Nanotechnology sometimes involves mixing something very small into a larger, more conventional system. For example, mixing carbon nanotubes into a conventional polymer gives it added strength. Or, using a carbon nanotube as the channel between two larger, source-drain contacts creates a transistor with improved channel mobility. But simulating such systems becomes a huge challenge. The smaller parts of the system must be solved with great accuracy–for example, by simulating each atom within a carbon nanotube. But the same approach can't possibly be applied to the larger system–for example, to each atom in the thousands of polymer molecules in a realistic sample–or the whole problem would be too big to solve!

Multi-scale methods attempt to solve the problem by stitching together smaller domains (where atomistic models apply) and larger domains (where continuum models apply) into a coherent solution.

Learn more about multi-scale methods from the resources on this site, listed below.