David Sang is the author of over 140 textbooks used in secondary schools around the world. He was a research physicist at Leeds University for nine years before turning to teaching. He has taught Physics in a high school, a sixth-form college and a university. Now he devotes himself to writing textbooks and developing other teaching resources including multimedia. He has edited books and websites aimed at helping teachers to teach Physics, and was formerly the physics editor of Catalyst magazine. Endorsed by the Science Museum. The Science Museum is dedicated to inspiring visitors with award-winning exhibitions, iconic objects and stories of incredible scientific achievement. The Science Museum’s world-class collection forms an enduring record of scientific, technological and medical advancement from across the globe. The Science Museum Group incorporates the Science Museum, the Science Museum Library and the Wellcome Collections of the History of Medicine in South Kensington; the Science and Industry Museum in Manchester; the National Railway Museum in York and Locomotion in Shildon; and the National Science and Media Museum in Bradford.