Microwaves are a form of electromagnetic radiation with wavelengths in the
range from 
cm to m. This wavelength is long enough (frequency is low
enough) that an electronic device can be built which will produce the radiation
in quantity. At the lowest powers, a few milliwatts, such devices may be
either Gunn diodes or klystrons, and at higher powers, hundreds of watts or
more, a magnetron is used. The wavelength of microwaves is sufficiently short
that diffraction and interference are small enough to allow the radiated energy
to be focused or directed into a parallel (collimated) beam. Accordingly,
there are many practical uses for microwaves, including signal transmission,
heating hot chocolate, detecting thunderstorms, and measuring the speed of
baseballs. This experiment explores a few of their simplest optical
characteristics.