This is the third book of a three-year science course for pupils covering the syllabus for Key Stage 3. It includes topics which encourage communication and an awareness of the applications and economic, social and technological implications of science. The book offers three elements to cater for a full range of abilities, consisting of the core which is suitable for all, reinforcement which includes exercises aimed at reinforcing the core material and extensions which are designed to develop material for the more able. Each unit in the book stresses key skills throughout, ranging from general writing and practical skills to those involving experimental design and hypothesizing and contains regular checkpoints for pupil assessment and to facilitate teacher control of pupil routes through particular tasks.