Now you see it, now you don't: The preschool child's conception of invisible particles in the context of dissolving.

Preschool children (aged 3–5 yrs) were asked to make judgments about the presence of material substances (e.g., sugar particles) and their properties (e.g., sweet taste) for solutions in which various powders were dissolved. Results indicate a substantial degree of recognition of the nature of matter in the context of dissolving. Ss distinguished visual appearance from underlying reality, recognized the conservation of taste, smell, and dangerous properties of substances, and by the age of 5, recognized that matter can be decomposed into tiny pieces, each too tiny to be seen by the naked eye. Overall performance improved in the 3–5 age range, with the major advance between the 3–4 yr olds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)