A screw is a wedge that has been twisted around an axle. When it is rotated on a surface, it wedges itself tightly inside it.

Because screws are inclines, they can be used to lift things. For example, the function of a jack, which is a device used to lift cars in order to change their tires, is based on a screw. 



A screw is a wedge that has been twisted around an axle.

A screw can also be used to split wood. A wedge-shaped screw is extremely useful for this purpose.

Because nails and screws are wedges, they are useful for splitting wood.


Because nails and screws are wedges, they are useful for splitting wood.