Bayer Corporation/Everyday Science
“SHATTERED” BY THE ROLLING STONES
Ever wonder how safety glass is made?
The answer can be found in EveryDay Science.
We all know that ordinary glass, when put in a stressful situation, has a tendency to…
That’s why, for things like automobile windshields, glassmakers have ways to make glass safer. Let’s clear it up once and for all by going back in time to when your windshield was first made.
HAZY TIME-TRAVEL SOUND, RESOLVING ON A WOBBLY SOUND OF GLASS STILL IN A LIQUIDSTATE
Once upon a time, your car windshield started out as an oozy liquid. All glass does. And the molecules of liquid glass are much further apart than when it’s a solid.
When it’s still in a liquid state, glass is very hot. But unlike regular glass, the outer surface of safety glass is suddenly quick-cooled to keep the molecules locked into a spread-out formation.
QUICK, ICY COOLING
Meanwhile, the inner core of safety glass is allowed to cool…down…slowly…to room temperature, causing it to shrink into a tighter molecular structure than its quick-cooled surface.
Hear what happens then?
SQUEAKING/STRESS PUSHING AND PULLING
A dynamic relationship is created between the shrunken inner core and the more spread-out outer surface of the glass. This constant pushing and pulling,
-or “tension stress”-makes your windshield about five times stronger than regular glass!
CAR ENGINE STARTING UP
But don’t hit the road quite yet.
CAR ENGINE STOPPING
There’s one more step. Windshield makers take two sheets of this “tension stressed” glass and place a clear plastic resin layer in between.
BLAST OF HEAT
This three-layer “safety sandwich” is then exposed to high temperatures to bond it all together. And there you have it.
‘TINK TINK” OF GLASS
Glass that’s strong enough to be used for sliding doors, shower stalls, and…
ENGINE STARTING UP AGAIN
…of course, car windshields.
“SHATTERED” UP AND UNDER
Well, thanks for letting us take a crack at explaining safety glass. And for being a part of EveryDay Science.
EveryDay Science is part of Bayer Corporation’s national education program Making Science Make Sense.