  We describe a simple and intuitive implementation of the method of finite
difference time domain simulations for propagating electromagnetic waves using
the simplest possible tools available in Microsoft Excel. The method overcomes
the usual obstacles of familiarity with programming languages as it relies on
little more than the cut and paste features that are standard in Excel. Avenues
of exploration by students are proposed and sample graphs are included. The
pedagogical effectiveness of the implementation was tested during an
Independent Activities Period class, composed of 80% freshmen, at MIT, and
yielded positive results.
