Abstract
The present study had two purposes. One was to investigate children's and adults' informal knowledge of the earth's shape, especially on how they related the following two knowledges:“observational knowledge (e. g. the ground is flat)” and “knowledge from scientific information (e. g. the earth is round)”, both conflicting each other. A second purpose was to examine effects of instructions invented by the author on changes from inadequate into adequate knowledges. The results of Exp. I and II-A: showed that contrary to results of previous researches there were many children (Kindergarteners, 1st, 3rd-, 5th-grades) who couldnot relate two conflicting knowledges at all. Although getting older made more people able to relate them correctly if needed, for a long time they considered them as distinct. The results of Exp. II-B showed that in order for children to correctly relate these knowledges, it was necessary to instruct them explicitly on how to properly relate them, while clearly indicating the conflict between both knowledges.
