We report a longitudinal study carried out along 3 years in an early childhood education (ECE) classroom in which we examined children's (aged 3-6) engagement with science representations. The research questions are as follows: (1) How do children's science representations develop from ECE1 to ECE3? (2) What are the features and affordances of the teacher's scaffolding of the production of science representations and how is it facilitated from the first to the third year of ECE? The participants were 21 children and their teacher. The group was involved in long-term science projects that lasted for 5 months each. Sessions (N = 30) were recorded and children's drawings (N = 487) gathered. Data were analyzed using discourse and content analyses, coupled with an analysis of the intensity of scaffolding. The results indicate that children's representations of science phenomena became more complex along several dimensions. We have identified teacher's scaffolding strategies which supported children's increasing autonomy in producing representations. Implications are drawn for teaching science at the ECE level as well as for further research.