Abstract: This paper seeks to verify Piaget's experiments in the acquisition ofconservation in children. The preliminary, results show (a) thedevelopmental process of the logical thinking in the acquisition ofconservation of the children from four to nine; and (b) that thedevelopmental levels of conservation of substance, weight and volumeof 4-9 years old children are almost similar, whereas in Piaget'sexperiments they were different.

Key words: NULL