heglandscrew

 SCREWS 

Screw: an inclined plane wrapped around a cylinder. The screw is like an inclined plane.

Experiment: Get a board and two screws make sure that one screw has close threads and the other has far apart threads. Screw them into the board. Then decide which is easier to screw in.

Greatest Mechanical Advantage: The closer together the threads are the easier it is to use.

Everyday examples:spiral staircase, spiral slide, pencil sharpener, combine, snow blower, food grinder, parking ramp, cork screw, drill bit, drill, corn belt, bottle/jar lid, lawn mower

Websites about screws: http://en.wikipedia.org/wiki/screw http://www.needlepointers.com/ShowArticles.aspx?NavID=861

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