ABSTRACT
If one wants to teach science to children of all ages, it seems vital to know their current knowledge about basic facts and laws of nature. This chapter will focus on children from about four to ten years old. Amazing knowledge structures will be revealed, not only pertaining to specific domains of intuitive physics and mathematics but also to scientific concepts in general. In particular, children's concepts will be shown to be governed by a cognitive algebra, pointing to the capabilities of coordinating variables and function thinking, both being essential for grasping the quantitative side of scientific concepts.
