What Are Microwaves?
M icrowaves are very short waves of electromagnetic energy that travel at the speed of light (186,282 miles per second). Microwaves used in microwave ovens are in the same family of frequencies as the signals used in radio and television broadcasting.
The disturbance resulting from the pebble landing in
the water is transmitted through the water in the form
of ripples or waves. The water serves merely as a medium
through which the disturbance travels. In this sense,
these ripples are more like sound waves, which also
need a medium to travel through, normally using the
molecules that exist in the air or water. That is why,
for example, thundering rocket engines that would deafen
the ears under normal circumstances, would be inaudible
in the quiet vacuum of space.
On the other hand, electromagnetic forms of energy,
such as microwaves, radar waves, radio and TV waves,
travel millions of miles through the emptiness of space
without the need of any material medium through which
to travel. This is because, simply put, electromagnetic
waves are, in themselves, stored energy in motion.
Non-ionizing radiation is very different. Because of
the lower frequencies and reduced energy, it does not
have the same damaging and cumulative properties as
ionizing radiation. Microwave radiation (at 2450 MHz)
is non-ionizing, and in sufficient intensity will simply
cause the molecules in matter to vibrate, thereby causing
friction, which produces the heat that cooks the food.
The theory of electromagnetic energy can be illustrated
by what happens when a pebble is tossed into a quiet
pond. The pebble striking the still surface causes
the water to move up and down in the form of ripples,
or waves, that radiate in ever-widening circles over
the surface of the pond. These waves, which move up
and down at right angles to the direction they are
traveling, are called transverse waves. Microwaves
are examples of transverse waves.
A Phenomenal Force
Electromagnetic radiation begins with a phenomenon
that occurs when electric current flows through a conductor,
such as a copper wire. The motion of the electrons
through the wire produces a field of energy that surrounds
the wire and floats just off its surface. This floating
zone or cloud of energy is actually made up of two
different fields of energy, one electric and one magnetic.
The electric and magnetic waves that combine to form
an electromagnetic wave travel at right angles to each
other and to the direction of motion. If the current
flowing through the wire is made to oscillate at a
very rapid rate, the floating electromagnetic field
will break free and be launched into space.
Then, at the speed of light, the energy will radiate
outward in a pulsating pattern, much like the waves
in the pond. It is theorized that these waves are made
up of tiny packets of radiant energy called photons.
Streams of photons, each carrying energy and momentum,
travel in waves like an undulating string of cars on
a speeding roller coaster.
Is Microwave Radiation the Same as Radioactive Radiation?
No. There is a very important difference. As illustrated
by the frequency spectrum on the right, microwaves
used in microwave ovens, similar to microwaves used
in radar equipment, and telephone, television and radio
communication, are in the
non-ionizing
range of electromagnetic radiation. Non-ionizing radiation
is very different from
Ionizing radiation
. Ionizing radiation is extraordinarily high in frequency
(millions of trillions of cycles per second). It is,
therefore, extremely powerful and penetrating. Even
at low levels, ionizing radiation can damage the cells
of living tissue. In fact, these dangerous rays, have
enough energy and intensity to actually change (ionize)
the molecular structure of matter. In sufficient doses,
ionizing radiation can even cause genetic mutations.
As shown on the frequency spectrum, the ionizing range
of frequencies includes X-rays, gamma rays, and cosmic
rays. Ionizing radiation is the sort of radiation we
associate with radioactive substances like uranium,
radium, and the fall-out from atomic and thermonuclear
explosions.