Occasionally we have customers come to us with shattered windows, saying the glass either exploded while they were driving or that they came out to a shattered window.
Their initial thoughts are usually that someone shot the glass (yes, with a gun) or that some pesky neighbor kid must have broken the glass with a rock
While these scenarios are not impossible, in most cases of glass exploding, no one is at fault. The truth of the matter is your glass did spontaneously explode. Why, you ask? Well, the explanation is rather simple.
Why does it “explode”?
All glass in your vehicle is made of safety glass also known as tempered glass. This means when it breaks, it shatters to avoid having large shards of glass cutting passengers. This also means that the glass is also under a certain level of pressure at the molecular level. However, it is still MUCH stronger than regular glass.
“Enough science, what happened!?”
Okay, okay. Here’s what happens. Your car windows or back glass at some point are nicked with a rock. This most likely happens while driving and yes, rocks can kick up and hit the back of your vehicle.
That small nick or chip creates a weakness in the structure of the glass, making it much more susceptible to temperature changes, and other stresses.
So later that week, month, or year, when the temperature inside and outside your vehicle is drastically different or significant stress is placed on the glass, it shatters.
Why doesn’t it just spread and crack like a windshield?
Again, the windshield and the rest of the glass in your vehicle are made slightly differently. The windshield is made of two pieces of glass laminated together. The rest of the glass in your car is one pane of safety glass. The purpose of safety glass is to shatter so that cracks DON’T form, leading to large glass shards.
Sorry to break (no pun intended) the excitement of the exploding glass mystery. Your glass simply exploded because something hit it before, and the stress of the impact caught up with it later when further stress was added.
Be safe out there!
Author: B. Delamater