We investigate the properties and dynamics of defects in several disparate physical systems spanning a factor of 10^15 in length scale and develop theoretical and experimental tools to facilitate their study. In particular, we present results from dislocations in atomic systems all the way to the creation of non-equilibrium vortex states in human crowds. At the smallest scales, we develop a framework to use interatomic models to study material properties using molecular dynamics of atoms. We describe the complex microstructure that forms when atomic materials are plastically deformed using continuum dislocation dynamics. Using similar techniques we simulate focal conic defects using a continuum model for smectic-A liquid crystals. At slightly larger scales we develop an experimental technique to measure the nonlinear stresses around individual vacancies, dislocations, and grain boundaries in colloidal crystals. On human length scales we describe the formation of vortex-like states at heavy metal concerts and the spread of zombism across the continental United States. Finally, we develop a new method to extract particle sizes and positions from confocal images at a resolution 10 − 100× higher than current methods, reaching 1 nm in precision.