How does lubrication reduce friction?

Question

How does lubrication reduce friction?

Answer 1

By eliminating solid-solid sliding contact. A solid is defined as a material that can support shear (lateral force). When two solids come into contact, imperfections in the surface interfer with each other and resist slide by their shear strength. Liquids or micoscopic balls of graphite (dry lubricant) flow or roll to reduce shear forces the result in friction.

Answer 2

When things are wet, they slide better.  

Answer 3

The molecules of a lubricant such as oil or grease slide past each other more easily than say two pieces of metal. That is why they are liquid and not solid because the molecules can move.