This book is part of a book series called Inventions That Changed the World .

This book has been graded for interest at 6-8 years.

There are 32 pages in this book. This book was published 2007 by Heinemann Educational Books .

Elizabeth Raum has written dozens of books for young readers, including biographies, history books, and picture books. She taught English and social studies to students in grades 7-12 and worked as a librarian in both elementary schools and colleges. She particularly enjoys visiting schools and libraries to talk with students about research and writing.