The Glass We Know
It's a such common everyday material, I'm so sure that you'll be
able to see it everywhere you turn. Glass. Yup, that amorphous
liquid made out of sand.
If you've seen "Sweet Home Alabama" before, than you know what
I'm talking about. Glass is naturally made out of sand when it
is striked by lightning, morphing into brilliant shapes and
objects.
I don't think glass will ever cease to be useful, but even as it
is highly utilized in this world, glass can also be turned into
highly-valued works of art.
In fact, here's a tip for you: search the beaches to see if
you've found pieces of sea glass (not naturally occuring but the
kind that was thrown into the sea and molded by it after many
years into smooth, round shapes) because they have lately become
valuable and highly sought-after.
It was naturally occuring glass, like obsidian (glass naturally
created from volcaninc magma), that has been in use since the
stone age.
It was then used as a glaze for pottery until the method of
glass-blowing was developed in the first century b.c., making
glass more available. Its name is derived from the Latin word
for ice, "glacies."
Glass can be made out of pure silica, but to make the
glassmaking process easier, ash and lime is added. From these
basic ingredients, a variety of glass can be formed.
There is the float or annealed glass. Most of the world's flat
glass is annealed glass, since the process for making this was
invented in the 1950s by Sir Alastair Pilkington.
Molten glass is poured onto a tin bath and levels out to dry in
parallel, flat surfaces. Annealed glass is not suitable for
building as it breaks into shards.
Before annealed glass, there was plate glass, where it was
formed by rolling it flat.
There is such a kind of glass that is a bit tougher and safer
from breakage, called tempered glass. It is said to be six times
stronger than annealed glass, but it does have a few drawbacks.
If it does get broken, the whole glass panel will fall apart
into small bits. Also, since the portions of the tempered glass
are formed differently, the outer portion of the panel is more
susceptible to scratches.
Laminated glass was invented by Edouard Benedictus, after
discovering that a glass flask coated with cellulose nitrate was
dropped to the ground, shattered, but did not break.
This type of glass is more commonly used for windshields and
security purposes, as it is bulletproof. Laminated glass is
formed from typical annealed glass and a generous coating of
polyvinyl butyral.
Recently innovated is self-cleaning glass, which may just put
window-cleaners out of business. It is coated with titanium
dioxide. It enables ultraviolet rays to break down organic
compounds on the surface.
Water is also attracted to the surface of the glass, leaving a
thin coat that washes away these compounds.
Low-emmisivity glass has metallic-based coatings that hinder the
glass from transferring thermal energy, making it more
energy-efficient.
So whenever you're drinking a glass of water or marvelling at a
glass sculpture or modern glass architecture, think of what
you've just learned and how glass can change the world you live
in.