False-colour high-resolution electron micrographs (HREM) of slip in an atomic lattice of gold. In nature, the crystalline symmetry of atoms in a solid is upset by stress; distortions occur along planes of weakness, or slip planes, where whole blocks of atoms slide over each other. The resistance of an atomic lattice to slip determines a material's bulk strength. When blocks of atoms move along parallel slip planes, twinning occurs. These 3 micrographs were taken 0. 07 seconds apart; the arrow shows the advance of a twin - the band of vertical atomic lattices. Magnification: x2. 5 million at 35mm size. (More information available) Yellow tint. Ref: MICROCOSMOS, fig. 7.3, p. 127