Rau, Dana Meachen. <br/><br/>
Simple machines / 
Dana Meachen Rau. 
 - New York:  Scholastic,  2012. 
 - 48 pages. 
<br/><br/> How did workers in ancient civilizations move the huge stones they used to build cities? They rolled the stones over logs much like a modern-day conveyor belt.<br/><br/>Inside, you'll find:<br/>-How humans have used simple machines throughout history;<br/>-A timeline, photos- and how simple machines can be combined to do different jobs;<br/>-Surprising TRUE facts that will shock and amaze you! 
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<br/><br/><label>ISBN: </label>9780531265864 
<br/><br/><label>Dewey Class. No.: </label>SC R19 2012