We report here on the first of two evaluations of a national project (Getting Practical: Improving Practical Work in Science—IPWiS) designed to improve the effectiveness of practical work in both primary and secondary schools in England. This first baseline evaluation of the effectiveness of practical work is based on a study of a diverse range of 30 practical lessons undertaken in non‐selective primary (n = 10) and secondary (n = 20) schools prior to the teachers undertaking a training intervention designed to improve their effective use of practical work. A multi‐site case study approach employing a condensed fieldwork strategy was used in which data were collected, using audiotape‐recorded discussions, interviews, and observational field notes. The analysis, based on work by Millar et al. and Tiberghien, considers what students do and think relative to what their teacher intended them to do and think. In both primary and secondary schools, the widespread use of highly structured “recipe” style tasks meant that practical work was highly effective in enabling students (n = 857) to do what the teacher intended. Whilst tasks in primary schools tended to be shorter than in secondary schools, with more time devoted to helping students understand the meaning of new scientific words, neither primary nor secondary teachers' lesson plans incorporated explicit strategies to assist students in making links between their observations and scientific ideas. As such, tasks were less effective in enabling students to use the intended scientific ideas to understand their actions and reflect upon the data they collected. These findings suggest that practical work might be made more effective, in terms of developing students' conceptual understanding—an aim of the IPWiS project—if teachers adopted a more “hands‐on” and “minds‐on” approach and explicitly planned how students were to link these two essential components of practical work. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 49: 1035–1055, 2012