I try to limit my number of non-NXT-related posts, but I'm so impressed with this new book that I have to share a bit about it.
The book is called "Making Things Move" by Dustyn R0berts. Dustyn is an engineer who also manages to teach non-engineers about design using non-techie language. She has been teaching a class at NYU called "Mechanisms and Things That Move" and the book is based on that class.
While many of the concepts in the book do require some math skills and the language/style of the writing isn't geared towards the 8-12 age group, the concepts by themselves are explained fairly easily and in simple language that I believe most kids will be able to follow (or at least spark enough curiosity to hunt down a parent or teacher to ask for help). Starting out with a good discussion on the 6 basic types of machines - lever, pulley, wheel and axle, inclined plane/wedges, screws, and gears - it just gets even better from there.
* Fastening techniques
* Friction and Torque (I learned a LOT in this chapter)
* Types of motors and how to control them
* Bearings, couplers, etc...
* way much more...
10 chapters in all, with projects galore to test what you've learned... it's an outstanding book. (She even throws in a breadboard and Arduino summary/primer in the back of the book.)
With lots of photos and great hand sketches, this book would make a great gift to any budding engineer, tinkerer, robot fanatic, and/or DIYer. I read it in a few days and am amazed at the amount of information packed into this book.