"A lever is one of six simple machines that are designed to make different kinds of work easier. Lifting, pulling, pushing--all these tasks are more efficient when you use a simple machine. In Levers Lessen the Load: Simple Machines for Kids, readers learn how levers and fulcrums can help us move far more weight than we can on our own. Need to lift a heavy rock? Use a lever! Need to push a log out of the way? Use a lever! Know where else you can find...

"A teeter-totter is more than fun to play on, it's also a lever, one of the six simple machines. This accessible book introduces readers to the lever through real-world examples. They'll learn about simple and more complex inventions using the lever that have changed the world. Detailed pictures with thorough annotations explain important engineering concepts. Cool 'Technology in Action' spreads let readers get a close-up look at levers at work. This...