The research reported was associated with an early stage of developing a subunit of a curriculum within the framework of the Audio-Tutorial (A-T) Elementary Science Project at Cornell University. The research consisted of two parts: the development of an instructional unit for second-grade pupils and the formative evaluation associated with it. Both the design and analysis of concept learning were based on learning theory constructs of Ausubel. The experiment was conducted in a school considered as an average between an in-city school and a suburban school in terms of the socioeconomic level. The sample of second-grade pupils was stratified according to teachers' ratings and then randomly divided into two groups of 26 children each. One group received the individual A-T instructional unit followed by the interview test. One group was interviewed without any formal instruction. In analyses of responses on the interview tests five different notions of an Earth concept were identified and described. The notions appeared in similar frequencies in both of the groups of the study. The differences expressed in frequency of notion were small, suggesting that the instruction mode required revision and improvement. (Author/EB)