The present paper describes a four-year project involving the development of a new instrument, the "Attitudes to School Science and Science" instrument, and its use to collect baseline attitudinal data from 280 students aged 11, 14, and 16 years. A key feature of the instrument is that it collects both descriptive and explanatory data in a pencil-and-paper format. The data gathered are probed in detail for explanatory insights into features that have emerged from more recent research on attitudes to science, in particular the suggestions that students view science outside school more positively than their experiences in science lessons, and that the early years of secondary education (ages approximately 11-14 years) are the most crucial in shaping attitudes. The study shows that positive attitudes to school science decline significantly between the ages of 11 and 14 years, with little appreciable downward change beyond this and, in some cases, a slight upturn. Female students display less positive attitudes and less clear-cut views on a variety of aspects of science. A sense of science being important in general terms, although not having much appeal for individual students, also emerged clearly from the data. The paper suggests that attitudinal instruments have a role to play in research, but that these need to be complemented by studies of detailed features of schools that may influence attitudes, some of which may not be apparent from data collected from students. (Contains 5 tables, 3 figures, and 1 note.)