This paper tries to show the evolution of students’ notions about the earth’s space, shape and gravitational force, obtained from a psichogenetic study previously carried out concerning the ideas which evolve to the notion of field of force (NARDI, 1990). The clinical interviews conducted with 45 secondary and high school students from São Paulo, Brazil, allow also a comparison between the data obtained and those reported by NUSSBAUM and NOVICK (1979), in order to suggest some aspects to be taken into consideration in the design of classroom activities about this subject.