Science is now recognized as an essential subject for the 1990s with particular emphasis placed on science as a subject area within the National Curriculum. This book, therefore, provides a reference source for information on scientific facts. It features an A-Z index with each entry categorized with a symbol across nine subject areas: astronomy, biography, chemistry, earth sciences, electronics, life sciences, mathematics, physics and technology. Also included is a three-level system of cross-referencing, an index to encourage in-depth study and over 60 extended entries to provide a source of information for school projects. Numerous experiments, fact boxes, biographies and factual nuggets offer additional details.