Nanotechnology deals with studying and manipulating matter at the atomic, molecular and macromolecular scale (1-100 nm). There are two main approaches to nanotechnology - top-down and bottom-up. Top-down involves reducing materials down to the nano scale while bottom-up constructs materials from atomic or molecular components. Nanotechnology has many uses in mechanical engineering like increasing lifespans of components and imparting unique properties to materials. Nanomaterials are substances with at least one dimension less than 100 nm, exhibiting novel optical, magnetic, electrical and other properties. Selected applications of nanomaterials and nanotechnology include energy, heavy industry, aerospace, catalysis, automobiles, coatings and steel.