Gears (Toybox Science)

by Chris Ollerenshaw (Author), PatTriggs (Author), PeterJ.Millard (Illustrator)

• Used

  Paperback
  1991

  $7.75

• Used

  Paperback
  1999

  $37.93

  What are gears used for? In this book children can find out by looking at toys and other objects and then use the blueprint at the end of the book to build their own helicopter.