WJEC are revising their specifications for GCSE Science and GCSE Additional Science for first teaching from September 2011. As well as covering important scientific concepts, they highlight the role of scientific investigation in developing understanding, testing ideas and drawing conclusions. They also show how the science of the classroom relates to the world around us. This book fully supports the aims of the GCSE Additional Science specification by providing clear explanations, definitions of key terms, questions to test understanding and clearly identified Science Skills exercises. It also shows - how to evaluate evidence and draw conclusions - the implications of science for society - the role of models in science - the importance of practical work