were the major tools to collect the required information. Critical thinking is essential in critical science processes and practices. Hands-on, minds-on and hearts-on teaching learning strategies help to develop critical thinking to primary level children in science.