The overall aim of the present study is to study model-based teaching and the collaborative inquiry learning of chemical processes and physical phenomena in preschool, with a specific focus on the verbal communication established between teachers and children (4-5 years old). According to variation theory, learning is always directed at a specific content, called the object of learning. This study aims at highlighting what 'threatens' the teacher's and preschool children's intersubjectivity during the teaching of chemistry and physics content, and at discussing possible ways to continue the teaching of an object of learning, once sufficient intersubjectivity in a teaching/learning situation has been lost. The result shows the need for the teacher to divide and split a larger object of learning, such as water purification, into smaller learning steps 'on the way' in order to hinder breaks in intersubjectivity that otherwise may arise. We introduce the notion of 'overarching object of learning' and 'intermediary object of learning', and the intermediary objects of learning identified in this study are categorized as belonging to three different themes: the role of words, the role of theoretical models and science concepts, and the role of analogies and abstractions. The teacher's awareness of intermediary objects of learning as critical aspects for children's individual learning is crucial for the teaching of everyday science in a preschool setting.