What are ball bearings for?

Wha??!?!?!??!?!?!?1

a small metal ball about half a centimeter high used to make things rotate for example:the pedals on your bike move around with the help of ball bearings

square balls are put between conncentric grooved discs. then any of the disc is rotated and square balls become sphere under application of some load.

Recycle it so it can be made into another ball bearing or something out of the medal. Recycle it so it can be made into another ball bearing or something out of the medal.

You can't, only tapered roller bearings as used in drums & rotors on some vehicles are adjustable. The rest are just sealed bearings and/or hub & bearing assemblies that are sealed