This tutorial review introduces the concepts necessary for understanding the generation of forces on charged objects in solution by externally applied electric fields. We focus on simple, idealized cases and conceptual understanding rather than quantitative modeling. We also discuss experiments in which electrophoretic forces on DNA were directly measured. This review is aimed at readers interested in the fundamentals of electrophoresis in general, as well as those with more specific interests in DNA electrophoresis, nanopores and optical tweezers.