Science teaching is essentially a practical activity, with a long tradition of pupil experimental work in schools. And yet, there are still questions about its most appropriate role and the reality of what is actually achieved. What is the purpose of doing practical work? - to increase theoretical understanding or to develop practical competencies? What does it mean to be good at doing sciences? What is the relationship between theoretical understanding and practical performance? How important are such factors as motivation and commitment? How can we assess a student's practical ability in a way which is valid and reliable and at the same time encourages, rather than destroys, good scientific practice in schools? This book addresses such questions. By bringing together the latest insights and research findings new perspectives and guidelines are developed. This book provides a re-affirmation of the importance of practical activity in science, centred on problem-solving investigations. It advocates the need for students to engage in whole practical tasks, in which all aspects of knowlege, (tacit as well as explicit), of practical ability, and of personal attributes of commitment and creativity, are iteratively interacting in holistic activity. While considering the particularly pertinent issues arising from the National Curriculum for Science in England, its discussion is equally germane to all concerned with developing good practical work in schools. If practical work is to merit the time, money and effort demanded by it in school science teaching, it must find a valid and convincing case for its existence. This book provides such a well argued justification.