kinds of radiation carry different energies, and
the energy of a given kind of radiation
determines the kind of effect that it will have.
At the bottom end of the scale, radio
waves are so weak that they can only
cause increased movement in free
electrons. This is why metal antennas and
their mobile electrons are necessary to
transmit and receive such radiation.
Next come microwaves, which are
energetic enough to set polar molecules
like water moving faster. (Microwave
refers to the fact that their wavelength is
shorter than radio wavelengths.) Since
most foods are mostly water molecules,
microwave radiation is an effective
means of cooking.
Then there’s heat radiation, the cook’s
standard energy source, which causes the
increased movement of nonpolar
molecules — including carbohydrates,
proteins, and fats — as well as polar