LeversBook - 1994
Levers are frequently found in nature. The body's ability to move, for example, is entirely dependent on a complex system of levers. Early humans discovered that levers tremendously magnify applied force. Children who haven't yet observed this process are fascinated by it. Numerous lever-based toys provide hours of additional exploration.
Publisher: Milwaukee : Gareth Stevens, 
Characteristics: 32 pages :,color illustrations ;,23 cm.
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