Final answer:
Screws are primarily used for holding things together by creating a tight bond between objects when turned into materials. Different screws vary in size, shape, and metal type, tailored for specific purposes.
Step-by-step explanation:
Screws are most commonly used for holding things together. They work by being turned (usually clockwise) into materials, where the threads on the screw create a tight bond between separate objects, effectively keeping them joined.
Just as how a wrench provides a mechanical advantage to tighten or loosen a nut, a screwdriver applies a torque to a screw to secure it in place.
The design and material of a screw, whether it's a flat-head or Phillips-head, as well as the length and the type of metal, are selected based on the specific task, such as fastening components or hanging heavy objects.
Not all screws are made of the same metal; for example, some might be made of steel, while others could be made of brass, each offering different physical characteristics suitable for different applications.