HOW THE SCREW WORKS:
The screw's threads move an object up or down as the screw turns. Like a jar of peanut butter. Depending on the direction you twist the lid, the lid moves up and down. The screw is a simple machine because it allow wrk to be done over a long distance. It also makes work a lot easier.
EXAMPLES OF SCREWS:
-brace and bits
-screw lid jar
-swivel piano stool
WHAT THEY ARE SUPPOSED TO DO:
They are designed to change the direction of effort. When you are making a motion machine the screw can be used in three ways, to fasten objects together, to push or pull objects, or to raise or lower heavy objects. With the screw, circular motion is turned into forward motion. This is how a fan creates cold air to keep you cool on a warm summer day.
-do work over a longer distance
-make work a lot easier
-help us open jars (peanut butter!)
-sometimes they require a lot of effort
-they take longer to use
Dictionary Definition- a metal fastener having a tapered shank with a helical thread, and topped with a slotted head, driven into wood or the like by rotating, esp. by means of a screwdriver.