A procedure is suggested with the view to increase efficiency of acquisition by schoolchildren of the natural science data. The procedure is based on the theory of learning activity developed in S.L. Rubinstein's and A.N. Leontiev's schools. Some learning devices are considered which seek to put the pupil into the position of a subject of an object-transformation activity. This goal is achieved through creation of problem situations at a lesson; dealing with them pupils simultaneously master the meaningful and operational aspects of information.