Both questions are surprisingly deep. Lets take
the easier one -- on the quartz crystal -- first.
Anytime you put an electric field across a
material, you create a force on the electrons and
protons in the material-- in opposing directions.
This can have many effects,depending on the
material, but for most materials there is a subtle
shift in the average positions of some electrons
relative to their"rest" positions. This motion
sets up an opposing electric field (called the
material polarization). Usually, this field simply
reduces the total apparent field in the material
-- the ratio of this new field to the external
charge is called the dielectric constant for the
material.In the case of Quartz and some other
materials, the electron drift causes the material
to adjust slightly the spacing of its crystal
lattice -- i.e. it changes shape, proportional to
the applied field.Usually this is a very small
shift -- but it is a reversible process --if you
squeeze the material -- you also get an apparent
electric field on the outside. The fancy name for
the phenomena is piezoelectric effect and it is
related to symmetry properties of the underlying
crystal or material.
Quartz is used in
frequency stabilization because it can be
fabricated into devices which 'ring' at a
Some materials are piezoelectric. That means
that bending or stretching or compressing the
material creates an electrical current. And the
vice versa is true--an electrical current causes
the material to bend, stretch, or compress. Quartz
crystals are a piezoelectric material.
what people do to make them vibrate is apply a
voltage, which distorts the crystal (kind of like
applying a force to compress a spring), and then
when the voltage is removed, the crystal springs
back into place, which creates an electric field.
The combination of these effects creates a kind of
circuit that vibrates with a specific frequency
(called the resonate frequency). The circuit is
called an RLC circuit, and I know how to use them,
and I the math to describe them, and I know that
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