Ball bearings are used in many different things as a way of preventing friction. They are used in between two objects as a way to move one item over the other without creating excess wear and tear. Ball bearings are exactly what they sound like. They are balls and because of their shape, they create less friction than something that is flat or has edges. Edges tend to dig in or scrape against other edges. The roundness of ball bearings allows them to roll with the objects.
The roundness of the bearings creates less contact between the bearing that is trying to move objects and the object being moved. A reduction in contact area means less friction. Grease also works with the bearings by keeping them lubricated. This allows them to move freely and keeps them from getting stuck or from causing friction from rubbing together.
Some ball bearings cause less friction than others. This is due to the type of material that the bearing is made out of. Steel, ceramic, rubber and plastic are all types of materials that can be used. Steel and ceramic are the most commonly used, although silicon has a lower surface resistance since they are created virtually smooth. The only issue with ball bearings is that they generally cannot handle an extreme amount of weight due to their small contact area.
