This series looks at how and why we measure, encouraging children to discover for themselves how standard measuring sytems have developed. Children can make their own measuring tools, based on authentic ancient and modern instruments. There are experiments to try and a list of important events shows the history of measuring. The book is suitable for National Curriculum Science, Maths and History at Key Stage 2. This book examines time, from ancient calendars to photo-finishes, including day and night, the seasons, time-zones, timetables and the 24-hour clock.