There is increasing interest in early childhood science education and a corresponding increase in research in this area. Studies have shown that in some countries the teaching of science in the early years remains low. These studies show that science pedagogy in the early years needs attention, despite the myriad opportunities afforded for the informal teaching of science concepts. What is not known is how teachers interpret the opportunities for science moments in these play-based environments. In drawing upon cultural-historical theory, this paper examines how teachers use the preschool environment to promote the teaching of science concepts. Specifically, two preschool teachers from one preschool site participated in an indoor and outdoor science walk where their discussion of the affordances for science learning was digitally recorded. Hedegaard's (2008) three-step analysis procedure and Tu's (2006) sciencing categories were used to analyse the data. Findings show that teachers in the same preschool setting have different levels of science awareness for the possibilities of informally teaching science. Specifically, an activity-oriented sciencing approach and a conceptually oriented sciencing attitude emerged. The complexity of teacher engagement in science teaching in play-based settings and their conceptualisation of science affordances in the environment point to new understandings about the relations between teachers' belief and practices in science learning. Therefore, the findings of this study contribute to early year science education just at a time when the Australian Government is seeking greater outcomes for the learning of STEM in preschools (Australian Government 2009).