Piezoelectricity
The Greek word “piezo” means pressure.
In 1880, the brothers Jacques and Pierre
Curie (18 and 21 years old!) reported on
a discovery that the following year
W. G. Hankel called piezoelectricity, a
descriptive name for the phenomenon,
in which mechanical stress applied to
a sample of some materials apparently
creates electric charge on certain
surfaces of the sample.
1,2
?The total charge
of the sample remains unchanged by the
piezoelectric effect, but as a result of the
mechanical stress, surface charge density
is created.
3
?If a conductive material
covers the charged area, and a conductive
path exists from there to an electrometer,
a charge of equal in magnitude registers
in the electrometer, but that charge
belongs to the conductors, not
the sample.