Marshall Brain's: How Much Does the Earth Weigh?

A very unique book - My lawnmower doesn't have a battery like a car does, so where does the electricity come from to ignite the spark plug? Why shouldn't I go swimming right after I eat? How do motion sensors work? Is it true that a diesel engine can operate under water while a gasoline engine cannot? How does caller ID work? What makes knuckles pop?

If you've ever scratched your head and thought, "why?," you'll love How Much Does the Earth Weigh? This fun book answers questions you never even thought to ask. There are over 100 questions to blow your mind! Written in Marshall Brain's award-winning style, this book explains in language you can understand the complexities behind some of the world's imponderables. You'll never look at a light socket, gas pump, or Web page the same way again! Fun to read with your kids and good for hours of discussions and investigations. Paperback, 144 pages.