Talk summary: Materials at the nanoscale exhibit unique properties that reflect the non-scalable character of materials at this reduced length scale. These properties are often of emergent nature - that is, they are not commonly expected, or deduced, from knowledge learned at larger sizes. Through the development of computer-based classical and first-principles quantum computations and simulations we highlight and demonstrate such behavior in diverse nanoscale systems. The research program illustrated in this talk is pursued at the Georgia Tech Center for Computational Materials Science (CCMS), with the aim of uncovering through the use of nanoscale computational microscopy the physical origins that underlie and govern the size-evolution of materials properties when small is different.