The notion of an epistemological obstacle was introduced in 1938 by Gaston Bachelard in his article La formation de l'esprit scientifique [1]. Bachelard viewed epistemological obstacles as a very useful tool for studying the history of science, and in particular its pre-scientific era.
Epostemology, however, and - above all - Piaget's [2] genetic psychology justified the application of the notion of epistemological obstacles to the studies od processes that accompany the studying physics.
In the aricticle author will concentrate on obstacles resulting from the conflict between the ways of viewing the world by not mature children and the structures of ready-to-apply physics. We shall follow the manifestation of abstacles of general nature, likeeg the barrier of first impressions, as well as that of more specific barriers related to particular phenomena. The results of Piaget's work will help us to understand the raison d'être of individual obstacles.
We would like to stress that notion of an obstacle is relative and that an obstacle may manifest itself to a younger student while unnoticed by an adult. The choosing didactic measures consists not so much in avoiding obstacles as in conquering them [3].