The fourth edition of this comprehensive GCSE Physics text has been revised to cover the latest GCSE specifications. Additional material includes: the uses and dangers of radioactivity, nuclear stability and fundamental particles; a new section of scientific ideas and evidence; sections on communication and monitoring satellites; and the technological applications of physics, such as ultrasonic techniques, radio telescopes and car safety. Numerous questions from recent examination papers, at Foundation and Higher, level have been included at the ends of chapters, in the 10 sections of "Additional Questions" and in the large section of "Revision Questions".