The American Heritage Children's Science Dictionary Introduces Students In Grades 4 To 6 (Ages 9 To 12) To The Language And Ideas Of Science. Clear Definitions, Full-Color Art, And An Array Of Feature Notes And Tables Cover The Full Range Of Scientific Subjects, From Earth Science, Computers, Weather, And Outer Space To Basic Biology, Chemistry, Physics, Medicine, And Mathematics. "Did You Know?" Notes Present Amazing Facts On Topics From Earthworms To Gravity To Tornadoes. This Updated Edition Includes The New Developments That Young Learners Need To Know, Such As Pluto's Removal From The Category Of Planet, The Addition Of New Vocabulary Such As Dwarf Planet, Numerous Revisions To Other Entries Regarding The Solar System, And More. The Book Includes More Than 2,600 Clear, Complete, And Easy-To-follow Definitions In All Areas Of Science. Over 350 Detailed, Full-Color Photographs And Illustrations Enhance The Entries And There Are In-Depth Graphic Treatments Of Selected Topics Such As Aquifer, Carbon Cycle, Cell, Greenhouse Effect, Nuclear Reactor, And Plate Tectonics. Biographies Of Noteworthy Scientists Show How They Changed The Way People Look At The World. In Collaboration With Expert Science Consultants, The Editors Of The American Heritage Dictionaries Have Produced A Reference Work That Sparks Kids' Natural Curiosity And Inspires A Long-Lasting Interest In Science.