The Screw
The screw is really a twisted inclined plane. It allows movement from a lower position to a higher position but at the same time it moves it in a circle. That makes it take up less horizontal space. A screw can also act to hold things together in some cases.
Some examples of the uses of a screw are in a jar lid, a drill, a bolt, a light bulb, faucets, bottle caps and ball point pens. Circular stairways are also a form of a screw.
Another use of the screw is in a device known as a screw pump. A huge screw shape is lowered into the water and by turning the screw the water is moved up the twisted shaft and lifted to where it is needed. Screw pumps are often used in agricultural settings such as farms and for irrigation.