The ability of a material to recover its original shape partially or completely after the deforming force has been removed. The small amount of deformation that is not recovered is called permanent set or permanent elongation. Among common materials, glass and some metals are virtually 100% elastic, whereas vulcanized rubber and other elastomeric substances are in the range of 90% elastic after extension to rupture. So-called perfect elasticity is a property of atoms that show no energy loss on collision.See Modulus of Elasticity; Stress; Strain; Plasticity.