Man first produced glass by accident about the year 5000 B.C.
Phoenician sailors feasting on a beach near Belus in Asia
Minor, could find no stones on which to place their cooking
pots, therefore they set them on blocks of soda carried by
their ship as cargo. As the fire’s heat increased, the sand
and soda turned to molten glass.
The first useful glass objects date to Egypt’s 18th dynasty,
about 1500 B.C. Egyptians attached metal rods to silica paste
cores, which they dipped repeatedly into molten glass to
produce small bottles.
Glassblowing, a Babylonian
discovery, probably came about when glassmakers using the
‘core-dipped method switched to hollow metal rods to hold
silica paste cores and then discovered that molten glass could
be blown into shapes.
Glassmaking was revived in
Venice as a result of that Italian state’s trade contacts with
Byzantium. About 1675, the English learned to add lead oxide
to the basic glass formula, and the resulting solid, heavy and
durable vessels progressively replaced the fragile glasses of
Venice. During the 1800s, glass technology improved rapidly. A
hand-operated split mold developed in 1821 ended the age of
blowing individual bottles, glasses and flasks. A
semi-automatic bottle machine perfected 50 years later
mass-produced bottles and turned them into the everyday
miracle they are today.
The Nature of Glass
Physical structure does not
conform to liquid, solid or gas. Glass actually is more of a
liquid than the solid it appears to be. It is an inorganic
product of fusion which has cooled to a rigid condition
without crystallizing. Glass can be transparent, translucent
or opaque. It is non-porous, non- absorptive and impervious to
the common elements and many harsh chemicals and liquids. It
is exceptionally resistant to abrasion and surface scratches.
It is one of the best electrical insulation materials, yet can
be treated to conduct electricity. Glass has lower head
conductivity than most metals and can possess a very low, zero
or even negative coefficient of expansion. Because it contains
a large proportion of silica and is produced by the action of
heat upon that silica, it is generally categorized as a
ceramic. It is a thermoplastic material, which softens when
heated and hardens when cooled.
