Reports on a study designed to ascertain the proportion of children at different Piagetian stages of development in the general population, in selective schools, and in super-selective schools. Advocates the use of developmental data in curriculum development work. (GS)

Questions the approach used to the topic of energy in Nuffield Secondary Science. Indicates that 14-year-old children will not be able to generalize from the experiments to see a pattern energing, and the concept of energy involves understanding of other concepts that the children have not yet attained. (GS)