The American Heritage® Student Science Dictionary, Second Edition, for students in grades 7 and up (ages 12 and up), provides comprehensive coverage of all the sciences. The dictionary includes more than 4, 500 entry words in A?Z format, 450 full-color photographs and drawings, and over 150 in-depth notes. Definitions are written in easy-to-understand language. Additional features include full-page treatment of complex topics such as photosynthesis, and several tables and charts, including the periodic table and a chart of geologic time. More than 250 new entries and senses have been added to this brand-new edition, including cloud computing, genetically modified organism, and the recently named elements flerovium and livermorium.